A. Zghiche

We study initial-state radiation events, ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\gamma}}_{\mathrm{ISR}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$, with data collected with the BABAR detector. We observe an accumulation of events near $4.26\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ in the invariant-mass spectrum of ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$. Fits to the mass spectrum indicate that a broad resonance with a mass of about $4.26\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to $90\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, depending on the fit hypothesis.

We have observed a narrow state near 2.32 GeV/c2 in the inclusive D+sπ0 invariant mass distribution from e+e− annihilation data at energies near 10.6 GeV. The observed width is consistent with the experimental resolution. The small intrinsic width and the quantum numbers of the final state indicate that the decay violates isospin conservation. The state has natural spin-parity and the low mass suggests a JP=0+ assignment. The data sample corresponds to an integrated luminosity of 91 fb−1 recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e+e− storage ring.Received 11 April 2003DOI:https://doi.org/10.1103/PhysRevLett.90.242001©2003 American Physical Society

We study the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ using $117\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected at the $Y(4S)$ resonance with the BABAR detector at the PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ asymmetric-energy storage ring. We measure the branching fractions $\mathcal{B}$ $({B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(116\ifmmode\pm\else\textpm\fi{}7(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}9(\mathrm{syst}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and $\mathcal{B}$ $({B}^{\ensuremath{-}}\ensuremath{\rightarrow}X(3872){\mathrm{K}}^{\ensuremath{-}})\ifmmode\times\else\texttimes\fi{}$ $\mathcal{B}$ $(X(3872)\ensuremath{\rightarrow}\mathrm{J}/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(1.28\ifmmode\pm\else\textpm\fi{}0.41)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and find the mass of the $X(3872)$ to be $3873.4\ifmmode\pm\else\textpm\fi{}1.4\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$. We search for the ${h}_{c}$ narrow state in the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}_{c}{K}^{\ensuremath{-}}$, ${h}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and for the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{D}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$, with ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. We set the $90%$ C.L. limits $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}_{c}{K}^{\ensuremath{-}})\ifmmode\times\else\texttimes\fi{}\mathcal{B}({h}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})<3.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{D}^{0}{\ensuremath{\pi}}^{\ensuremath{-}})<5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$.

We present results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 x 10(6) Upsilon(4S)-->B(-)B decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B(0) or B(-0) from its decay products. The amplitude of the CP asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta=0.741+/-0.067(stat)+/-0.034(syst) and |lambda|=0.948+/-0.051(stat)+/-0.030(syst). The magnitude of lambda is consistent with unity, in agreement with the standard model expectation of no direct CP violation in these modes.

We present a measurement of the cross section of the process e(+)e(-)-->pi(+)pi(-)psi(2S) from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the SLAC PEP-II e(+)e(-) storage rings. The study is based on 298 fb(-1) of data recorded with the BABAR detector. A structure is observed in the cross section not far above threshold, near 4.32 GeV. We also investigate the compatibility of this structure with the Y(4260) previously reported by this experiment.

The e+e- -> p anti-p cross section is determined over a range of p anti-p masses, from threshold to 4.5 GeV/c^2, by studying the e+e- -> p anti-p gamma process. The data set corresponds to an integrated luminosity of 232 fb^-1, collected with the BABAR detector at the PEP-II storage ring, at an e+e- center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, is measured for p anti-p masses below 3 GeV/c^2; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c^2. We also measure J/psi -> p anti-p and psi(2S) -> p anti-p branching fractions and set an upper limit on Y(4260) -> p anti-p production and decay.

We present evidence for D0-D(0) mixing in D(0)-->K(+)pi(-) decays from 384 fb(-1) of e(+)e(-) colliding-beam data recorded near square root s=10.6 GeV with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. We find the mixing parameters x('2)=[-0.22+/-0.30(stat)+/-0.21(syst)] x 10(-3) and y(')=[9.7+/-4.4(stat)+/-3.1(syst)] x 10(-3) and a correlation between them of -0.95. This result is inconsistent with the no-mixing hypothesis with a significance of 3.9 standard deviations. We measure R(D), the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates, to be [0.303+/-0.016(stat)+/-0.010(syst)]%. We find no evidence for CP violation.

The proton and deuteron structure functions F2p and F2d are measured in inelastic muon scattering with an average beam energy of 470 GeV. The data were taken at Fermilab experiment E665 during 1991 and 1992 using liquid hydrogen and deuterium targets. The F2 measurements are reported in the range 0.0008<x<0.6 and 0.2<Q2<75 GeV2. These are the first precise measurements of F2 in the low x and Q2 range of the data. In the high x range of the data where they overlap in x and Q2 with the measurements from NMC, the two measurements are in agreement. The E665 data also overlap in x with the DESY HERA data, and there is a smooth connection in Q2 between the two data sets. At high Q2 the E665 measurements are consistent with QCD-evolved leading twist structure function models. The data are qualitatively described by structure function models incorporating the hadronic nature of the photon at low Q2. The Q2 and the W dependence of the data measure the transition in the nature of the photon between a pointlike probe at high Q2 and a hadronic object at low Q2.Received 9 February 1996DOI:https://doi.org/10.1103/PhysRevD.54.3006©1996 American Physical Society

This paper reports measurements of processes: e+e−→γKS0K±π∓, e+e−→γK+K−π0, e+e−→γϕη, and e+e−→γϕπ0. The initial-state radiated photon allows to cover the hadronic final state in the energy range from thresholds up to ≈4.6 GeV. The overall size of the data sample analyzed is 232 fb−1, collected by the BABAR detector running at the PEP-II e+e− storage ring. From the Dalitz plot analysis of the KS0K±π∓ final state, moduli, and relative phase of the isoscalar and the isovector components of the e+e−→KK*(892) cross section are determined. Parameters of ϕ and ρ recurrences are also measured, using a global fitting procedure which exploits the interconnection among amplitudes, moduli, and phases of the e+e−→KS0K±π∓, K+K−π0, ϕη final states. The cross section for the OZI-forbidden process e+e−→ϕπ0, and the J/ψ branching fractions to KK*(892) and K+K−η are also measured.33 MoreReceived 28 October 2007DOI:https://doi.org/10.1103/PhysRevD.77.092002©2008 American Physical Society

The BaBar detector operated successfully at the PEP-II asymmetric e+e− collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking.

We present measurements of the flavor-changing neutral current decays B --> Kl+l- and B --> K*l+l-, where l+l- is either an e+e- or mu+mu- pair. The data sample comprises 229 x 10^6 Y(4s) -->to BBbar decays collected with the BaBar detector at the PEP-II e+e- storage ring. Flavor-changing neutral current decays are highly suppressed in the Standard Model and their predicted properties could be significantly modified by new physics at the electroweak scale. We measure the branching fractions B(B --> Kll) = (0.34 +- 0.07 +- 0.02) x 10^{-6}, B(B --> K*ll) = (0.78^{+0.19}_{-0.17} +- 0.11) x 10^{-6}, the direct CP asymmetries of these decays, and the relative abundances of decays to electrons and muons. For two regions in l+l- mass, above and below m(Jpsi), we measure partial branching fractions and the forward-backward angular asymmetry of the lepton pair. In these same regions we also measure the K* longitudinal polarization in B --> K*l+l- decays. Upper limits are obtained for the lepton flavor-violating decays B --> Kemu and B --> K*emu. All measurements are consistent with Standard Model expectations.

We measure the branching fraction for the flavor-changing neutral-current process B-->X(s)l(+)l(-) with a sample of 89x10(6) Upsilon(4S)-->BBmacr; events recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring. The final state is reconstructed from e(+)e(-) or micro(+)micro(-) pairs and a hadronic system X(s) consisting of one K+/- or K(0)(S) and up to two pions, with at most one pi(0). We observe a signal of 40+/-10(stat)+/-2(syst) events and extract the inclusive branching fraction B(B-->X(s)l(+)l(-))=(5.6+/-1.5(stat)+/-0.6(exp syst)+/-1.1(model syst))x10(-6) for ml(+)(l(-))>0.2 GeV/c(2).

We present a measurement of the direct CP violating asymmetry in the decay B0-->K+pi(-) using a data sample of 227x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We observe a total signal yield of nK-(pi(+))+nK+(pi(-))=1606+/-51 decays and measure the asymmetry (nK-(pi(+))-nK+(pi(-)))/(nK-(pi(+))+nK+(pi(-)))=-0.133+/-0.030(stat)+/-0.009(syst). The probability of observing such an asymmetry in the absence of direct CP violation is 1.3x10(-5), corresponding to 4.2 standard deviations.

We study e+e−→J/ψ cc¯ by measuring the invariant mass distribution recoiling against fully reconstructed J/ψ decays, using 124 fb−1 of data collected at a center-of-mass energy of 10.6 GeV with the BABAR detector. We observe signals for ηc(1S), χc0, and ηc(2S) in the recoil mass distribution, thus confirming previous measurements. We measure σ(e+e−→J/ψ+cc¯)B(cc¯→>2 charged) to be 17.6±2.8(stat)−2.1+1.5(syst) fb, 10.3±2.5(stat)−1.8+1.4(syst) fb, and 16.4±3.7(stat)−3.0+2.4(syst) fb with cc¯=ηc(1S), χc0, and ηc(2S), respectively.Received 25 June 2005DOI:https://doi.org/10.1103/PhysRevD.72.031101©2005 American Physical Society

We study the processes ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}2({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}){\ensuremath{\pi}}^{0}\ensuremath{\gamma}$, $2({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})\ensuremath{\eta}\ensuremath{\gamma}$, ${K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$ and ${K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\eta}\ensuremath{\gamma}$ with the hard photon radiated from the initial state. About 20 000, 4300, 5500, and 375 fully reconstructed events, respectively, are selected from $232\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of BABAR data. The invariant mass of the hadronic final state defines the effective ${e}^{+}{e}^{\ensuremath{-}}$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct ${e}^{+}{e}^{\ensuremath{-}}$ measurements, currently available only for the $\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and $\ensuremath{\omega}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ submodes of the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}2({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}){\ensuremath{\pi}}^{0}$ channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\omega}(782){\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and study the $\ensuremath{\omega}(1420)$ and $\ensuremath{\omega}(1650)$ resonances. In the charmonium region, we observe the $J/\ensuremath{\psi}$ in all these final states and several intermediate states, as well as the $\ensuremath{\psi}(2S)$ in some modes, and we measure the corresponding branching fractions.

