C. Riccardi

The narrow dip observed at 1.9 GeV/c2 by the Fermilab experiment E687 in diffractive photoproduction of 3π+3π− is examined. The E687 data are refitted, a mechanism is proposed to explain why this resonance appears as a dip, and possible interpretations are discussed.

The magnetic spectrometer and charged particle tracking system used in Fermilab experiment 687 to study the photoproduction and decay of charm particles are described in detail. The photons are produced by a wideband electron beam which can operate at energies up to 600 GeV/c. The spectrometer consists of a high resolution silicon microstrip detector, a large aperture dipole magnet, proportional chambers, a second large aperture dipole, and more proportional chambers. Three multi-cell threshold Cherenkov counters provide charged particle identification. The tracking system is capable of resolving the secondary decay vertices of charm and beauty mesons and baryons from the primary interaction vertex. It also determines the invariant mass of the multibody final states of particles containing heavy quarks with excellent resolution. The particle identification system allows one to identify kaons and protons present in these final states clearly. This collection of detectors produces very clean signals for charm particles and permits one to make many cross checks of the apparatus. The performance is illustrated for a variety of charm signals. Of particular interest is a description of the tracking through the silicon microstrip detector and its use in isolating downstream decay vertices. Two complementary approaches to the reconstruction of secondary decay vertices are presented and insight is gained by comparing their strengths and weaknesses.

Using data from the FOCUS experiment we analyze the D+π− and D0π+ invariant mass distributions. We measure the D2∗0 mass MD2∗0=(2464.5±1.1±1.9)MeV/c2 and width ΓD2∗0=(38.7±5.3±2.9)MeV/c2, and the D2∗+ mass MD2∗+=(2467.6±1.5±0.76)MeV/c2 and width ΓD2∗+=(34.1±6.5±4.2)MeV/c2. We find evidence for broad structures over background in both the neutral and charged final state. If each is interpreted as evidence for a single L=1, jq=1/2 excited charm meson resonance, the masses and widths are M1/20=(2407±21±35)MeV/c2, Γ1/20=(240±55±59)MeV/c2, and M1/2+=(2403±14±35)MeV/c2, Γ1/2+=(283±24±34)MeV/c2, respectively.

Chiral symmetry and its spontaneous breaking play an important role both in the light hadron and heavy hadron systems. The chiral perturbation theory (χPT) is the low energy effective field theory of the Quantum Chromodynamics. In this work, we shall review the investigations on the chiral corrections to the properties of the heavy mesons and baryons within the framework of χPT. We will also review the scatterings of the light pseudoscalar mesons and heavy hadrons, through which many new resonances such as the Ds0∗(2317) could be understood.Moreover, many new hadron states were observed experimentally in the past decades. A large group of these states is near-threshold resonances, such as the charged charmoniumlike Zc and Zcs states, bottomoniumlike Zb states, hidden-charm pentaquark Pc and Pcs states and the doubly charmed Tcc state, etc. They are very good candidates of the loosely bound molecular states composed of a pair of charmed (bottom) hadrons, which are very similar to the loosely bound deuteron. The modern nuclear force was built upon the chiral effective field theory (χEFT), which is the extension of the χPT to the systems with two matter fields. The long-range and medium-long-range interactions between two nucleons arise from the single- and double-pion exchange respectively, which are well constrained by the chiral symmetry and its spontaneous breaking. The short-distance interactions can be described by the low energy constants. Such a framework works very well for the nucleon–nucleon scattering and nuclei. In this work, we will perform an extensive review of the progress on the heavy hadronic molecular states within the framework of χEFT. We shall emphasize that the same chiral dynamics not only govern the nuclei and forms the deuteron, but also dictates the shallow bound states or resonances composed of two heavy hadrons.

The AEGIS experiment, currently being set up at the Antiproton Decelerator at CERN, has the objective of studying the free fall of antimatter in the Earth's gravitational field by means of a pulsed cold atomic beam of antihydrogen atoms. Both duration of free fall and vertical displacement of the horizontally emitted atoms will be measured, allowing a first test of the WEP with antimatter.

The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational interaction is of high interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics--the moiré deflectometer--for a measurement of the acceleration of slow antiprotons. The setup consists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleration of neutral antimatter.

We have performed a search for CPT violation in neutral charm meson oscillations. While flavor mixing in the charm sector is predicted to be small by the Standard Model, it is still possible to investigate CPT violation through a study of the proper time dependence of a CPT asymmetry in right-sign decay rates for D0→K−π+ and D0→K+π−. This asymmetry is related to the CPT violating complex parameter ξ and the mixing parameters x and y: ACPT∝(Reξ)y−(Imξ)x. Our 95% confidence level limit is −0.0068<(Reξ)y−(Imξ)x<0.0234. Within the framework of the Standard Model Extension incorporating general CPT violation, we also find 95% confidence level limits for the expressions involving coefficients of Lorentz violation of (−2.8<N(x,y,δ)(Δa0+0.6ΔaZ)<4.8)×10−16 GeV, (−7.0<N(x,y,δ)ΔaX<3.8)×10−16 GeV, and (−7.0<N(x,y,δ)ΔaY<3.8)×10−16 GeV, where N(x,y,δ) is the factor which incorporates mixing parameters x, y and the doubly Cabibbo-suppressed to Cabibbo-favored relative strong phase δ.

Using a high statistics sample of photoproduced charm particles from the FOCUS experiment at Fermilab, we compare the lifetimes of neutral D mesons decaying via D0 to K- pi+ and K- K+ to measure the lifetime differences between CP even and CP odd final states. These measurements bear on the phenomenology of D0 - D0bar mixing. If the D0 to K-pi+ is an equal mixture of CP even and CP odd eigenstates, we measure yCP = 0.0342 \pm 0.0139 \pm 0.0074.

Using a large sample of charm semileptonic decays collected by the FOCUS photoproduction experiment at Fermilab, we present evidence for a small, even spin K−π+ amplitude that interferes with the dominant K̄∗0 component in the D+→K−π+μ+ν final state. Although this interference significantly distorts the D+→K−π+μ+ν decay angular distributions, the new amplitude creates only a very small distortion to the observed kaon pion mass distribution when integrated over the other kinematic variables describing the decay. Our data can be described by K̄∗0 interference with either a constant amplitude or broad spin zero resonance.

Analysis of three D → Kππ Dalitz plots is presented using data collected by the Fermilab high energy photoproduction experiment E687. Our data are fit to a model consisting of a sum of Breit-Wigner amplitudes for the intermediate two-body resonant decay modes and a constant term for the nonresonant contribution. We extract branching fractions and relative phases and compare them to the results obtained in other experiments. Although this model qualitatively reproduces many features of our data, statistically significant discrepancies are observed in some of our fits.

FOCUS results from Dalitz plot analyses of D+s and D+ to π+π−π+ are presented. The K-matrix formalism is applied to charm decays for the first time, which allows us to fully exploit the already existing knowledge coming from light-meson spectroscopy experiments. In particular all the measured dynamics of the S-wave ππ scattering, characterized by broad/overlapping resonances and large non-resonant background, can be properly included. This Letter studies the extent to which the K-matrix approach is able to reproduce the observed Dalitz plot and thus help us to understand the underlying dynamics. The results are discussed along with their possible implications for the controversial σ meson.