We search for the production of doubly charmed baryons in e+e− annihilations at or near a center-of-mass energy of 10.58 GeV, in a data sample with an integrated luminosity of 232 fb−1 recorded with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. We search for Ξ+cc baryons in the final states Λ+cK−π+ and Ξ0cπ+, and Ξ++cc baryons in the final states Λ+cK−π+π+ and Ξ0cπ+π+. We find no evidence for the production of doubly charmed baryons.Received 18 May 2006DOI:https://doi.org/10.1103/PhysRevD.74.011103©2006 American Physical Society

We present a study of the decays B0,+→J/ψωK0,+ using 383×106 B¯¯¯B events obtained with the BABAR detector at PEP-II. We observe Y(3940)→J/ψω, with mass 3914.6+3.8−3.4(stat)±2.0(syst) MeV/c2, and width 34+12−8(stat)±5(syst) MeV. The ratio of B0 and B+ decay to YK is 0.27+0.28−0.23(stat)+0.04−0.01(syst), and the relevant B0 and B+ branching fractions are reported.Received 14 November 2007DOI:https://doi.org/10.1103/PhysRevLett.101.082001©2008 American Physical Society

We present a study of resonances in exclusive decays of $B$ mesons to ${\overline{D}}^{(*)}{D}^{(*)}K$. We report the observation of the decays $B\ensuremath{\rightarrow}{\overline{D}}^{(*)}{D}_{s1}^{+}(2536)$ where the ${D}_{s1}^{+}(2536)$ is reconstructed in the ${D}^{*0}{K}^{+}$ and ${D}^{*+}{K}_{S}^{0}$ decay channels. We report also the observation of the decays $B\ensuremath{\rightarrow}\ensuremath{\psi}(3770)K$ where the $\ensuremath{\psi}(3770)$ decays to ${\overline{D}}^{0}{D}^{0}$ and ${D}^{\ensuremath{-}}{D}^{+}$. In addition, we present the observation of an enhancement for the ${\overline{D}}^{*0}{D}^{0}$ invariant mass in the decays $B\ensuremath{\rightarrow}{\overline{D}}^{*0}{D}^{0}K$, at a mass of $({3875.1}_{\ensuremath{-}0.5}^{+0.7}\ifmmode\pm\else\textpm\fi{}0.5)\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ with a width of $({3.0}_{\ensuremath{-}1.4}^{+1.9}\ifmmode\pm\else\textpm\fi{}0.9)\text{ }\text{ }\mathrm{MeV}$ (the first errors are statistical and the second are systematic). Branching fractions and spin studies are shown for the three resonances. The results are based on $347\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected with the BABAR detector at the PEP-II $B$ factory.

The process e+e- --&gt; pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --&gt; e+e-)B(omega --&gt; 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --&gt; e+e-)B(phi --&gt; 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --&gt; pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --&gt; J/psi gamma --&gt; pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --&gt; pi+ pi- pi0)=(2.18 +/- 0.19)% has been measured.

We observe a new Ds meson with mass (2856.6±1.5stat±5.0syst) MeV/c2 and width (48±7stat±10syst) MeV/c2 decaying into D0K+ and D+K0S. In the same mass distributions, we also observe a broad structure with mass (2688±4stat±3syst) MeV/c2 and width (112±7stat±36syst) MeV/c2. To obtain this result, we use 240 fb−1 of data recorded by the BABAR detector at the PEP-II asymmetric-energy e+e− storage rings at the Stanford Linear Accelerator Center running at center-of-mass energies near 10.6 GeV.Received 27 July 2006DOI:https://doi.org/10.1103/PhysRevLett.97.222001©2006 American Physical Society

With a sample of approximately 89 x 10(6) B(-)B pairs collected with the BABAR detector, we perform a search for B meson decays into pairs of charmless vector mesons (phi, rho, and K*). We measure the branching fractions, determine the degree of longitudinal polarization, and search for CP violation asymmetries in the processes B+-->phiK(*+), B0-->phiK(*0), B+-->rho(0)K(*+), and B+-->rho(0)rho(+). We also set an upper limit on the branching fraction for the decay B0-->rho(0)rho(0).

We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with the photon radiated from the initial state. About 20,000, 33,000 and 4,000 fully reconstructed events, respectively, have been selected from 232 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that these data can be compared with the corresponding direct e+e- measurements. From the 3(pi+pi-), 2(pi+pi-pi0) and K+ K- 2(pi+pi-) mass spectra, the cross sections for the processes e+ e- --> 3(pi+pi-), e+ e- --> 2(pi+pi-pi0) and e+ e- --> K+ K- 2(pi+pi-) are measured for center-of-mass energies from production threshold to 4.5 GeV. The uncertainty in the cross section measurement is typically 6-15%. We observe the J/psi in all these final states and measure the corresponding branching fractions.

A search for the nonconservation of lepton flavor number in the decay τ±→μ±γ has been performed using 2.07×108 e+e−→τ+τ− events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of B(τ±→μ±γ)<6.8×10−8 at 90% confidence level.Received 16 February 2005DOI:https://doi.org/10.1103/PhysRevLett.95.041802©2005 American Physical Society

We study the initial-state-radiation processes e+e−→K+K−π+π−γ and e+e−→K+K−π0π0γ using an integrated luminosity of 232 fb−1 collected at the Υ(4S) mass with the BABAR detector at SLAC. Even though these reactions are dominated by intermediate states with excited kaons, we are able to study for the first time the cross section for e+e−→ϕ(1020)f0(980) as a function of center-of-mass energy. We observe a structure near threshold consistent with a 1−− resonance with mass m=2.175±0.010±0.015 GeV/c2 and width Γ=58±16±20 MeV. We observe no Y(4260) signal and set a limit of BY→ϕπ+π−⋅ΓYee<0.4 eV (90% confidence level), which excludes some models.Received 10 October 2006DOI:https://doi.org/10.1103/PhysRevD.74.091103©2006 American Physical Society

We present measurements of branching fractions and CP-violating asymmetries for two-body neutral B meson decays to charged pions and kaons based on a sample of about 88x10(6) Upsilon(4S)-->BB decays. From a time-independent fit we measure the charge-averaged branching fractions B(B0-->pi+pi-)=(4.7+/-0.6+/-0.2)x10(-6), B(B0-->K+pi-)=(17.9+/-0.9+/-0.7)x10(-6), and the direct CP-violating charge asymmetry A(Kpi)=-0.102+/-0.050+/-0.016 [-0.188,-0.016], where the ranges in square brackets indicate the 90% confidence intervals. From a time-dependent fit we measure the B0-->pi+pi- CP-violating parameters S(pipi)=0.02+/-0.34+/-0.05 [-0.54,+0.58] and C(pipi)=-0.30+/-0.25+/-0.04 [-0.72,+0.12].

In a study of B+→J/ψγK+ decays, we find evidence for the radiative decay X(3872)→J/ψγ with a statistical significance of 3.4σ. We measure the product of branching fractions B(B+→X(3872)K+)⋅B(X(3872)→J/ψγ)=(3.3±1.0±0.3)×10−6, where the uncertainties are statistical and systematic, respectively. We also measure the branching fraction B(B+→χc1K+)=(4.9±0.2±0.4)×10−4. These results are obtained from (287±3) million B¯¯¯B decays collected at the Υ(4S) resonance with the BABAR detector at the PEP-II B Factory at SLAC.Received 25 July 2006DOI:https://doi.org/10.1103/PhysRevD.74.071101©2006 American Physical Society

We study the e+e−→Λ¯¯¯Λγ, Λ¯¯¯Σ0γ, Σ0¯¯¯Σ0γ processes using 230 fb−1 of integrated luminosity collected by the BABAR detector at e+e− center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e+e−→Λ¯¯¯Λ, Λ¯¯¯Σ0, Σ0¯¯¯Σ0 are measured in the dibaryon mass range from threshold up to 3 GeV/c2. The ratio of electric and magnetic form factors, |GE/GM|, is measured for e+e−→Λ¯¯¯Λ, and limits on the relative phase between Λ form factors are obtained. We also measure the J/ψ→Λ¯¯¯Λ, Σ0¯¯¯Σ0, and ψ(2S)→Λ¯¯¯Λ branching fractions.24 MoreReceived 12 September 2007DOI:https://doi.org/10.1103/PhysRevD.76.092006©2007 American Physical Society

We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ and $K^+ K^- K^+ K^-$. We observe the $J/\psi$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/\psi (\to\mu^+\mu^-) \pi^+\pi^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/\psi\pi^+\pi^-$.