The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. We will measure the Earth's gravitational acceleration g¯ with antihydrogen atoms being launched in a horizontal vacuum tube and traversing a moiré deflectometer. We intend to use a position sensitive device made of nuclear emulsions (combined with a time-of-flight detector such as silicon μ-strips) to measure precisely their annihilation points at the end of the tube. The goal is to determine g¯ with a 1% relative accuracy. In 2012 we tested emulsion films in vacuum and at room temperature with low energy antiprotons from the CERN antiproton decelerator. First results on the expected performance for AEgIS are presented.

We describe the algorithm used to identify charged tracks in the fixed-target charm-photoproduction experiment FOCUS.

Using a large sample of D0→K−μ+ν and D0→π−μ+ν decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of the q2 dependence for the f+(q2) form factor. These measured f+(q2) form factors are fit to common parameterizations such as the pole dominance form and compared to recent unquenched Lattice QCD calculations. We find mpole=1.93±0.05±0.03GeV/c2 for D0→K−μ+ν and mpole=1.91−0.15+0.30±0.07GeV/c2 for D0→π−μ+ν and f−(K)(0)/f+(K)(0)=−1.7−1.4+1.5±0.3.

Using data collected by the high-energy photoproduction experiment FOCUS at Fermilab we performed a Dalitz plot analysis of the Cabibbo favored decay D+→K−π+π+. This study uses 53653 Dalitz-plot events with a signal fraction of ∼97%, and represents the highest statistics, most complete Dalitz plot analysis for this channel. Results are presented and discussed using two different formalisms. The first is a simple sum of Breit–Wigner functions with freely fitted masses and widths. It is the model traditionally adopted and serves as comparison with the already published analyses. The second uses a K-matrix approach for the dominant S-wave, in which the parameters are fixed by first fitting Kπ scattering data and continued to threshold by Chiral Perturbation Theory. We show that the Dalitz plot distribution for this decay is consistent with the assumption of two-body dominance of the final state interactions and the description of these interactions is in agreement with other data on the Kπ final state.

The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moir&apos;e deflectometer. The goal is to determine the gravitational acceleration with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon μ-strip detector to measure the time of flight. Nuclear emulsions can measure the annihilation vertex of antihydrogen atoms with a precision of ∼ 1–2 μm r.m.s. We present here results for emulsion detectors operated in vacuum using low energy antiprotons from the CERN antiproton decelerator. We compare with Monte Carlo simulations, and discuss the impact on the AEgIS project.

Fermilab high-energy photoproduction experiment E687 provides a high statistics sample of the decay mode D+ → K∗0μ+ν (charge conjugates are implied). Our analysis yields a branching ratio of Γ (D+ → K∗0μ+ν)Γ (D+ → K−π+π+) = 0.56±0.04±0.06. The ratios of the form factors governing the decay are measured to be Rν = 1.74 ±0.27±0.28 and R2 = 0.78±0.18±0.10, implying a polarization of ΓlΓt = 1.20±0.13 ±0.13 for the electron decay. Finally, we report new limits on the decay modes D+ → K−π+μ+ν (nonresonent) and D+ → K∗0π0μ+ν.

An observation of an excited ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$ baryon decaying to ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$, with ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$\ensuremath{\rightarrow}${\mathit{pK}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{+}$, is presented. We reconstruct 39.7\ifmmode\pm\else\textpm\fi{}8.7${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$ baryons with a mass of 340.4\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}0.3 MeV/${\mathit{c}}^{2}$ above the ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$ mass. The upper limit on the resonant branching ratio is B(${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Sigma}}}_{\mathit{c}}$${\mathrm{\ensuremath{\pi}}}^{\ifmmode\pm\else\textpm\fi{}}$)/B(${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$ ${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$)36% at the 90% confidence level.

The CMS Barrel resistive plate chambers quality tests are performed at three different sites (Bari, Pavia and Sofia), where equivalent software and hardware tools are used. Data from the first 210 detectors are available for a comprehensive analysis. The paper describes the general experimental set-up, the test procedure and the cosmic muon test results. The muon trajectory reconstruction algorithm, used for precise studies, is presented. The criteria to accept or reject a detector are also given. The CMS final-design chambers show an average efficiency greater than 95%.

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K−π+ S-wave amplitude from the decay D+→K−π+π+. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit–Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K−π+ system.

A narrow dip structure has been observed at 1.9 GeV/c2 in a study of diffractive photoproduction of the 3π+3π− final state performed by the Fermilab experiment E687.

Amplitude analyses of the D+ and Ds+ → K+K−π+ Dalitz plots are presented using data collected by the Fermilab high energy photoproduction experiment E687. Our data are fit to a model consisting of a sum of Breit-Wigner amplitudes for the intermediate two-body resonant decay modes. We extract decay fractions and relative phases. These results are used to infer new branching ratios for D+ → K+K−π+ inclusive as well as the Φπ+ and K∗(892)0K+ channels.

A novel version of the front-end electronics for the CMS Resistive Plate Chambers is described. It is based on a new front-end ASIC, designed and manufactured in the 0.8μm BiCMOS technology by Austria Mikro Systeme. The main improvements with respect to the previous version (Loddo et al., Proceedings of the Fourth International Workshop on Resistive Plate Chambers and related Detectors, Napoli, 15–16 October 1997) [1] concern the input impedance, the threshold uniformity and the timing performance. Simulation and test results will be shown, together with a brief description of the automatic test system for both front-end chip and board.

The ratio of cumulant to factorial moments of experimental multiplicity distributions has been calculated for e+e− and hh interactions in a wide range of energies. As a function of the rank it exhibits an initial steep decrease and a series of oscillations around zero. Those features cannot be reproduced by the Negative Binomial Distribution. A comparable behaviour is instead predicted in high-energy perturbative QCD. The presence of a qualitatively similar behaviour for different processes and in wide energy intervals suggests speaking of an approximate scaling of the cumulant to factorial moment ratio.

The formation of highly reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50 × 50 cm2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition, possible additional impurities as well as fluoride ions have been monitored in different gamma irradiation conditions both in open and closed loop mode. The chemical composition of the RPC electrode surface has also been analyzed using an electron microscope equipped with an EDS/X-ray.

An amplitude analysis of the D+, Ds+ → π−π+π+ Dalitz plots is presented using data collected by the Fermilab high-energy photoproduction experiment E687. The data are fitted to a model consisting of a sum of relativistic Breit-Wigner amplitudes for the intermediate two-body resonant decay modes plus a flat non-resonant contribution. From the fit we derive decay fractions and relative phases. We also present measurements of Γ(D+→π−π+π+)Γ(D+→K−π+π+) and Γ(Ds+→π−π+π+)Γ(Ds+→K−K+π+).