A search for charmed baryons decaying to $D^0 p$ reveals two states: the $Λ_c(2880)^+$ baryon and a previously unobserved state at a mass of [$2939.8\pm 1.3 \text{(stat.)}\pm 1.0 \text{(syst.)}$]~\mevcc and with an intrinsic width of [$17.5\pm 5.2 \text{(stat.)}\pm 5.9 \text{(syst.)}$]~\mev. Consistent and significant signals are observed for the $K^-π^+$ and $K^-π^+π^-π^+$ decay modes of the $D^0$ in 287 ${\rm fb}^{-1}$ annihilation data recorded by the BaBar detector at a center-of-mass energy of 10.58~${\rm GeV}/c^2$. There is no evidence in the $D^+ p$ spectrum of doubly-charged partners. The mass and intrinsic width of the $Λ_c(2880)^+$ baryon and relative yield of the two baryons are also measured.

A search for the nonconservation of lepton flavor in the decay τ±→e±γ has been performed with 2.07×108 e+e−→τ+τ− events collected by the BABAR detector at the SLAC PEP II storage ring at a center-of-mass energy near 10.58 GeV. We find no evidence for a signal and set an upper limit on the branching ratio of B(τ±→e±γ)<1.1×10−7 at 90% confidence level.Received 5 August 2005DOI:https://doi.org/10.1103/PhysRevLett.96.041801©2006 American Physical Society

Nuclear shadowing is observed in the per-nucleon cross sections of positive muons on carbon, calcium and lead as compared to deuterium. The data were taken by Fermilab experiment E665 using inelastically scattered muons of mean incident momentum 470 GeV/c. Cross-section ratios are presented in the kinematic region 0.0001<x Bj <0.56 and 0.1<Q 2<80 GeV2. The data are consistent with no significant ν orQ 2 dependence at fixedx Bj . Asx Bj decreases, the size of the shadowing effect, as well as itsA dependence, are found to approach the corresponding measurements in photoproduction.

We present updated measurements of time-dependent CP asymmetries in fully reconstructed neutral B decays containing a charmonium meson. The measurements reported here use a data sample of (465±5)×106 Υ(4S)→B¯¯¯B decays collected with the BABAR detector at the PEP-II asymmetric energy e+e− storage rings operating at the SLAC National Accelerator Laboratory. The time-dependent CP asymmetry parameters measured from JψK0S, JψK0L, ψ(2S)K0S, ηcK0S, χc1K0S, and J/ψK∗(892)0 decays are: Cf=0.024±0.020(stat)±0.016(syst) and −ηfSf=0.687±0.028(stat)±0.012(syst).Received 10 February 2009DOI:https://doi.org/10.1103/PhysRevD.79.072009©2009 American Physical Society

We study the processes $e^+ e^-\to K^+ K^- \pi^+\pi^-\gamma$, $K^+K^-\pi^0\pi^0\gamma$ and $K^+ K^- K^+ K^-\gamma$, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events, respectively, are selected from 232 \invfb of \babar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that the $K^+ K^- \pi^+\pi^-\gamma$ data can be compared with direct measurements of the $e^+ e^-\to K^+K^- \pipi$ reaction; no direct measurements exist for the $e^+ e^-\to K^+ K^- \pi^0\pi^0$ or $\epem\to K^+ K^- K^+ K^-$ reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\phi(1020) f_{0}(980)$ and study its structure near threshold. In the charmonium region, we observe the $J/\psi$ in all three final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) and obtain an upper limit of $\BR_{Y(4260)\to\phi\pi^+\pi^-}\cdot\Gamma^{Y}_{ee}<0.4 \ev$ at 90% C.L.

We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K±π∓π±. Using a sample of 226.0±2.5 million B¯¯¯B pairs collected by the BABAR detector, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for both charge-conjugate decays. We present measurements of the corresponding branching fractions and their charge asymmetries that supersede those of previous BABAR analyses. We find the charge asymmetries to be consistent with zero.Received 1 July 2005DOI:https://doi.org/10.1103/PhysRevD.72.072003©2005 American Physical Society

We report the first observation of an excited singly-charm baryon OmegaC* (css) in the radiative decay OmegaC0 Gamma, where the OmegaC0 baryon is reconstructed in the decays to the final states Omega-pi+, Omega-pi+pi0, Omega-pi+pi-pi+, and Cascade-K-pi+pi+. This analysis is performed using a dataset of 230.7 fb$-1} collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The mass difference between the OmegaC* and the OmegaC0 baryons is measured to be 70.8 +/- 1.0 (stat) +/- 1.1 (syst) MeV/c2. We also measure the ratio of inclusive production cross sections of OmegaC* and OmegaC0 in e+e- annihilation.

We present measurements of the semileptonic decays B--->D0tau-nutau, B--->D*0tau-nutau, B0-->D+tau-nutau, and B0-->D*+tau-nutau, which are potentially sensitive to non-standard model amplitudes. The data sample comprises 232x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector. From a combined fit to B- and B0 channels, we obtain the branching fractions B(B-->Dtau-nutau)=(0.86+/-0.24+/-0.11+/-0.06)% and B(B-->D*tau-nutau)=(1.62+/-0.31+/-0.10+/-0.05)% (normalized for the B0), where the uncertainties are statistical, systematic, and normalization-mode-related.

We use a sample of 384 million BBbar events collected with the Babar detector at the PEP-II e+e- collider to study angular distributions in the rare decays B -> K* l+l-, where l+l- is either e+e- or mu+mu-. For low dilepton invariant masses, m(l+l-)<2.5 GeV/c^2, we measure a lepton forward-backward asymmetry AFB=0.24 (+0.18,-0.23) +/- 0.05 and K* longitudinal polarization FL=0.35 +/- 0.16 +/- 0.04$. For m(l+l-)>3.2$ GeV/c^2, we measure AFB=0.76 (+0.52,-0.32) +/- 0.07 FL=0.71 (+0.20,-0.22) +/- 0.04.

We present results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 227 x 10(6) upsilon(4S) --> BB decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The amplitude of the CPasymmetry, sin2beta in the standard model, is derived from decay-time distributions from events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0 from its decay products. We measure sin2beta = 0.722 +/- 0.040(stat) +/- 0.023(syst) in agreement with the standard model expectation.

Longitudinal and transverse response functions, RL and RT, have been obtained in inclusive quasi-elastic electron scattering from 4 He and 208Pb, for momentum transfers between 300 and 650 MeV/c and energy transfers up to 350 MeV. A quenching of RL, ∼ 14% in 4He and ∼ 50% in 208Pb has been observed. Interpretations in terms of correlations and modification of nucleon form factors in the nuclear medium are discussed.

A narrow state, which we label DsJ(2458)+, with a mass 2458.0±1.0(stat)±1.0(syst)MeV/c2, is observed in the inclusive D+sπ0γ mass distribution in 91fb−1 of e+e− annihilation data recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e+e− storage ring. The observed width is consistent with the experimental resolution. The data favor decay through D*s(2112)+π0 rather than through D*sJ(2317)+γ. An analysis of D+sπ0 data accounting for the influence of the DsJ(2458)+ produces a D*sJ(2317)+ mass of 2317.3±0.4(stat)±0.8(syst)MeV/c2. Received 24 October 2003DOI:https://doi.org/10.1103/PhysRevD.69.031101©2004 American Physical Society

We present results of a search for the X(3872) in B0→X(3872)K0S,X(3872)→J/ψπ+π−, improved measurements of B−→X(3872)K−, and a study of the J/ψπ+π− mass region above the X(3872). We use 232×106 B¯¯¯B pairs collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e+e− asymmetric-energy storage rings. The results include the 90% confidence interval 1.34×10−6<B(B0→X(3872)K0,X→J/ψπ+π−)<10.3×10−6 and the branching fraction B(B−→X(3872)K−,X→J/ψπ+π−)=(10.1±2.5±1.0)×10−6. We observe a (2.7±1.3±0.2)MeV/c2 mass difference of the X(3872) produced in the two decay modes. Furthermore, we search for the Y(4260) in B decays and set the 95% C.L. upper limit B(B−→Y(4260)K−,Y(4260)→J/ψπ+π−)<2.9×10−5.Received 21 July 2005DOI:https://doi.org/10.1103/PhysRevD.73.011101©2006 American Physical Society

A search for charmonium and other new states is performed in a study of exclusive initial-state-radiation production of D¯¯¯D events from electron-positron annihilations at a center-of-mass energy of 10.58 GeV. The data sample corresponds to an integrated luminosity of 384 fb−1 and was recorded by the BABAR experiment at the PEP-II storage ring. The D¯¯¯D mass spectrum shows clear evidence of the ψ(3770) plus other structures near 3.9, 4.1, and 4.4 GeV/c2. No evidence for Y(4260)→D¯¯¯D is observed, leading to an upper limit of B(Y(4260)→D¯¯¯D)/B(Y(4260)→J/ψπ+π−)<1.0 at 90% confidence level.Received 6 October 2007DOI:https://doi.org/10.1103/PhysRevD.76.111105©2007 American Physical Society

The cross section and tensor analysing power t20 of the dd → 4Heη reaction have been measured at six c.m. momenta, 10 ⩽ pη ⩽ 90 MeV/c. The threshold value of t20 is consistent with 12, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd → 3Heη case, strongly suggests the existence of a quasi-bound state in the η4He system and simple optical model fits tentatively indicate that this might also be the case for η3He.

We search for a charged partner of the X(3872) in the decay B --&gt; X- K, X- --&gt; J/psi pi- pi0, using 234 million BBbar events collected at the Y(4S) resonance with the BaBar detector at the PEP-II e+e- asymmetric-energy storage ring. The resulting product branching fraction upper limits are BR(B0 --&gt; X- K+, X- --&gt; J/psi pi- pi0) &lt; 5.4 x 10(-6) and BR(B- --&gt; X- K0bar,X- --&gt; J/psi pi- pi0) &lt; 22 x 10(-6) at the 90% confidence level.

The mass m(eta(c)) and total width Gamma(eta(c))(tot) of the eta(c) meson have been measured in two-photon interactions at the SLAC e(+)e(-) asymmetric B Factory with the BABAR detector. With a sample of approximately 2500 reconstructed eta(c)-->K(0)(S)K+/-pi(-/+) decays in 88 fb(-1) of data, the results are m(eta(c))=2982.5+/-1.1(stat)+/-0.9(syst) MeV/c(2) and Gamma(eta(c))(tot)=34.3+/-2.3(stat)+/-0.9(syst) MeV/c(2). Using the same decay mode, a second resonance with 112+/-24 events is observed with a mass of 3630.8+/-3.4(stat)+/-1.0(syst) MeV/c(2) and width of 17.0+/-8.3(stat)+/-2.5(syst) MeV/c(2). This observation is consistent with expectations for the eta(c)(2S) state.

We present results on $B\to J/ψ\xspace Kπ$ decays using $e^+e^-$ annihilation data collected with the BABAR detector at the $Υ(4S)$ resonance. The detector is located at the PEP-II asymmetric-energy storage ring facility at the Stanford Linear Accelerator Center. Using approximately 88 million $B\bar{B}$ pairs, we measure the decay amplitudes for the flavor eigenmodes and observe strong-phase differences indicative of final-state interactions with a significance of 7.6 standard deviations. We use the interference between the $Kπ$ $S$-wave and $P$-wave amplitudes in the region of the $K^*(892)$ to resolve the ambiguity in the determination of these strong phases. We then perform an ambiguity-free measurement of $\cos2β$ using the angular and time-dependent asymmetry in $B\to J/ψ\xspace K^{*0}(K_S^0π^0$) dec With $\sin 2 β$ fixed at its measured value and $\cos 2 β$ treated as an in we find $\cos 2β=2.72_{-0.79}^{+0.50}\mathrm{(stat)} \pm 0.27\mathrm{(syst)}$, de sign of $\cos 2β$ to be positive at 86% CL.

We present a measurement of the branching fraction and photon-energy spectrum for the decay B→Xsγ using data from the BABAR experiment. The data sample corresponds to an integrated luminosity of 210 fb−1, from which approximately 680 000 B¯¯¯B events are tagged by a fully reconstructed hadronic decay of one of the B mesons. In the decay of the second B meson, an isolated high-energy photon is identified. We measure B(B→Xsγ)=(3.66±0.85stat±0.60syst)×10−4 for photon energies Eγ above 1.9 GeV in the B rest frame. From the measured spectrum we calculate the first and second moments for different minimum photon energies, which are used to extract the heavy-quark parameters mb and μ2π. In addition, measurements of the direct CP asymmetry and isospin asymmetry are presented.Received 29 November 2007DOI:https://doi.org/10.1103/PhysRevD.77.051103©2008 American Physical Society

With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar. We measure a branching fraction Br(B+ --> p pbar K+)=(6.7+/-0.5+/-0.4)x10^{-6}. An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level.

We present a study of excited charm-strange baryon states produced in $e^+e^-$ annihilations at or near a center-of-mass energy of $10.58\mathrm{Ge\kern -0.1em V}$, in a data sample with an integrated luminosity of $384 fb^{-1}$ recorded with the BABAR detector at the PEP-II $e^+e^-$ storage rings at the Stanford Linear Accelerator Center. We study strong decays of charm-strange baryons to $\Lambda_c^+K^0_{\scriptscriptstyle S}$, $\Lambda_c^+K^-$, $\Lambda_c^+K^-\pi^+$, $\Lambda_c^+K^0_{\scriptscriptstyle S}\pi^-$, $\Lambda_c^+K^0_{\scriptscriptstyle S}\pi^-\pi^+$, and $\Lambda_c^+K^-\pi^+\pi^-$. This study confirms the existence of the states $\Xi_c(2980)^+$, $\Xi_c(3077)^+$, and $\Xi_c(3077)^0$, with a more accurate determination of the $\Xi_c(2980)^+$ mass and width. We also present evidence for two new states, $\Xi_c(3055)^+$ and $\Xi_c(3123)^+$, decaying through the intermediate resonant modes $\Sigma_c(2455)^{++}K^-$ and $\Sigma_c(2520)^{++}K^-$, respectively. For each of these baryons, we measure the yield in each final state, determine the statistical significance, and calculate the product of the production cross-section and branching fractions. We also measure the masses and widths of these excited charm-strange baryons.

We study the two-body decays of B^\pm mesons to K^\pm and a charmonium state, X_{c\bar c}, in a sample of 210.5 fb^{-1} of data from the BaBar experiment. We perform measurements of absolute branching fractions BR(B^\pm --> K^\pm X_{c\bar c}) using a missing mass technique, and report several new or improved results. In particular, the upper limit BR(B^\pm --> K^\pm X(3872))<3.2 10^-4 at 90% CL and the inferred lower limit BR(X(3872) --> J/\psi\pi^+\pi^-)>4.2% will help in understanding the nature of the recently discovered X(3872).

Using a data sample corresponding to an integrated luminosity of 342 fb−1 collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass energy near 10.58 GeV, we measure B(τ−→π−π−π+ντ(ex.KS0))=(8.83±0.01±0.13)%, B(τ−→K−π−π+ντ(ex.KS0))=(0.273±0.002±0.009)%, B(τ−→K−π−K+ντ)=(0.1346±0.0010±0.0036)%, and B(τ−→K−K−K+ντ)=(1.58±0.13±0.12)×10−5, where the uncertainties are statistical and systematic, respectively. These include significant improvements over previous measurements and a first measurement of B(τ−→K−K−K+ντ) in which no resonance structure is assumed. We also report a first measurement of B(τ−→ϕπ−ντ)=(3.42±0.55±0.25)×10−5, a new measurement of B(τ−→ϕK−ντ)=(3.39±0.20±0.28)×10−5 and a first upper limit on B(τ−→K−K−K+ντ(ex.ϕ)).Received 19 July 2007DOI:https://doi.org/10.1103/PhysRevLett.100.011801©2008 American Physical Society

We measure CP-violating asymmetries of neutral charmed mesons in the modes D0 --> K- K+ and D0 --> pi- pi+ with the highest precision to date by using D0 --> K- pi+ decays to correct detector asymmetries. An analysis of 385.8 fb-1 of data collected with the BaBar detector yields values of aCP(KK) = (0.00 +/- 0.34 (stat.) +/- 0.13 (syst.))% and aCP(pipi) = (-0.24 +/- 0.52 (stat.) +/- 0.22 (syst.))%, which agree with Standard Model predictions.

We present a search for the decay ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu}$ using $383\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the BABAR detector at the SLAC PEP-II $B$ Factory. We select a sample of events with one completely reconstructed tag $B$ in a hadronic decay mode (${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{(*)0}{X}^{\ensuremath{-}}$), and examine the rest of the event to search for a ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu}$ decay. We identify the $\ensuremath{\tau}$ lepton in the following modes: ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\overline{\ensuremath{\nu}}$, and ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}\overline{\ensuremath{\nu}}$. We find a $2.2\ensuremath{\sigma}$ excess in data and measure a branching fraction of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu})=({1.8}_{\ensuremath{-}0.8}^{+0.9}(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.4(\mathrm{bkg}.\text{ }\mathrm{syst}.)\ifmmode\pm\else\textpm\fi{}0.2(\mathrm{other}\text{ }\mathrm{syst}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. We calculate the product of the $B$ meson decay constant ${f}_{B}$ and $|{V}_{ub}|$ to be ${f}_{B}\ifmmode\cdot\else\textperiodcentered\fi{}|{V}_{ub}|=({10.1}_{\ensuremath{-}2.5}^{+2.3}(\mathrm{stat}.{)}_{\ensuremath{-}1.5}^{+1.2}(\mathrm{syst}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}\text{ }\text{ }\mathrm{GeV}$.

A search for the lepton-flavor-violating decay of the tau into three charged leptons has been performed using 91.5 fb−1 of data collected at an e+e−center-of-mass energy around 10.58 GeV with the BABAR detector at the SLAC storage ring PEP-II. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1–3)×10−7 at 90% confidence level.Received 8 December 2003DOI:https://doi.org/10.1103/PhysRevLett.92.121801©2004 American Physical Society

Nuclear transparencies measured in exclusive incoherent ρ0 meson production from hydrogen, deuterium, carbon, calcium, and lead in muon-nucleus scattering are reported. The data were obtained with the E665 spectrometer using the Fermilab Tevatron muon beam with a mean beam energy of 470 GeV. Increases in the nuclear transparencies are observed as the virtuality of the photon increases, in qualitative agreement with the expectations of color transparency.Received 5 August 1994DOI:https://doi.org/10.1103/PhysRevLett.74.1525©1995 American Physical Society

With a sample of about 227x10(6) BB pairs recorded with the BABAR detector we perform a full angular analysis of the decay B0-->phiK(*0)(892). We make novel measurements of five parameters sensitive to CP violation. We also measure the branching fraction to be (9.2+/-0.9+/-0.5)x10(-6) and determine the fractions of longitudinal and parity-odd transverse contributions as f(L)=0.52+/-0.05+/-0.02 and f( perpendicular)=0.22+/-0.05+/-0.02. The phases of the parity-even and parity-odd transverse amplitudes relative to the longitudinal amplitude are found to be phi( parallel)=2.34(+0.23)(-0.20)+/-0.05 rad and phi( perpendicular)=2.47+/-0.25+/-0.05 rad. We also observe the decay B0-->phiK(*0)(1430).