Using data from the FOCUS (E831) experiment, we have searched for T violation in charm meson decays using the four-body decay channels $D^0 \to K^-K^+\pi^-\pi^+$, $D^+ \to K^0_SK^+\pi^-\pi^+$, and $D^+_s \to K^0_SK^+\pi^-\pi^+$. The T violation asymmetry is obtained using triple-product correlations and assuming the validity of the CPT theorem. We find the asymmetry values to be $A_Tviol (D^0) = 0.010 \pm 0.057(stat.) \pm 0.037(syst.)$, $A_Tviol (D^+) = 0.023 \pm 0.062(stat.) \pm 0.022(syst.)$, and $A_Tviol (D^+_s) = -0.036 \pm 0.067(stat.) \pm 0.023(syst.)$. Each measurement is consistent with no T violation. New measurements of the CP asymmetries for some of these decay modes are also presented.

Using a large sample of D+ to K- pi+ mu+ nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of two semileptonic form factor ratios: rv and r2. We find rv = 1.504 \pm 0.057 \pm 0.039 and r2 = 0.875 \pm 0.049 \pm 0.064. Our form factor results include the effects of the s-wave interference discussed in a previous paper.

We present a Kπ mass spectrum analysis of the four-body semileptonic charm decay D+→K−π+μ+ν in the range of 0.65GeV/c2<mKπ<1.5GeV/c2. We observe a non-resonant contribution of 5.30±0.74−0.96+0.99% with respect to the total D+→K−π+μ+ν decay. For the K∗(892)0 resonance, we obtain a mass of 895.41±0.32−0.43+0.35MeV/c2, a width of 47.79±0.86−1.06+1.32MeV/c2, and a Blatt–Weisskopf damping factor parameter of 3.96±0.54−0.90+1.31GeV−1. We also report 90% CL upper limits of 4% and 0.64% for the branching ratios Γ(D+→K¯∗(1680)0μ+ν)Γ(D+→K−π+μ+ν) and Γ(D+→K¯0∗(1430)0μ+ν)Γ(D+→K−π+μ+ν), respectively.

We describe a silicon microstrip detector interleaved with segments of a beryllium oxide target which was used in the FOCUS photoproduction experiment at Fermilab. The detector was designed to improve the vertex resolution and to enhance the reconstruction efficiency of short-lived charm particles.

We present an analysis of the decay D0→K+π− based on FOCUS data. From a sample of 234 signal events, we find a branching ratio of Γ(D0→K+π−)Γ(D0→K−π+)=(0.429−0.061+0.063±0.027)% under the assumptions of no mixing and no CP violation. Allowing for CP violation, we find a branching ratio of (0.429±0.063±0.028)% and a CP asymmetry of 0.18±0.14±0.04. The branching ratio for the case of mixing with no CP violation is (0.381−0.163+0.167±0.092)%. We also present limits on charm mixing.

The AEgIS experiment is presently almost completely installed at CERN. It is currently taking data with antiprotons, electrons and positrons. The apparatus is designed to form a cold, pulsed beam of antihydrogen to measure the Earth's gravitational acceleration g on antimatter and to perform spectroscopy measurements. This paper describes the main features of the apparatus and shows a selected review of some achieved results.

In view of the High Luminosity LHC, the CMS Muon system will be upgraded to sustain its efficient muon triggering and reconstruction performance. Resistive Plate Chambers (RPC) are dedicated detectors for muon triggering due to their excellent timing resolution. The RPC system will be extended up to 2.4 in pseudorapidity. Before the LHC Long Shutdown 3, new RE3/1 and RE4/1 stations of the forward Muon system will be equipped with improved Resistive Plate Chambers (iRPC) having, compared to the present RPC system, a different design and geometry and 2D strip readout. This advanced iRPC geometry configuration allows the rate capability to improve and hence survive the harsh background conditions during the HL-LHC phase. Several iRPC demonstrator chambers were installed in CMS during the recently completed 2nd Long Shutdown to study the detector behaviour under real LHC conditions. This paper summarizes the iRPC project and its schedule, including the status of the iRPC production sites, details of the chamber quality control procedures and results of the commissioning of the demonstrator chambers.

In view of the High Luminosity upgrade of the CERN LHC, the forward CMS Muon spectrometer will be extended with two new stations of improved Resistive Plate Chambers (iRPC) covering the pseudorapidity range from 1.8 to 2.4. Compared to the present RPC system, the gap thickness is reduced to lower the avalanche charge, and an innovative 2D strip readout geometry is proposed. These improvements will allow iRPC detector to cope with higher background rates. A new Front-End-Board (FEB) is designed to readout iRPC signals with a threshold as low as 30 fC and an integrated Time Digital Converter with a resolution of 30 ps. In addition, the communication bandwidth is significantly increased by using optical fibers. The history, final design, certification, and calibration of this FEB are presented.

A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to search for CP violation in the Cabibbo suppressed decay modes D+→K−K+π+, D0→K−K+ and D0→π−π+. We have measured the following CP asymmetry parameters: ACP(K−K+π+)=+0.006±0.011±0.005, ACP(K−K+)=−0.001±0.022±0.015 and ACP(π−π+)=+0.048±0.039±0.025 where the first error is statistical and the second error is systematic. These asymmetries are consistent with zero with smaller errors than previous measurements.

A high-statistics sample of photoproduced charm from the FOCUS experiment has been used to search for direct CP violation in the decay rates for D+-->K(S)pi+ and D+-->K(S)K+. We have measured the following asymmetry parameters relative to D+-->K-pi+pi+: A(CP)(K(S)pi+) = (-1.6+/-1.5+/-0.9)%, A(CP)(K(S)K+) = (+6.9+/-6.0+/-1.5)%, and A(CP)(K(S)K+) = (+7.1+/-6.1+/-1.2)% relative to D+-->K(S)pi+. We have also measured the relative branching ratios and found Gamma(D+-->K(0)pi+)/Gamma(D+-->K-pi+pi+) = (30.60+/-0.46+/-0.32)%, Gamma(D+-->K(0)K+)/Gamma(D+-->K-pi+pi+) = (6.04+/-0.35+/-0.30)%, and Gamma(D+-->K(0)K+)/Gamma(D+-->K(0)pi+) = (19.96+/-1.19+/-0.96)%.

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the branching ratios of the Cabibbo-suppressed decay modes D0→π−π+ and D0→K−K+. We measured: Γ(D0→K−K+)/Γ(D0→π−π+)=2.81±0.10(stat)±0.06(syst), Γ(D0→K−K+)/Γ(D0→K−π+)=0.0993±0.0014(stat)±0.0014(syst), and Γ(D0→π−π+)/Γ(D0→K−π+)=0.0353±0.0012(stat)±0.0006(syst). These values have been combined with other experimental data to extract the ratios of isospin amplitudes and the phase shifts for the D→KK and D→ππ decay channels.

We review genetic programming principles, their application to FOCUS data samples, and use the method to study the doubly Cabibbo suppressed decay D+ -> K+ pi+ pi- relative to its Cabibbo favored counterpart, D+ -> K- pi+ pi+. We find that this technique is able to improve upon more traditional analysis methods. To our knowledge, this is the first application of the genetic programming technique to High Energy Physics data.