We report on a measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase γ through a Dalitz analysis of neutral D decays to KS0π−π+ in the processes B∓→D(*)K∓, D*→Dπ0, Dγ. Using a sample of 227×106 BB¯ pairs collected by the BABAR detector, we measure the amplitude ratios rB=0.12±0.08±0.03±0.04 and rB*=0.17±0.10±0.03±0.03, the relative strong phases δB=(104±45−21−24+17+16)° and δB*=(−64±41−12+14±15)° between the amplitudes A(B−→D¯(*)0K−) and A(B−→D(*)0K−), and γ=(70±31−10−11+12+14)°. The first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the Dalitz model uncertainty. The results for the strong and weak phases have a twofold ambiguity.Received 20 April 2005DOI:https://doi.org/10.1103/PhysRevLett.95.121802©2005 American Physical Society

We report the results of a search for $T$, $CP$, and $CPT$ violation in ${B}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{B}}^{0}$ mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II $B$ factory. Using a sample of $232\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs, we measure the $T$ and $CP$ violation parameter $|q/p|\ensuremath{-}1=\mathbf{(}\ensuremath{-}0.8\ifmmode\pm\else\textpm\fi{}2.7(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.9(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, and the $CPT$ and $CP$ parameters $\mathrm{Im}z=\mathbf{(}\ensuremath{-}13.9\ifmmode\pm\else\textpm\fi{}7.3(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}3.2(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $\ensuremath{\Delta}\ensuremath{\Gamma}\ifmmode\times\else\texttimes\fi{}\mathrm{Re}z=\mathbf{(}\ensuremath{-}7.1\ifmmode\pm\else\textpm\fi{}3.9(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2.0(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$. The statistical correlation between the measurements of $\mathrm{Im}z$ and $\ensuremath{\Delta}\ensuremath{\Gamma}\ifmmode\times\else\texttimes\fi{}\mathrm{Re}z$ is 76%.

We report a study of the processes e+e- -> eta gamma and e+e- -> etaprime gamma at a center-of-mass energy of 10.58 GeV, using a 232 fb^-1 data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20+6-5 eta gamma and 50+8-7 etaprime gamma events over small backgrounds, and measure the cross sections sigma(e+e- -> eta gamma) =4.5+1.2-1.1(stat)+-0.3(sys) fb and sigma(e+e- -> etaprime gamma)=5.4+-0.8(stat)+-0.3(sys) fb. The corresponding transition form factors at q^2 = 112 GeV^2 are q^2|F_eta(q^2)|=0.229+-0.030+-0.008 GeV, and q^2|F_etaprime(q^2)|=0.251+-0.019+-0.008 GeV, respectively.

We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cutoffs on the electron energy between 0.6 and 1.5 GeV. We measure the partial branching fraction to be $\mathcal{B}(\stackrel{\ensuremath{\rightarrow}}{B}\mathrm{Xe}\ensuremath{\nu}{,E}_{e}&gt;0.6\mathrm{GeV})=[10.36\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.23(\mathrm{sys}.)]%.$

We analyze the three-body charmless decay B+- -> K+-K+-K-+ using a sample of 226.0 +- 2.5 million BBbar pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B = (35.2 +- 0.9 +-1.6) x 10^{-6} and A_CP = (-1.7 +- 2.6 +- 1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-) < 2 GeV/c^2. Significant production of the f0(980) resonance, and of a spin zero state near 1.55 GeV/c^2 are required in the isobar model description of the data. The partial-wave analysis supports this observation.

We report the results of a study of the exclusive charmless semileptonic decay, B --> pi l nu, undertaken with approximately 227 million BBbar pairs collected at the Upsilon(4S) resonance with the BaBar detector. The analysis uses events in which the signal B decays are reconstructed with an innovative loose neutrino reconstruction technique. We obtain partial branching fractions in 12 bins of q2, the momentum transfer squared, from which we extract the f+(q2) form-factor shape and the total branching fraction BF(B0 --> pi l nu) = (1.46 +- 0.07(stat) +- 0.08(syst)) x 10^-4. Based on a recent unquenched lattice QCD calculation of the form factor in the range q2 > 16 GeV^2, we find the magnitude of the CKM matrix element |Vub| to be (4.1 +- 0.2(stat) +- 0.2(syst) +0.6-0.4(FF)) x 10^-3, where the last uncertainty is due to the normalization of the form factor.

Longitudinal and transverse cross sections for the reaction 4He(e, e′ p)3H were determined for missing momenta pm up to 190 MeV/c and momentum transfers q up to 829 MeV/c (at pm=90 MeV/c). “Experimental” spectral functions were obtained; the transverse one exhibits the free nucleon q-dependence at fixed pm and agrees with microscopic theories; the longitudinal spectral function is low by 30%.

We report observations of CP violation in the decays B(0) --> K(+)pi(-) and B(0) --> pi(+)pi(-) in a sample of 383 x 10(6) Upsilon(4S) --> BB[over] events. We find 4372+/-82 B(0) --> K(+)pi(-) decays and measure the direct CP-violating charge asymmetry A(Kpi) = -0.107+/-0.018(stat)(-0.004)(+0.007)(syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample, we find 1139+/-49 B(0) --> pi(+)pi(-) decays and measure the CP-violating asymmetries S(pipi) = -0.60+/-0.11(stat)+/-0.03(syst) and C(pipi) = -0.21+/-0.09(stat)+/-0.02(syst). CP conservation in B(0) --> pi(+)pi(-) (S(pipi) = C(pipi) = 0) is excluded at a confidence level 1-C.L. = 8 x 10(-8), corresponding to 5.4 standard deviations.

The photon spectrum in B→Xsγ decay, where Xs is any strange hadronic state, is studied using a data sample of 88.5×106 e+e−→Υ(4S)→B¯¯¯B decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, ΔB(B→Xsγ)=(3.67±0.29(stat)±0.34(syst)±0.29(model))×10−4, the first moment ⟨Eγ⟩=2.288±0.025±0.017±0.015 GeV, and the second moment ⟨E2γ⟩=0.0328±0.0040±0.0023±0.0036 GeV2 are measured for the photon energy range 1.9 GeV<Eγ<2.7 GeV. They are also measured for narrower Eγ ranges. The moments are then fit to recent theoretical calculations to extract the heavy quark expansion parameters mb and μ2π and to extrapolate the partial branching fraction to Eγ>1.6 GeV. In addition, the direct CP asymmetry ACP(B→Xs+dγ) is measured to be −0.110±0.115(stat)±0.017(syst).Received 26 July 2006DOI:https://doi.org/10.1103/PhysRevLett.97.171803©2006 American Physical Society

The shape of the hadronic form factor f+(q2) in the decay D0 --> K- e+ nue has been measured in a model independent analysis and compared with theoretical calculations. We use 75 fb(-1) of data recorded by the BABAR detector at the PEPII electron-positron collider. The corresponding decay branching fraction, relative to the decay D0 --> K- pi+, has also been measured to be RD = BR(D0 --> K- e+ nue)/BR(D0 --> K- pi+) = 0.927 +/- 0.007 +/- 0.012. From these results, and using the present world average value for BR(D0 --> K- pi+), the normalization of the form factor at q2=0 is determined to be f+(0)=0.727 +/- 0.007 +/- 0.005 +/- 0.007 where the uncertainties are statistical, systematic, and from external inputs, respectively.

We report results of a search for CPT and Lorentz violation in B0−¯¯¯B0 oscillations using inclusive dilepton events from 232×106 Υ(4S)→B¯¯¯B decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8σ significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth’s sidereal frequency and extract values for the quantities Δaμ in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 yr−1 to 2.1 solar day−1 are also compatible with no signal.Received 19 November 2007DOI:https://doi.org/10.1103/PhysRevLett.100.131802©2008 American Physical Society

We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element $|{V}_{cb}|$ and of the parameters ${\ensuremath{\rho}}^{2}$, ${R}_{1}(1)$, and ${R}_{2}(1)$, which fully characterize the form factors for the ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ decay in the framework of heavy-quark effective field theory. The results, based on a selected sample of about 52 800 ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ decays, recorded by the BABAR detector, are ${\ensuremath{\rho}}^{2}=1.157\ifmmode\pm\else\textpm\fi{}0.094\ifmmode\pm\else\textpm\fi{}0.027$, ${R}_{1}(1)=1.327\ifmmode\pm\else\textpm\fi{}0.131\ifmmode\pm\else\textpm\fi{}0.043$, ${R}_{2}(1)=0.859\ifmmode\pm\else\textpm\fi{}0.077\ifmmode\pm\else\textpm\fi{}0.021$, and $\mathcal{F}(1)|{V}_{cb}|=(34.7\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. The first error is the statistical and the second is the systematic uncertainty. Combining these measurements with the previous BABAR measurement of the form factors, which employs a different fit technique on a partial sample of the data, we improve the statistical precision of the result, ${\ensuremath{\rho}}^{2}=1.191\ifmmode\pm\else\textpm\fi{}0.048\ifmmode\pm\else\textpm\fi{}0.028$, ${R}_{1}(1)=1.429\ifmmode\pm\else\textpm\fi{}0.061\ifmmode\pm\else\textpm\fi{}0.044$, ${R}_{2}(1)=0.827\ifmmode\pm\else\textpm\fi{}0.038\ifmmode\pm\else\textpm\fi{}0.022$, and $\mathcal{F}(1)|{V}_{cb}|=(34.4\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}1.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. Using lattice calculations for the axial form factor $\mathcal{F}(1)$, we extract $|{V}_{cb}|=(37.4\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}1.2{\ifmmode\pm\else\textpm\fi{}}_{1.4}^{1.2})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, where the third error is due to the uncertainty in $\mathcal{F}(1)$. We also present a measurement of the exclusive branching fraction, $\mathcal{B}=(4.69\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.34)%$.