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter αΛc in Λc+→Λπ+ decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter A≡αΛc+αΛ¯cαΛc−αΛ¯c. We obtain αΛc=−0.78±0.16±0.19 and A=−0.07±0.19±0.24 where errors are statistical and systematic.

The AEgIS Experiment is an international collaboration based at CERN whose aim is to perform the first direct measurement of the gravitational acceleration g of antihydrogen in the gravitational field of the Earth. Cold antihydrogen will be produced with a pulsed charge exchange reaction in a cylindrical Penning trap where antiprotons will be cooled to 100mK. The cold antihydrogen will be produced in an excited Rydberg state and subsequently formed into a beam. The deflection of the antihydrogen beam will be measured by using Moiré deflectometer gratings. After being approved in late 2008, AEgIS started taking data in a commissioning phase early 2012. This report presents an overview of the AEgIS experiment, describes its current status and shows the first measurements on antiproton catching and cooling in the 5 T Penning catching trap. We will also present details on the techniques needed for the 100mK antihydrogen production, such as pulsed positronium production and its excitation with lasers.

We present evidence for the Ωc0 in a new decay mode Ωc0 → Σ+K−K−π+, for which we find 42.5 ± 8.8 events with a mass of 2699.9 ± 1.5 ± 2.5 MeV/c2. The data are from Fermilab high energy photoproduction experiment E687.

We report the measurement of masses and widths of the following L=1 charm mesons by the E687 Collaboration at Fermilab: a ${\mathit{D}}_{2}^{\mathrm{*}0}$ state of mass (width) 2453\ifmmode\pm\else\textpm\fi{}3\ifmmode\pm\else\textpm\fi{}2 (25\ifmmode\pm\else\textpm\fi{}10\ifmmode\pm\else\textpm\fi{}5) MeV/${\mathit{c}}^{2}$ decaying to ${\mathit{D}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$, a ${\mathit{D}}_{2}^{\mathrm{*}+}$ state of mass (width) 2453\ifmmode\pm\else\textpm\fi{}3\ifmmode\pm\else\textpm\fi{}2 (23\ifmmode\pm\else\textpm\fi{}9\ifmmode\pm\else\textpm\fi{}5) MeV/${\mathit{c}}^{2}$ decaying to ${\mathit{D}}^{0}$${\mathrm{\ensuremath{\pi}}}^{+}$, a ${\mathit{D}}_{1}^{0}$ state of mass (width) 2422\ifmmode\pm\else\textpm\fi{}2\ifmmode\pm\else\textpm\fi{}2 (15\ifmmode\pm\else\textpm\fi{}8\ifmmode\pm\else\textpm\fi{}4) MeV/${\mathit{c}}^{2}$ decaying to ${\mathit{D}}^{\mathrm{*}+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$, and a ${\mathit{D}}_{\mathit{s}1}^{+}$ state of mass 2535.0\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}1.0 MeV/${\mathit{c}}^{2}$ and width 3.2 MeV/${\mathit{c}}^{2}$ at 90% confidence level, decaying to ${\mathit{D}}^{\mathrm{*}+}$${\mathit{K}}_{\mathit{s}}^{0}$ and ${\mathit{D}}^{\mathrm{*}0}$${\mathit{K}}^{+}$.

We report evidence of a narrow resonance at a mass of 2705.9 ± 3.3 ± 2.0 MeV/c2 in the final state Ω−π+ and the charge conjugate. The mass and width support the interpretation of a weakly decaying doubly strange charmed baryon, the Ωc0. Limits on the relative branching ratios for Ωc0→Ω−K−π+π+ and Ωc0→Ω−π−π+π+ are also presented.

We describe the various techniques developed in the Fermilab Wideband Experiments, E687 and FOCUS, to reconstruct long-lived states. The techniques all involve modifications to standard tracking techniques and are useful to report for future experiments.

[Formula: see text] experiment's main goal is to measure the local gravitational acceleration of antihydrogen [Formula: see text] and thus perform a direct test of the weak equivalence principle with antimatter. In the first phase of the experiment the aim is to measure [Formula: see text] with 1% relative precision. This paper presents the antihydrogen production method and a description of some components of the experiment, which are necessary for the gravity measurement. Current status of the [Formula: see text] experimental apparatus is presented and recent commissioning results with antiprotons are outlined. In conclusion we discuss the short-term goals of the [Formula: see text] collaboration that will pave the way for the first gravity measurement in the near future.

We report on the study of charm baryons decaying to Λc+: Λc★+(2625) → Λc+π+π−, Λc★+(2593) → Λc+π+π−, Σc0 → Λc+π− and Σc++ → Λc+π+. We present a confirmation of the state Λc∗+ (2593) and determine its mass difference to be M(Λc★+(2593)) − M(Λc+) = 309.2 ± 0.7 ± 0.3 MeV/c2. We determine the lower limit on the resonant branching ratio to be BR(Λc★+(2593) → Σcπ±Λc★+(2593) → Λc+π+π−) > 0.51 (90% c.l.). We also measure the mass differences M(Σc0) − M(Λc+) = 166.6±0.5±0.6 MeV/c2 and M(Σc++) − M(Λc+) = 167.6±0.6±0.6 MeV/c2. Finally, we measure the relative photoproduction cross sections for Λc★+ and Σc with respect to the (inclusive) photoproduction cross section for Λc+.

We report measurements of charm particle production asymmetries from the Fermilab photoproduction experiment E687. An asymmetry in the rate of production of charm versus anticharm particles is expected to arise primarily from fragmentation effects. We observe statistically significant asymmetries in the photoproduction of D+, D∗+ and D0 mesons and find small (but statistically weak) asymmetries in the production of the Ds+ meson and the Λc+ baryon. Our inclusive photoproduction asymmetries are compared to predictions from nonperturbative models of charm quark fragmentation.

A bakelite double gap Resistive Plate Chamber (RPC), operating in avalanche mode, has been exposed to the radiation emitted from a 252Cf source to measure its neutron and gamma sensitivity. One of the two gaps underwent the traditional electrodes surface coating with linseed oil. RPC signals were triggered by fission events detected using BaF2 scintillators. A Monte Carlo code, inside the GEANT 3.21 framework with MICAP interface, has been used to identify the gamma and neutron contributions to the total number of collected RPC signals. A neutron sensitivity of (0.63±0.02)×10−3 (average energy 2 MeV) and a gamma sensitivity of (14.0±0.5)×10−3 (average energy 1.5 MeV) have been measured in double gap mode. Measurements done in single gap mode have shown that both neutron and gamma sensitivity are independent of the oiling treatment.

A long-term aging test of a Resistive Plate Chamber (RPC) was carried out with an intense gamma 137Cs source. The detector was operated in avalanche mode and had the bakelite surface treated with linseed oil. After the irradiation the estimated dose, charge and fluence were approximately equal to the expected values after 10 years of operation in the CMS barrel region. During and after the irradiation, the RPC performance was monitored with cosmic muons and showed no relevant aging effects. Moreover, no variation of the bakelite resistance was observed.

Using data from the FOCUS (E831) experiment at Fermilab, we present new measurements for the Cabibbo-suppressed decay mode D 0 → π -π + π -π + .We measure the branching ratio0022.An amplitude analysis has been performed, a first for this channel, in order to determine the resonant substructure of this decay mode.The dominant component is the decay D 0 → a 1 (1260) + π -, accounting for 60% of the decay rate.The second most dominant contribution comes from the decay D 0 → ρ(770) 0 ρ(770) 0 , with a fraction of 25%.We also study the a 1 (1260) line shape and resonant substructure.Using the helicity formalism for the angular distribution of the decay D 0 → ρ(770) 0 ρ(770) 0 , we measure a longitudinal polarization of P L = (71 ± 4 ± 2)%.

The formation of reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50×50cm2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition and possible additional impurities have been monitored in different gamma irradiation conditions both in open and closed loop modes using a gas chromatograph. Dedicated measurements for fluoride concentration in the exhausted gas line were performed at different irradiations and operation conditions using a specific electrode and a High-Performance Liquid Chromatograph. The efficiency of the purifiers system present in the closed loop in removing the F- and others impurities has also been investigated. Finally, the chemical composition of the RPC electrode surface has been analyzed using an electron microscope equipped with an EDS/X-ray.

AEgIS (Antimatter experiment: gravity, interferometry, spectroscopy) is an experiment approved by CERN with the goal of studying antihydrogen physics. In AEgIS, antihydrogen will be produced by charge exchange reactions of cold antiprotons with positronium atoms excited in a Rydberg state (n &gt; 20). In the first phase of the experiment, controlled acceleration by an electric field gradient (Stark effect) and subsequent measurement of free fall in a Moiré deflectometer will allow a test of the weak equivalence principle. In a second phase, the antihydrogen will be slowed, confined, and laser-cooled to perform CPT studies and detailed spectroscopy. In the present work, after a general description of the experiment, the present status of advancement will be reviewed, with special attention to the production and excitation of positronium atoms.

Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report results of a search for eight rare and Standard-Model-forbidden decays: D+, Ds+ > h+/- muon-/+ muon+ (with h=pion or Kaon). Improvement over previous results by a factor of 1.7--14 is realized. Our branching ratio upper limit D+ > pion+ muon- muon+ of 8.8E-6 at the 90% C.L. is below the current MSSM R-Parity violating constraint.

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the Cabibbo-suppressed decay mode D0→K+K−π+π−. We measure: Γ(D0→K+K−π+π−)/Γ(D0→K−π−π+π+)=0.0295±0.0011±0.0008. An amplitude analysis has been performed in order to determine the resonant substructure of this decay mode. The dominant components are the decays D0→K1(1270)+K−, D0→K1(1400)+K− and D0→ρ(770)0ϕ(1020).

Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report on the measurement of the ratio of semileptonic rates \Gamma(D+ > ANTI-K pi mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.625 +/- 0.045 +/- 0.034. Allowing for the K pi S-wave interference measured previously by FOCUS, we extract the vector to pseudoscalar ratio \Gamma(D+ > ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.594 +/- 0.043 +/- 0.033 and the ratio \Gamma(D+ > ANTI-K0 mu+ nu)/\Gamma(D+ > K- pi+ pi+)= 1.019 +/- 0.076 +/- 0.065. Our results show a lower ratio for \Gamma(D > K* \ell nu})/\Gamma(D > K \ell nu) than has been reported recently and indicate the current world average branching fractions for the decays D+ >ANTI-K0(mu+, e+) nu are low. Using the PDG world average for B(D+ > K- pi+ pi+) we extract B(D+ > ANIT-K0 mu+ nu)=(9.27 +/- 0.69 +/- 0.59 +/- 0.61)%.

We present a search for a charmed pentaquark decaying strongly to D(∗)−p. Finding no evidence for such a state, we set limits on the cross-section times branching ratio relative to D∗− and D− under particular assumptions about the production mechanism.

Using a large sample of D+ -> K- pi+ mu+ nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first measurements of the helicity basis form factors free from the assumption of spectroscopic pole dominance. We also present the first information on the form factor that controls the s-wave interference discussed in a previous paper by the FOCUS collaboration. We find reasonable agreement with the usual assumption of spectroscopic pole dominance and measured form factor ratios.

We present a search for a pentaquark decaying strongly to pKS0 in γN collisions at a center-of-mass energy up to 25 GeV. Finding no evidence for such a state in the mass range of 1470MeV/c2 to 2200MeV/c2, we set limits on the yield and on the cross section times branching ratio relative to Σ∗(1385)± and K∗(892)+.

Due to its large volume (18 m3)the Resistive Plate Chamber (RPC) detector of the Compact Muon Solenoid (CMS) experiment at the LHC proton collider (CERN, Switzerland) will employ a gas re-circulation system. Since the mixture composition and quality are crucial issues for the detector operation, CMS-RPC will use an online gas analysis and monitoring system. An overview of both the CMS-RPC gas system and gas monitoring system is given and the project parameters are described.

The decay, , is dominant for a Standard Model Higgs boson in the mass range just above the exclusion limit of 114.4 GeV/c2 reported by the LEP experiments. Unfortunately, an overwhelming abundance of events arising from more mundane sources, together with the lack of precision inherent in the reconstruction of the Higgs mass, renders this decay mode a priori undetectable in the case of direct Higgs production at the LHC. It is therefore of no small interest to investigate whether can be observed in those cases where the Higgs is produced in association with other massive particles. In this note, the results of a study of Higgs bosons produced in association with top quarks and decaying via are presented. The study was performed as realistically as possible by employing a full and detailed Monte Carlo simulation of the CMS detector followed by the application of trigger and reconstruction algorithms that were developed for use with real data. Important systematic effects resulting from such sources as the uncertainties in the jet energy scale and the estimated rates for correctly tagging b jets or mistagging non-b jets have been taken into account. The impact of large theoretical uncertainties in the cross sections for plus N jets processes due to an absence of next-to-leading order calculations is also considered.

The AEgIS experiment is an international collaboration with the main goal of performing the first direct measurement of the Earth's gravitational acceleration on antimatter. Critical to the success of AEgIS is the production of cold antihydrogen (H¯) atoms. The FACT detector is used to measure the production and temperature of the H¯ atoms and for establishing the formation of a H¯ beam. The operating requirements for this detector are very challenging: it must be able to identify each of the thousand or so annihilations in the 1 ms period of pulsed H¯ production, operate at 4 K inside a 1 T solenoidal field and not produce more than 10 W of heat. The FACT detector consists of two concentric cylindrical layers of 400 scintillator fibres with a 1 mm diameter and a 0.6 mm pitch. The scintillating fibres are coupled to clear fibres which transport the scintillation light to 800 silicon photomultipliers. Each silicon photomultiplier signal is connected to a linear amplifier and a fast discriminator, the outputs of which are sampled continuously by Field Programmable Gate Arrays (FPGAs). In the course of the developments for the FACT detector we have established the performance of scintillating fibres at 4 K by means of a cosmic-ray tracker operating in a liquid helium cryostat. The FACT detector was installed in the AEgIS apparatus in December 2012 and will be used to study the H¯ formation when the low energy antiproton physics programs resume at CERN in the Summer of 2014. This paper presents the design requirements and construction methods of the FACT detector and provides the first results of the detector commissioning.