The charge asymmetry in the production of top quark and antiquark pairs is measured in proton-proton collisions at a center-of-mass energy of 8 TeV. The data, corresponding to an integrated luminosity of 19.6 inverse femtobarns, were collected by the CMS experiment at the LHC. Events with a single isolated electron or muon, and four or more jets, at least one of which is likely to have originated from hadronization of a bottom quark, are selected. A template technique is used to measure the asymmetry in the distribution of differences in the top quark and antiquark absolute rapidities. The measured asymmetry is A[c,y] = [0.33 +/- 0.26 (stat) +/- 0.33 (syst)]%, which is the most precise result to date. The results are compared to calculations based on the standard model and on several beyond-the-standard-model scenarios.

We present evidence for the flavor-changing neutral current decay B-->K*l+l- and a measurement of the branching fraction for the related process B-->K l+l-, where l+l- is either an epsilon+epsilon- or a mu+mu- pair. These decays are highly suppressed in the standard model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123 x 10(6) Upsilon(4S)-->B(-)B decays collected with the BABAR detector at the SLAC PEP-II epsilon+epsilon- storage ring. Averaging over K(*) isospin and lepton flavor, we obtain the branching fractions B(B-->Kl+l-)=(0.65(+0.14)(-0.13)+/-0.04)x10(-6) and B(B-->K*l+l-)=(0.88(+0.33)(-0.29)+/-0.10)x10(-6), where the uncertainties are statistical and systematic, respectively. The significance of the B-->Kl+l- signal is over 8sigma, while for B-->K*l+l- it is 3.3sigma.

We determine the inclusive B→Xcℓν branching fraction, Bcℓν, the Cabibbo-Kobayashi-Maskawa matrix element |Vcb|, and other heavy-quark parameters from a simultaneous fit to moments of the hadronic-mass and lepton-energy distributions in semileptonic B-meson decays, measured as a function of the lower limit on the lepton energy, using data recorded with the BABAR detector. Using heavy-quark expansions (HQEs) to order 1/m3b, we extract Bceν=(10.61±0.16exp±0.06HQE)% and ∣∣Vcb∣∣=(41.4±0.4exp±0.4HQE±0.6th)×10−3. The stated errors refer to the experimental, HQE, and additional theoretical uncertainties.Received 12 April 2004DOI:https://doi.org/10.1103/PhysRevLett.93.011803©2004 American Physical Society

We report the observation of the $B$ meson decay $B^\pm\to J/\psi \eta K^\pm$ and evidence for the decay $B^0\to J/\psi \eta K^0_S$, using {90} million $BBbar$ events collected at the $\ensuremath{\Upsilon{(4S)}}\xspace$ resonance with the $BaBar$ detector at the PEP-II $e^+ e^-$ asymmetric-energy storage ring. We obtain branching fractions of $\cal{B}$$(B^\pm\to J/\psi \eta K^{\pm}$)=$(10.8\pm 2.3(\rm{stat.})\pm 2.4(\rm{syst.}))\times 10^{-5}$ and $\cal{B}$$(B^0\to J/\psi\eta K_{\rm{S}}^{0}$)=$(8.4\pm 2.6(\rm{stat.})\pm 2.7(\rm{syst.}))\times 10^{-5}$. We search for the new narrow mass state, the X(3872), recently reported by the Belle Collaboration, in the decay $B^\pm\to X(3872)K^\pm, X(3872)\to \jpsi \eta$ and determine an upper limit of $\cal{B}$$(B^\pm \to X(3872) K^\pm \to \jpsi \eta K^\pm$) $<7.7\times 10^{-6}$ at 90% C.L.

The inclusive production of charmonium mesons in B meson decay has been studied in a 20.3 ${\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ data set collected by the BABAR experiment operating at the $\ensuremath{\Upsilon}(4S)$ resonance. Branching fractions have been measured for the inclusive production of the charmonium mesons $J/\ensuremath{\psi},$ $\ensuremath{\psi}(2S),$ ${\ensuremath{\chi}}_{c1},$ and ${\ensuremath{\chi}}_{c2}.$ The branching fractions are also presented as a function of the center-of-mass momentum of the mesons and of the helicity of the $J/\ensuremath{\psi}.$

The branching fractions of the decays B0→K*0γ and B+→K*+γ are measured using a sample of 88×106BB¯ events collected with the BABAR detector at the PEP-II asymmetric-energy e+e− collider. We find B(B0→K*0γ)=[3.92±0.20(stat)±0.24(syst)]×10−5, B(B+→K*+γ)=[3.87±0.28(stat)±0.26(syst)]×10−5. Our measurements also constrain the direct CP asymmetry to be −0.074<A(B→K*γ)<0.049 and the isospin asymmetry to be −0.046<Δ0−<0.146, both at the 90% confidence level.Received 30 June 2004DOI:https://doi.org/10.1103/PhysRevD.70.112006©2004 American Physical Society

We report observations of the $b\ensuremath{\rightarrow}d$ penguin-dominated decays ${B}^{+}\ensuremath{\rightarrow}{\overline{K}}^{0}{K}^{+}$ and ${B}^{0}\ensuremath{\rightarrow}{K}^{0}{\overline{K}}^{0}$ in $316\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ collision data collected with the BABAR detector. We measure the branching fractions $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\overline{K}}^{0}{K}^{+})=(1.61\ifmmode\pm\else\textpm\fi{}0.44\ifmmode\pm\else\textpm\fi{}0.09)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{K}^{0}{\overline{K}}^{0})=(1.08\ifmmode\pm\else\textpm\fi{}0.28\ifmmode\pm\else\textpm\fi{}0.11)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and the $CP$-violating charge asymmetry ${\mathcal{A}}_{CP}({\overline{K}}^{0}{K}^{+})=0.10\ifmmode\pm\else\textpm\fi{}0.26\ifmmode\pm\else\textpm\fi{}0.03$. Using a vertexing technique previously employed in several analyses of all-neutral final states containing kaons, we report the first measurement of time-dependent $CP$-violating asymmetries in ${B}^{0}\ensuremath{\rightarrow}{K}_{S}^{0}{K}_{S}^{0}$, obtaining $S=\ensuremath{-}{1.28}_{\ensuremath{-}0.73\ensuremath{-}0.16}^{+0.80+0.11}$ and $C=\ensuremath{-}0.40\ifmmode\pm\else\textpm\fi{}0.41\ifmmode\pm\else\textpm\fi{}0.06$. We also report improved measurements of the branching fraction $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\pi}}^{+})=(23.9\ifmmode\pm\else\textpm\fi{}1.1\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $CP$-violating charge asymmetry ${\mathcal{A}}_{CP}({K}^{0}{\ensuremath{\pi}}^{+})=\ensuremath{-}0.029\ifmmode\pm\else\textpm\fi{}0.039\ifmmode\pm\else\textpm\fi{}0.010$.

We present measurements of the branching fractions and charge asymmetries (where appropriate) of two-body B decays to ${\ensuremath{\eta}}^{(\ensuremath{'})}{K}^{*},$ ${\ensuremath{\eta}}^{(\ensuremath{'})}\ensuremath{\rho},$ ${\ensuremath{\eta}}^{(\ensuremath{'})}{\ensuremath{\pi}}^{0},$ $\ensuremath{\omega}{\ensuremath{\pi}}^{0},$ and $\ensuremath{\varphi}{\ensuremath{\pi}}^{0}.$ The data were recorded with the BABAR detector at PEP-II and correspond to $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs produced in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation through the $\ensuremath{\Upsilon}(4S)$ resonance. We find significant signals for two decay modes and measure the branching fractions $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{*+})=(25.6\ifmmode\pm\else\textpm\fi{}4.0\ifmmode\pm\else\textpm\fi{}2.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{*0})=(18.6\ifmmode\pm\else\textpm\fi{}2.3\ifmmode\pm\else\textpm\fi{}1.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ where the first error is statistical and the second systematic. We also find evidence with significance 3.5\ensuremath{\sigma} for a third decay mode and measure $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\rho}}^{+})=(9.2\ifmmode\pm\else\textpm\fi{}3.4\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}.$ For other channels, we set 90% C.L. upper limits of $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\rho}}^{0})&lt;1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{*+})&lt;14\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{*0})&lt;7.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\rho}}^{+})&lt;22\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\rho}}^{0})&lt;4.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{0})&lt;2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\pi}}^{0})&lt;3.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{0})&lt;1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ and $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\varphi}{\ensuremath{\pi}}^{0})&lt;1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}.$ For self-flavor-tagging modes with significant signals, the time-integrated charge asymmetries are ${\mathcal{A}}_{\mathrm{ch}}(\ensuremath{\eta}{K}^{*+})=+0.13\ifmmode\pm\else\textpm\fi{}0.14\ifmmode\pm\else\textpm\fi{}0.02$ and ${\mathcal{A}}_{\mathrm{ch}}(\ensuremath{\eta}{K}^{*0})=+0.02\ifmmode\pm\else\textpm\fi{}0.11\ifmmode\pm\else\textpm\fi{}0.02.$

We report a study of D∗sJ(2317)+ and DsJ(2460)+ meson production in B decays. We observe the decays B+→D(*)+sJ¯¯¯D(*)0 and B0→D(*)+sJD(*)− with the subsequent decays D∗sJ(2317)+→D+sπ0, DsJ(2460)+→D+sγ, and DsJ(2460)+→D*+sπ0. Based on a data sample of 122.1×106 B¯¯¯B pairs collected with the BABAR detector at the PEP-II B factory, we obtain branching fractions for these modes, including the previously unseen decays B→D(*)+sJD∗. In addition, we perform an angular analysis of DsJ(2460)+→D+sγ decays to test the different DsJ(2460)+ spin hypotheses.Received 11 August 2004DOI:https://doi.org/10.1103/PhysRevLett.93.181801©2004 American Physical Society

A study of the ${D}_{sJ}^{*}(2317{)}^{+}$ and ${D}_{sJ}(2460{)}^{+}$ mesons in inclusive $c\overline{c}$ production is presented using $232\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected by the BABAR experiment near $\sqrt{s}=10.6\text{ }\text{ }\mathrm{GeV}$. Final states consisting of a ${D}_{s}^{+}$ meson along with one or more ${\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, or $\ensuremath{\gamma}$ particles are considered. Estimates of the mass and limits on the width are provided for both mesons and for the ${D}_{s1}(2536{)}^{+}$ meson. A search is also performed for neutral and doubly charged partners of the ${D}_{sJ}^{*}(2317{)}^{+}$ meson.