The goal of the AEIS experiment at the Antiproton Decelerator (AD) at CERN, is to measure directly the Earth's gravitational acceleration on antimatter by measuring the free fall of a pulsed, cold antihydrogen beam. The final position of the falling antihydrogen will be detected by a position sensitive detector. This detector will consist of an active silicon part, where the annihilations take place, followed by an emulsion part. Together, they allow to achieve 1% precision on the measurement of with about 600 reconstructed and time tagged annihilations.

In the path towards a muon collider with center of mass energy of 10 TeV or more, a stage at 3 TeV emerges as an appealing option. Reviewing the physics potential of such muon collider is the main purpose of this document. In order to outline the progression of the physics performances across the stages, a few sensitivity projections for higher energy are also presented. There are many opportunities for probing new physics at a 3 TeV muon collider. Some of them are in common with the extensively documented physics case of the CLIC 3 TeV energy stage, and include measuring the Higgs trilinear coupling and testing the possible composite nature of the Higgs boson and of the top quark at the 20 TeV scale. Other opportunities are unique of a 3 TeV muon collider, and stem from the fact that muons are collided rather than electrons. This is exemplified by studying the potential to explore the microscopic origin of the current $g$-2 and $B$-physics anomalies, which are both related with muons.

We present the first measurement of the lifetime of the Ωc0 baryon. The data were collected in the Fermilab high energy photoproduction experiment E687. The measured lifetime is τ = 86−20+27(stat.) ± 28(syst.) fr. Thus the Ωc0 has one of the shorter lifetimes among the weakly decaying singly charmed baryons.

Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay D0-->K+pi- with a signal yield of 149+/-31 events compared to a similarly cut sample consisting of 36 760+/-195 D0-->K-pi+ events. We use the observed ratio of D0-->K+pi- to D0-->K-pi+ (0.404+/-0.085+/-0.025)% to obtain a relationship between the D0 mixing and doubly Cabibbo suppressed decay parameters.

Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay D0→K¯0π−μ+ν. Using a model that includes a K¯0π− s-wave component, we measure the form factor ratios to be rv=1.71±0.68±0.34 and r2=0.91±0.37±0.10 and the s-wave amplitude to be A=0.35±0.22±0.05GeV−1. Finally, we measure the vector semileptonic branching ratio Γ(D0→K*(892)−μ+ν)Γ(D0→K¯0π−π+)=0.337±0.034±0.013.

The Italian National Center for Hadrontherapy (CNAO, Centro Nazionale di Adroterapia Oncologica), a synchrotron-based hospital facility, started the treatment of patients within selected clinical trials in late 2011 and 2012 with actively scanned proton and carbon ion beams, respectively. The activation of a new clinical protocol for the irradiation of uveal melanoma using the existing general-purpose proton beamline is foreseen for late 2014. Beam characteristics and patient treatment setup need to be tuned to meet the specific requirements for such a type of treatment technique. The aim of this study is to optimize the CNAO transport beamline by adding passive components and minimizing air gap to achieve the optimal conditions for ocular tumor irradiation. The CNAO setup with the active and passive components along the transport beamline, as well as a human eye-modeled detector also including a realistic target volume, were simulated using the Monte Carlo Geant4 toolkit. The strong reduction of the air gap between the nozzle and patient skin, as well as the insertion of a range shifter plus a patient-specific brass collimator at a short distance from the eye, were found to be effective tools to be implemented. In perspective, this simulation toolkit could also be used as a benchmark for future developments and testing purposes on commercial treatment planning systems.

Results on the behaviour of several bakelite Resistive Plate Chambers (RPCs) without the linseed oil treatment of the internal electrodes will be presented. Efficiency, collected charge and cluster size distributions will be compared to the ones of a standard oiled RPC. Currents and single rate are the quantities most affected by the surface treatment of the electrodes beyond the optical/mechanical properties. A factor 4 less in currents and at least a factor 10 less in single rate is achieved using standard oiled RPCs operated in streamer mode.

Fermilab high-energy photoproduction experiment E687 measures a branching ratio of Γ (DS+ → φμ+ν) /Γ (DS+ → φμ+) = 0.58 ± 0.17 (stat) ± 0.07 (sys). This branching ratio is combined with theoretical inputs to obtain a new measurement of the DS+ absolute branching ratio of Γ (DS+ → φμ+) / Γ (DS+ → all) = 0.031 ± 0.009 (stat 0.005 (sys) ± 0.004 (theoretical).

A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to measure the D0 and D+ lifetimes. Using about 210000 D0 and 110000 D+ events we obtained the following values: 409.6±1.1 (statistical)±1.5 (systematic) fs for D0 and 1039.4±4.3 (statistical)±7.0 (systematic) fs for D+.

Using a large sample of Ds to Phi mu nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of two semileptonic form factor ratios: rV and r2. We find rV = 1.549 \pm 0.250 \pm 0.145 and r2 = 0.713 \pm 0.202 \pm 0.266. These values are consistent with the rV and r2 form factors measured for the process D+ to K*bar mu nu.

We present a new measurement of the branching ratio of the Cabibbo suppressed decay D^0\to \pi^-\mu^+\nu relative to the Cabibbo favored decay D^0\to K^-\mu^+\nu and an improved measurement of the ratio |\frac{f_+^{\pi}(0)}{f_+^{K}(0)}|. Our results are 0.074 \pm 0.008 \pm 0.007 for the branching ratio and 0.85 \pm 0.04 \pm 0.04 \pm 0.01 for the form factor ratio, respectively.

The main scientific goal of the AEGIS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is the direct measurement of the Earth's gravitational acceleration g on a beam of cold antihydrogen (H¯). The production of an antihydrogen beam is achieved by a charge exchange reaction between Rydberg positronium and cold antiprotons. The H¯ beam will be accelerated up to a velocity of a few 100 m/s and the gravitational acceleration will be obtained by measuring the small vertical deflection of the beam (a few tens μm) using a Moire' deflectometer.

The goal of the AEgIS experiment is to measure the gravitational acceleration of antihydrogen – the simplest atom consisting entirely of antimatter – with the ultimate precision of 1%. We plan to verify the Weak Equivalence Principle (WEP), one of the fundamental laws of nature, with an antimatter beam. The experiment consists of a positron accumulator, an antiproton trap and a Stark accelerator in a solenoidal magnetic field to form and accelerate a pulsed beam of antihydrogen atoms towards a free-fall detector. The antihydrogen beam passes through a moiré deflectometer to measure the vertical displacement due to the gravitational force. A position and time sensitive hybrid detector registers the annihilation points of the antihydrogen atoms and their time-of-flight. The detection principle has been successfully tested with antiprotons and a miniature moiré deflectometer coupled to a nuclear emulsion detector.

Abstract The present generation of Micro-Pattern Gaseous Detectors (MPGDs) are radiation hard detectors, capable of detecting effciently particle rates of several MHz/cm 2 , while exhibiting good spatial resolution (≤ 50 µm) and modest time resolution of 5-10 ns, which satisfies the current generation of experiments (High Luminosity LHC upgrades of CMS and ATLAS) but it is not sufficient for bunch crossing identification of fast timing systems at FCC-hh. Thanks to the application of thin resistive films such as Diamond-Like Carbon (DLC) a new detector concept was conceived: Fast Timing MPGD (FTM). In the FTM the drift volume of the detector has been divided in several layers each with their own amplification structure. The use of resistive electrodes makes the entire structure transparent for electrical signals. After some first initial encouraging results, progress has been slowed down due to problems with the wet-etching of DLC-coated polyimide foils. To solve these problems a more in-depth knowledge of the internal stress of the DLC together with the DLC-polyimide adhesion is required. We will report on the production of DLC films produced in Italy with Ion Beam Sputtering and Pulsed Laser Deposition, where we are searching to improve the adhesion of the thin DLC films, combined with a very high uniformity of the resistivity values.

The CMS experiment, located at the Large Hadron Collider (LHC) in CERN, has a redundant muon system composed by three different gaseous detector technologies: Cathode Strip Chambers (in the forward regions), Drift Tubes (in the central region), and Resistive Plate Chambers (both its central and forward regions). All three are used for muon reconstruction and triggering. The CMS RPC system confers robustness and redundancy to the muon trigger. The RPC system operation in the challenging background and pileup conditions of the LHC environment is presented. The RPC system provides information to all muon track finders and thus contributing to both muon trigger and reconstruction. The summary of the detector performance results obtained with proton-proton collision at √s = 13 TeV during 2016 and 2017 data taking have been presented. The stability of the system is presented in terms of efficiency and cluster size vs time and increasing instantaneous luminosity. Data-driven predictions about the expected performance during High Luminosity LHC (HL-LHC) stage have been reported.

Abstract A new generation of resistive plate chambers, capable of withstanding high particle fluxes (up to 2000 Hz · cm -2 ) and instrumented with precise timing readout electronics is proposed to equip two of the four high pseudorapidity stations of the CMS muon system. Double-gap RPC detectors, with each gap made of two 1.4 mm High Pressure Laminate electrodes and separated by a gas gap of the same thickness, are proposed. The new layout reduces the amount of the avalanche charge produced by the passage of a charged particle through the detector. This improves the RPC rate capability by reducing the needed time to collect this charge. To keep the RPC efficiency high, a sensitive, low-noise and high time resolution front-end electronics is needed to cope with the lower charge signal of the new RPC. An ASIC called PETIROC that has all these characteristics has been selected to read out the strips of new chambers. Thin (0.6 mm) printed circuit board, 160 cm long, equipped with pickup strips of 0.75 cm average pitch, will be inserted between the two new RPC's gaps. The strips will be read out from both ends, and the arrival time difference of the two ends will be used to determine the hit position along the strip. Results from the improved RPC equipped with the new readout system and exposed to cosmic muons in the high irradiation environment at CERN GIF++ facility are presented in this work.

Studies of the decay D0 → K−μ+νμ are reported by Fermilab photoproduction experiment E687. The ratio BR(D0→ K−μ+νμ)BR(D0→ K−π+) is determined to be 0.852 ± 0.034 (statistical) ± 0.028 (systematic). Using this result and an isospin argument we infer the ratio BR(D0→ K∗−μ+νμ)BR(D0→ K−μ+νμ)= 0.62 ± 0.07 ± 0.09. The pole mass from the single pole form factor is measured to be Mpole = 1.87−0.08−0.06+0.11+0.07 GeV/c2. Using Mpole and BR(D0→ K−μ+νμ)BR(D0→ K−π+), we calculate |f + (0)| = 0.71 ± 0.03 ± 0.03. We also measure the ratio f − (0)f + (0)= −1.3−3.4+3.6± 0.6.

We report on the results of a search for fourteen flavor changing neutral current, lepton number violating, or lepton family number violating decays of the charmed meson D+ in the large charm sample recorded by the Fermilab photoproduction experiment E687. No evidence is seen for these rare and standard-model-forbidden decays, of the form D+ → h±ℓ∓ℓ+ (with h = π, K and ℓ = e, μ); we determine 90% confidence level upper limits on their absolute branching fractions in the range (9–20) × 10−5.

We report precise measurements of the D0 and D+ meson lifetimes by the E687 Collaboration at Fermilab. The measurements have been made using 16000 fully reconstructed decays of the D0 into the K−π+ and K−π+π−π+ final states and 9000 decays of the D+ into the K−π+π+ final state. The lifetimes of the D0 and D+ mesons are measured to be 0.413±0.004±0.003 ps and 1.048±0.015±01011 ps respectively.

The Resistive Plate Chambers (RPCs) sensitivity to neutrons has been simulated using GEANT code with MICAP and FLUKA interfaces. The calculations have been performed as a function of the neutrons energy in the range 0.02 eV–1 GeV. To evaluate the response of the detector in the LHC background environment, the neutron energy spectrum expected in the CMS muon barrel has been taken into account; a hit rate due to neutrons of about 0.6 Hz cm−2 has been estimated for a 250×250cm2 RPC in the RB1 station.

A precise determination of the charm-strange baryon Cascade(c)+ lifetime is presented. The data were accumulated by the Fermilab high-energy photoproduction experiment FOCUS. The measurement is made with 300 Cascade(c)+ --> Cascade- pi+ pi+ decays, 130 Cascade(c)+ --> Sigma+ K- pi+ decays, 45 Cascade(c)+ --> p K- pi+ decays and 58 Cascade(c)+ --> Lambda K- pi+ pi+ decays. The Cascade(c)+ lifetime is measured to be 0.439+/-0.022+/-0.009 ps.

A method to simulate the Resistive Plate Chambers (RPCs) γ sensitivity has been developed using a Monte Carlo code. The sensitivity has been evaluated as a function of the γ energy in the range 0.1–100 MeV and for different spectra. To evaluate the response of the detector in a Large Hadron Collider (LHC) background environment the γ energy spectrum expected in the CMS muon barrel has been taken into account and the RPC γ sensitivity evaluated as a function of the detector size.

We present the first clear observation of the doubly Cabibbo suppressed decay D+→K−K+K+ and the first observation of the singly Cabibbo suppressed decay Ds+→K−K+K+. These signals have been obtained by analyzing the high statistics sample of photoproduced charm particles of the FOCUS (E831) experiment at Fermilab. We measure the following relative branching ratios: Γ(D+→K−K+K+)/Γ(D+→K−π+π+)=(9.49±2.17±0.22)×10−4 and Γ(Ds+→K−K+K+)/Γ(Ds+→K−K+π+)=(8.95±2.12+2.24−2.31)×10−3, where the first error is statistical and the second is systematic.