We present results from an analysis of B0 to rho+rho- decays using 383.6 million BB-bar pairs collected by the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC. The measurements of the B0 to rho+rho- branching fraction, longitudinal polarization fraction f_L, and the CP-violating parameters S_{long} and C_{long} are: B(B0-> rho+rho-) = (25.5 +/- 2.1 (stat) +3.6/-3.9 (syst))*10^-6 f_L = 0.992 +/- 0.024 (stat) +0.026/-0.013 (syst) S_{long} = -0.17 +/- 0.20 (stat) +0.05/-0.06 (syst) C_{long} = 0.01 +/- 0.15 (stat) +/- 0.06 (syst) We determine the unitarity triangle angle alpha, using an isospin analysis of B to rhorho decays. One of the two solutions, alpha = [73.1, 117.0] degrees at 68% CL is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry based approach.

We present updated measurements of the branching fractions and CP asymmetries for B0→π0π0, B±→π±π0, and B±→K±π0. Based on a sample of 383×106 Υ(4S)→B¯¯¯B decays collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we measure B(B0→π0π0)=(1.47±0.25±0.12)×10−6, B(B±→π±π0)=(5.02±0.46±0.29)×10−6, and B(B±→K±π0)=(13.6±0.6±0.7)×10−6. We also measure the CP asymmetries Cπ0π0=−0.49±0.35±0.05, Aπ±π0=0.03±0.08±0.01, and AK±π0=0.030±0.039±0.010. Finally, we present bounds on the Cabibbo-Kobayashi-Maskawa angle α using isospin relations.Received 18 July 2007DOI:https://doi.org/10.1103/PhysRevD.76.091102©2007 American Physical Society

A search for lepton flavor violating decays of the $\tau$ lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb$^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy near 10.58 GeV by the BaBar detector at the SLAC PEP-II storage ring. No evidence of signal has been found, and upper limits on the branching fractions are set at $10^{-7}$ level.

A measurement of the τ−→K−π0ντ branching fraction has been made using 230.2 fb−1 of data recorded by the BABAR detector at the PEP-II e+e− collider, located at the Stanford Linear Accelerator Center (SLAC), at a center-of-mass energy √s close to 10.58 GeV. We measure B(τ−→K−π0ντ)=(0.416±0.003(stat)±0.018(syst))%.Received 18 July 2007DOI:https://doi.org/10.1103/PhysRevD.76.051104©2007 American Physical Society

We present a measurement of the inclusive electron spectrum in charmless semileptonic B decays near the kinematic limit for B->X_c e\nu transitions, using a sample of 88 million Upsilon(4S) decays recorded by the BABAR detector. Partial branching fraction measurements are performed in five overlapping intervals of the electron momentum. For the interval of 2.0-2.6 GeV/c we obtain \Delta Br(B->X_u e\nu) = (0.572+-0.041(stat)+-0.065(syst))x10^{-3}. Combining this result with shape function parameters extracted from BABAR measurements of moments of the inclusive photon spectrum in B->X_s+gamma decays and moments of the hadron mass and lepton energy spectra in B->X_c l\nu decays we determine |V_{ub}|=((4.44+-0.25(exp) ^{+0.42}_{-0.38}(SF)+-0.22(theory))x10^{-3}. Here the first error represents the combined statistical and systematic experimental uncertainties of the partial branching fraction measurement, the second error refers to the uncertainty of the determination of the shape function parameters, and the third error is due to theoretical uncertainties in the QCD calculations.

We report measurements of B-meson decays into two- and three-body final states containing two charmed baryons using a sample of 230 million Y(4S) -> B Bbar decays. We find significant signals in two modes, measuring branching fractions BF(B^- -> \Lambda_c^+ \Lambda_c^- K^-) = (1.14 +- 0.15 +- 0.17 +- 0.60) x 10^{-3} and BF(B^- -> \Xi_c^0 \Lambda_c^-) x BF(\Xi_c^0 -> \Xi^- \pi^+) = (2.08 +- 0.65 +- 0.29 +- 0.54) x 10^{-5}, where the uncertainties are statistical, systematic, and from the branching fraction BF(\Lambda_c^+ -> p K^- \pi^+), respectively. We also set upper limits at the 90% confidence level on two other modes: BF(B0bar -> \Xi_c^+ \Lambda_c^-) x BF(\Xi_c^+ -> \Xi^- \pi^+ \pi^+) < 5.6 x 10^{-5} and BF(B0bar -> \Lambda_c^+ \Lambda_c^- K0bar) < 1.5 x 10^{-3}. We observe structure centered at an invariant mass of 2.93 GeV/c^2 in the \Lambda_c^+ K^- mass distribution of the decay B^- -> \Lambda_c^+ \Lambda_c^- K^-.

A measurement of the time-integrated $CP$ asymmetry in the Cabibbo-suppressed decay $D^0\rightarrow K^-K^+$ is performed using pp collision data, corresponding to an integrated luminosity of 3fb$^{-1}$, collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The flavour of the charm meson at production is determined from the charge of the pion in $D^{*+}\rightarrow D^0 π^+$ and $D^{*-}\rightarrow \bar{D^0} π^-$ decays. The time-integrated $CP$ asymmetry $A_{CP}(K^-K^+)$ is obtained assuming negligible $CP$ violation in charm mixing and in Cabibbo-favoured $D^0\rightarrow K^-π^+$, $D^+\rightarrow K^-π^+π^+$ and $D^+\rightarrow \bar{K^0}π^+$ decays used as calibration channels. It is found to be $A_{CP}(K^-K^+)=(0.14\pm0.15(stat)\pm0.10(syst))\%$. A combination of this result with previous LHCb measurements yields $A_{CP}(K^-K^+)=(0.04\pm0.12(stat)\pm0.10(syst))\%$, $A_{CP}(π^-π^+)=(0.07\pm0.14(stat)\pm0.11(syst))\%$. These are the most precise measurements from a single experiment. The result for $A_{CP}(K^-K^+)$ is the most precise determination of a time-integrated $CP$ asymmetry in the charm sector to date, and neither measurement shows evidence of CP asymmetry.

The diffractive production of ρ0(770 @#@) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV2 < Q2 < 20 GeV2 and 20 GeV < ? < 420 GeV. The data were obtained in the Fermilab fixed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q2, x and ? dependence of the cross section, on the shape of the ρ+ρt - mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the ρ0(770). The cross section for diffractive production of ρ0 by virtual photons on protons depends mainly on Q2. At fixed Q2, no significant dependence on x or ? is observed. The extrapolation to Q2 = 0 yields a photoproduction cross section of (10.30 ± 0.33) μb. The slope of the t′ distribution has a value of (7.0 ± 0.2) GeV−2, with a tendency to decrease as Q2 increases. The production and decay angular distributions of the ρ0 depend strongly on Q2 and are consistent with s-channel helicity conservation. The ratio R = σ l /σ t deduced from the decay angular distributions rises strongly with Q2, passing the value of 1 at Q2 ≈ 2 GeV2.

The polarization transfer κ0 and the tensor analyzing power T20 for the 1Hdp)d reaction have been measured up to an internal momentum of k = 0.58 GeV/c. Comparison of the same observables obtained in recent studies for 1Hdp)d reaction, as a function of k, show different behavior. However the data from these two reactions are almost identical when compared in T20 versus κ0 correlation plots. We discuss similarities and differences observed in the two reactions.