Using the FOCUS spectrometer with photon beam energies between 20 and 160 \gev, we confirm the existence of a diffractively photoproduced enhancement in $K^+K^-$ at 1750 \mevcc with nearly 100 times the statistics of previous experiments. Assuming this enhancement to be a single resonance with a Breit-Wigner mass shape, we determine its mass to be $1753.5\pm 1.5\pm 2.3$ \mevcc and its width to be $122.2\pm 6.2\pm 8.0$ \mevcc. We find no corresponding enhancement at 1750 \mevcc in $K^*K$, and again neglecting any possible interference effects we place limits on the ratio $\Gamma (X(1750) \to K^*K)/\Gamma (X(1750) \to K^+K^-)$. Our results are consistent with previous photoproduction experiments, but, because of the much greater statistics, challenge the common interpretation of this enhancement as the $\phi (1680)$ seen in $e^+e^-$ annihilation experiments.

A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+) decays represents a significant improvement over the present world average.

Received 13 February 2002DOI:https://doi.org/10.1103/PhysRevLett.88.159903©2002 American Physical Society

Using data collected by the high energy photoproduction experiment FOCUS at Fermilab we study the doubly and singly Cabibbo suppressed decays D+ and Ds+ --> K+ pi+ pi-. Branching ratios and Dalitz plot analyses are performed.

The CMS detector at the LHC has a redundant muon system.Two independent muon systems are used in the L1 trigger.One of them is based on wire chambers, the other on RPC detectors.Properly combining the answers of the two systems results in a highly efficient L1 trigger with high flexibility from the point of view of rate control.Simulation results show, however, that the RPC system suffers from false triggers caused by coincidence of spurious hits.System improvements, which could avoid oiling the chambers, are possible.RPCs have also proved to be very useful for muon track reconstruction.

Using data collected by the fixed target Fermilab experiment FOCUS, we measure the branching ratios of the Cabibbo-favored decays Ξc+→Σ+K−π+, Ξc+→Σ+K̄∗(892)0, and Ξc+→Λ0K−π+π+ relative to Ξc+→Ξ−π+π+ to be 0.91±0.11±0.04, 0.78±0.16±0.06, and 0.28±0.06±0.06, respectively. We report the first observation of the Cabibbo-suppressed decay Ξc+→Σ+K+K− and we measure the branching ratio relative to Ξc+→Σ+K−π+ to be 0.16±0.06±0.01. We also set 90% confidence level upper limits for Ξc+→Σ+φ and Ξc+→Ξ∗(1690)0(Σ+K−)K+ relative to Ξc+→Σ+K−π+ to be 0.12 and 0.05, respectively. We find an indication of the decays Ξc+→Ω−K+π+ and Ξc+→Σ∗(1385)+K̄0 and set 90% confidence level upper limits for the branching ratios with respect to Ξc+→Ξ−π+π+ to be 0.12 and 1.72, respectively. Finally, we determine the 90% C.L. upper limit for the resonant contribution Ξc+→Ξ∗(1530)0π+ relative to Ξc+→Ξ−π+π+ to be 0.10.

We apply a genetic programming technique to search for the doubly Cabibbo suppressed decays Λc+→pK+π− and Ds+→K+K+π−. We normalize these decays to their Cabibbo favored partners and find BR(Λc+→pK+π−)/BR(Λc+→pK−π+)=(0.05±0.26±0.02)% and BR(Ds+→K+K+π−)/BR(Ds+→K−K+π+)=(0.52±0.17±0.11)% where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find <0.46 and <0.78%, respectively. This is the first successful use of genetic programming in a high energy physics data analysis.

We present here a new application of silicon sensors aimed at the direct detection of antinucleons annihilations taking place inside the sensor's volume.Such detectors are interesting particularly for the measurement of antimatter properties and will be used as part of the gravity measurement module in the AEgIS experiment at the CERN Antiproton Decelerator.One of the goals of the AEgIS experiment is to measure the gravitational acceleration of antihydrogen with 1% precision.Three different silicon sensor

During 2013 and 2014 (Long Shutdown LS1) the CMS experiment is upgrading the forward region installing a fourth layer of RPC detectors in order to complete and improve the muon system performances in the view of the foreseen high luminosity run of LHC. The new two endcap disks consists of 144 double-gap RPC chambers assembled at three different production sites: CERN, Ghent (Belgium) and BARC (India). The chamber components as well as the final detectors are subjected to full series of tests established in parallel at all the production sites.

The Resistive Plate Chambers (RPCs) are employed in the CMS Experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This article presents results of the radiation background measurements performed with the 2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given to the measurements of the background distribution inside the RPCs. The expected background rates during the future running of the LHC are estimated both from extrapolated measurements and from simulation.

A precise measurement of the ${\mathit{D}}_{\mathit{s}}^{\ifmmode\pm\else\textpm\fi{}}$ meson lifetime is reported. The data were accumulated by the high energy photoproduction experiment E687 at Fermilab in the 1990--1991 fixed target run. The measurement has been done using 900 fully reconstructed ${\mathit{D}}_{\mathit{s}}^{\ifmmode\pm\else\textpm\fi{}}$\ensuremath{\rightarrow}\ensuremath{\varphi}${\mathrm{\ensuremath{\pi}}}^{\ifmmode\pm\else\textpm\fi{}}$ decays. The lifetime of the ${\mathit{D}}_{\mathit{s}}^{\ifmmode\pm\else\textpm\fi{}}$ meson is measured to be 0.475\ifmmode\pm\else\textpm\fi{}0.020\ifmmode\pm\else\textpm\fi{}0.007 ps.

Measurements of the mass and lifetime of the ${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{+}$ decaying into ${\mathrm{\ensuremath{\Xi}}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{+}$ are presented. The data were accumulated by the Fermilab high-energy photoproduction experiment E687. The mass of the ${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{+}$ is measured to be 2464.4\ifmmode\pm\else\textpm\fi{}2.0\ifmmode\pm\else\textpm\fi{}1.4 MeV/${\mathit{c}}^{2}$ and the lifetime is measured to be 0.${41}_{\mathrm{\ensuremath{-}}0.08}^{+0.11}$\ifmmode\pm\else\textpm\fi{}0.02 ps.

The fermilab high-energy photoproduction experiment E687 provides a sample of approximately 90 events of the decay mode D+s→ φμ+ ν. The ratios of the form factors governing the decay are measured to be Rv=1.8±0.9±0.2 and R2= 1.1±0.8±0.1, implying a polarization of Г1/Гt = 1.0±0.5±0.1 for the electron decay, consistent with our measurement of the form factor for the decay D+ → K∗0 μ+ ν.

A measurement of the lifetime of the charmed strange baryon ${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{0}$ is presented. The data were accumulated by the Fermilab high energy photoproduction experiment E687. The measurement has been made using 42\ifmmode\pm\else\textpm\fi{}10 ${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Xi}}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{+}$ decays. The lifetime of the ${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{0}$ is measured to be 0.${101}_{\mathrm{\ensuremath{-}}0.017}^{+0.025}$\ifmmode\pm\else\textpm\fi{}0.005 ps and its mass is measured to be 2462.1\ifmmode\pm\else\textpm\fi{}3.1\ifmmode\pm\else\textpm\fi{}1.4 MeV/${\mathit{c}}^{2}$.