We present measurements of branching fractions and CP-violating asymmetries in B0→ρ±π∓ and B0→ρ−K+ decays. The results are obtained from a data sample of 88.9×106 Υ(4S)→B¯¯¯B decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a time-dependent maximum likelihood fit we measure the branching fractions B(B0→ρ±π∓)=[22.6±1.8 (stat)±2.2 (syst)]×10−6 and B(B0→ρ−K+)=(7.3 +1.3 −1.2±1.3)×10−6, and the CP-violating charge asymmetries AρπCP=−0.18±0.08±0.03 and AρKCP=0.28±0.17±0.08, the direct CP violation parameter Cρπ=0.36±0.18±0.04 and the mixing-induced CP violation parameter Sρπ=0.19±0.24±0.03, and the dilution parameters ΔCρπ=0.28 +0.18 −0.19±0.04 and ΔSρπ=0.15±0.25±0.03.Received 13 June 2003DOI:https://doi.org/10.1103/PhysRevLett.91.201802©2003 American Physical Society

We have studied the process e+e−→μ+μ−γ at a center-of-mass energy near the Υ(4S) resonance for a μ+μ− invariant mass range near the J/ψ mass and measured the cross section σ(e+e−→J/ψγ→μ+μ−γ). The data set, corresponding to an integrated luminosity of 88.4fb−1, was collected using the BABAR detector at the SLAC PEP-II collider. From the measured cross section we extract the product Γ(J/ψ→e+e−)B(J/ψ→μ+μ−)=0.330±0.008±0.007keV. Using the world averages for B(J/ψ→μ+μ−) and B(J/ψ→e+e−), we derive the J/ψ electronic and total widths: Γ(J/ψ→e+e−)=5.61±0.20keV and Γ=94.7±4.4keV. Received 14 October 2003DOI:https://doi.org/10.1103/PhysRevD.69.011103©2004 American Physical Society

A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using 376 fb−1 of data collected at an e+e− center-of-mass energy around 10.58 GeV with the BABAR detector at the SLAC PEP-II storage rings. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (4–8)×10−8 at 90% confidence level.Received 27 August 2007DOI:https://doi.org/10.1103/PhysRevLett.99.251803©2007 American Physical Society

We present the first measurement of $\Upsilon(4S)$ decays to $\pi^+pi^-\Upsilon(1S)$ and $\pi^+pi^-\Upsilon(2S)$ based on a sample of 230$\times10^6$ $\Upsilon(4S)$ mesons collected with the BABAR detector. We measure the product branching fractions ${\cal B}(\Upsilon(4S)\to \pi^+pi^-\Upsilon(1S))\times{\cal B}(\Upsilon(1S)\to\mu^+\mu^-)=(2.23\pm0.25_{stat} \pm0.27_{sys})\times 10^{-6}$ and ${\cal B}(\Upsilon(4S)\to \pi^+pi^-\Upsilon(2S))\times{\cal B}(\Upsilon(2S)\to\mu^+\mu^-)=(1.69\pm0.26_{stat}\pm0.20_{sys})\times 10^{-6}$, from which we derive the partial widths $\Gamma(\Upsilon(4S)\to \pi^+pi^-\Upsilon(1S))=(1.8\pm0.4)$~keV and $\Gamma(\Upsilon(4S)\to \pi^+pi^-\Upsilon(2S))=(2.7\pm0.8)$~keV.

We perform the first three-dimensional measurement of the amplitudes of B→ψ(2S)K* and B→χc1K* decays and update our previous measurement for B→J/ψK*. We use a data sample collected with the BABAR detector at the PEP-II storage ring, corresponding to 232×106 BB¯ pairs. The longitudinal polarization of decays involving a JPC=1++ χc1 meson is found to be larger than that with a 1-- J/ψ or ψ(2S) meson. No direct CP-violating charge asymmetry is observed.Received 5 April 2007DOI:https://doi.org/10.1103/PhysRevD.76.031102©2007 American Physical Society

We report the observation of charmless hadronic decays of charged B mesons to the final state K+K−π+. Using a data sample of 347.5 fb−1 collected at the Υ(4S) resonance with the BABAR detector, we observe 429±43 signal events with a significance of 9.6σ. We measure the inclusive branching fraction B(B+→K+K−π+)=[5.0±0.5(stat)±0.5(syst)]×10−6. Inspection of the Dalitz plot of signal candidates shows a broad structure peaking near 1.5 GeV/c2 in the K+K− invariant mass distribution. We find the direct CP asymmetry to be consistent with zero.Received 3 August 2007DOI:https://doi.org/10.1103/PhysRevLett.99.221801©2007 American Physical Society

We present a search for the decay ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu}$ using $383\ifmmode\times\else\texttimes\fi{}{10}^{6}B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the BABAR detector at the SLAC PEP-II $B$-Factory. A sample of events with one reconstructed semileptonic $B$ decay (${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{0}\ensuremath{\ell}\ensuremath{-}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}X$) is selected, and in the recoil a search for ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu}$ is performed. The $\ensuremath{\tau}$ is identified in the following channels: ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\overline{\ensuremath{\nu}}$, and ${\ensuremath{\tau}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}\overline{\ensuremath{\nu}}$. We measure a branching fraction of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu})=(0.9\ifmmode\pm\else\textpm\fi{}0.6(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.1(\mathrm{syst}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. In the absence of a significant signal, we calculate an upper limit at the 90% confidence level of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu})&lt;1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. We calculate the product of the $B$ meson decay constant ${f}_{B}$ and $|{V}_{\mathrm{ub}}|$ to be ${f}_{B}\ifmmode\cdot\else\textperiodcentered\fi{}|{V}_{\mathrm{ub}}|=({7.2}_{\ensuremath{-}2.8}^{+2.0}(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2(\mathrm{syst}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}\text{ }\text{ }\mathrm{GeV}$.

An analytic distorted-wave Born approximation approach to Coulomb distortion effects up to (Z\ensuremath{\alpha}${)}^{2}$ terms in inclusive and exclusive quasifree scattering is proposed. Applications to $^{40}\mathrm{Ca}$ and $^{208}\mathrm{Pb}$ are discussed and a new longitudinal-transverse separation procedure is investigated. The positron cross section is studied in $^{208}\mathrm{Pb}$.

Using 230.2 fb−1 of e+e− annihilation data collected with the BABAR detector at and near the peak of the Υ(4S) resonance, 489±55 events containing the pure leptonic decay D+s→μ+νμ have been isolated in charm-tagged events. The ratio of partial widths Γ(D+s→μ+νμ)/Γ(D+s→ϕπ+) is measured to be 0.143±0.018±0.006 allowing a determination of the pseudoscalar decay constant fDs=(283±17±7±14) MeV. The errors are statistical, systematic, and from the D+s→ϕπ+ branching ratio, respectively.Received 1 August 2006DOI:https://doi.org/10.1103/PhysRevLett.98.141801©2007 American Physical Society

We perform an amplitude analysis of the decays B0→ϕK∗2(1430)0, ϕK∗(892)0, and ϕ(Kπ)0S−wave with a sample of about 384×106 B¯¯¯B pairs recorded with the BABAR detector. The fractions of longitudinal polarization fL of the vector-tensor and vector-vector decay modes are measured to be 0.853+0.061−0.069±0.036 and 0.506±0.040±0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP violation.Received 24 October 2006DOI:https://doi.org/10.1103/PhysRevLett.98.051801©2007 American Physical Society

We present a measurement of ${D}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{D}}^{0}$ mixing parameters using the ratios of lifetimes extracted from a sample of ${D}^{0}$ mesons produced through the process ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$, which decay to ${K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, ${K}^{\ensuremath{-}}{K}^{+}$, or ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. The lifetimes of the $CP$-even, Cabibbo-suppressed modes ${K}^{\ensuremath{-}}{K}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ are compared with that of the $CP$-mixed, Cabibbo-favored mode ${K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ to obtain a measurement of ${y}_{CP}$, which in the limit of $CP$ conservation corresponds to the mixing parameter $y$. The analysis is based on a data sample of $384\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected by the BABAR detector at the PEP-II asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We obtain ${y}_{CP}=[1.24\ifmmode\pm\else\textpm\fi{}0.39(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.13(\mathrm{syst})]%$, which is evidence for ${D}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{D}}^{0}$ mixing at the $3\ensuremath{\sigma}$ level, and $\ensuremath{\Delta}Y=[\ensuremath{-}0.26\ifmmode\pm\else\textpm\fi{}0.36(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.08(\mathrm{syst})]%$, where $\ensuremath{\Delta}Y$ constrains possible $CP$ violation. Combining this result with a previous BABAR measurement of ${y}_{CP}$ obtained from a separate sample of ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}^{+}$ events, we obtain ${y}_{CP}=[1.03\ifmmode\pm\else\textpm\fi{}0.33(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.19(\mathrm{syst})]%$.

We present measurements of the branching fractions for the charmless two-body decays B0→π+π− and B0→K+π−, and a search for the decay B0→K+K−. We include the effects of final-state radiation from the daughter mesons for the first time, and quote branching fractions for the inclusive processes B0→h+h'−nγ, where h and h′ are pions or kaons. The maximum value of the sum of the energies of the n undetected photons, Emaxγ, is mode-dependent. Using a data sample of approximately 227×106 Υ(4S)→B¯¯¯B decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e− collider at SLAC, we measure: B(B0→π+π−nγ;Emaxγ=150 MeV)=(5.1±0.4±0.2)×10−6, B(B0→K+π−nγ;Emaxγ=105 MeV)=(18.1±0.6±0.6)×10−6, B(B0→K+K−nγ;Emaxγ=59 MeV)<0.5×10−6(90% confidence level), where the first uncertainty is statistical and the second is systematic. Theoretical calculations can be used to extrapolate from the above measurements the nonradiative branching fractions, B0. Using one such calculation, we find: B0(B0→π+π−)=(5.5±0.4±0.3)×10−6, B0(B0→K+π−)=(19.1±0.6±0.6)×10−6, B0(B0→K+K−)<0.5×10−6(90% confidence level). Meaningful comparison between theory and experiment, as well as combination of measurements from different experiments, can be performed only in terms of these nonradiative quantities.Received 2 August 2006DOI:https://doi.org/10.1103/PhysRevD.75.012008©2007 American Physical Society

We report the results of a CP violation analysis of the decay B+/- --> D(pipipi0)K+/-, where D(pipipi0) indicates a neutral D meson detected in the final state pi+pi-pi0, excluding K_S pi0. The analysis makes use of 324 million e+e- --> BB events recorded by the BaBar experiment at the PEP-II e+e- storage ring. By analyzing the pi+pi-pi0 Dalitz plot distribution and the B+/- --> D(pipipi0)K+/- branching fraction and decay rate asymmetry, we calculate parameters related to the phase gamma of the CKM unitarity triangle. We also measure the magnitudes and phases of the components of the D0 --> pi+pi-pi0 decay amplitude.