V. Hagopian

The Regge-pole elementary particle theory predicts the existence of a spin-2 particle having the quantum numbers of the vacuum and with a mass of the order of 1.0 to 1.4 Bev. The particle could decay into two pi mesons and should be observed as a pi - pi resonance with isotopic spin T = 0. Experimental evidence is presented for the existence of such a particle. Using a 3 Bev/c separated pi - beam and the BNL 20-inch hydrogen bubble chamber, the reactions pi /sup -/ + p yields pi /sup -/ + pi /sup 0/ + p and pi /sup -/ + p yields pi /sup -/ + pi /sup +/ + n were studied. Plots of the data obtained irom these reactions are presented and analyzed. It is concluded that there is evidence for a T = 0 particle or resonance, the f/sup 0/, at an energy of 1250 plus or minus 25 Mev, with a width of 100 plus or minus 50 Mev. The spin was not determined, but is thought to be either 0 or 2. (H.D.R.)

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region ( $3\leq|\eta|\leq5$ ), and is essential for a large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels in Higgs production. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h≈5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as $\frac{a}{\sqrt{E}}\oplus{b}$ . The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%.

The cross sections for ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ elastic scattering, and the $I=0$ $s$-wave and $I=1$ $p$-wave phase shifts, ${{\ensuremath{\delta}}_{0}}^{0}$ and ${\ensuremath{\delta}}_{1}$, are calculated for $400<{M}_{\ensuremath{\pi}\ensuremath{\pi}}<900$ MeV using a Chew-Low extrapolation. The extrapolation information permits resolving a fourfold ambiguity which has been present in other attempts to determine ${{\ensuremath{\delta}}_{0}}^{0}$ from the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}n$. The result for ${{\ensuremath{\delta}}_{0}}^{0}$ is consistent with a curve which increases through 90\ifmmode^\circ\else\textdegree\fi{} around ${M}_{\ensuremath{\pi}\ensuremath{\pi}}=720$. The $\ensuremath{\rho}$ width obtained from the extrapolated $p$-wave amplitude is 105 \ifmmode\pm\else\textpm\fi{} 15 MeV.

A study of 13.3\ifmmode\times\else\texttimes\fi{}${10}^{6}$ stopped ${K}^{+}$ in a heavy-liquid bubble chamber yielded 269 ${K}_{e4}$ decays of the type ${e}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\nu}$, a total greater by a factor of 4 than the number found in a previous experiment. No examples of ${e}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}\overline{\ensuremath{\nu}}$ were found. With 95% confidence, the upper limit for the decay rate of ${K}_{e4}({e}^{\ensuremath{-}})$ was found to be 56 ${\mathrm{sec}}^{\ensuremath{-}1}$. The rate for ${K}_{e4}({e}^{+})$ was found to be (2.60\ifmmode\pm\else\textpm\fi{}0.30)\ifmmode\times\else\texttimes\fi{}${10}^{3}$ ${\mathrm{sec}}^{\ensuremath{-}1}$. The angular distributions and the dipion invariant-mass plot have been fitted by varying the form factors ${f}_{s}$, ${f}_{p}$, $g$, and $h$, and the difference between $s$- and $p$-wave $\ensuremath{\pi}\ensuremath{-}\ensuremath{\pi}$ phase shift. Two acceptable solutions have been found. Both agree that the vector form factor $h$ is significantly nonzero and that its sign is negative with respect to that of ${f}_{g}$. Also, it has been found necessary to include ${f}_{p}$ in order to obtain a good fit. Although both solutions give the magnitude of the phase difference to be 25\ifmmode\pm\else\textpm\fi{}9 deg, the two estimates have opposite sign. No evidence of a $\ensuremath{\sigma}$ resonance is seen. The angular distributions are found to be consistent with time-reversal invariance, and with the locality of lepton production.

We have performed a high-statistics experiment on the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{+}{\overline{K}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}n$ at 8.0 GeV/c. A Dalitz-plot analysis of the ${K}^{+}{\overline{K}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ system finds that the $D(1285)$ is a ${J}^{\mathrm{PG}}={1}^{++}$ state coupling predominantly to a $\ensuremath{\delta}\ensuremath{\pi}$ decay channel, while the $E(1420)$ peak consists mostly of a ${J}^{\mathrm{PG}}={0}^{\ensuremath{-}+}$ wave with a substantial $\ensuremath{\delta}\ensuremath{\pi}$ decay mode. There is little evidence of a ${1}^{++}$ resonance at the $E$ mass.

Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. The energy dependent time slewing effect was measured and tuned for optimal performance.

Data from two ${\ensuremath{\pi}}^{\ensuremath{-}}$+proton experiments, at 2.75 and 3.0 GeV/c, have been compared and combined. Some 3400 events of the final-state ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ neutron and 2000 of ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ proton were found. These events are dominated by the $\ensuremath{\rho}$ resonance. The decay angular distribution of the ${\ensuremath{\rho}}^{\ensuremath{-}}$ agrees surprisingly well with the one-pion-exchange theory modified for absorption effects, as calculated by Gottfried and Jackson. The $\ensuremath{\rho}$-production angular distributions exhibit a difference between ${\ensuremath{\rho}}^{\ensuremath{-}}$ and ${\ensuremath{\rho}}^{0}$ at ${\ensuremath{\Delta}}^{2}$ values (4-momentum transfer to nucleon, squared) of 20 to 40 ${{M}_{\ensuremath{\pi}}}^{2}\ifmmode\cdot\else\textperiodcentered\fi{}{\ensuremath{\rho}}^{0}$ production shows a weak backward peak. The ${\ensuremath{\rho}}^{0}$ mass region shows effects interpretable as due to the 720-MeV $T=0$ $s$-wave $\ensuremath{\pi}\ensuremath{\pi}$ resonance, and to ${\ensuremath{\omega}}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay. Analysis of the data in terms of $\ensuremath{\pi}\ensuremath{\pi}$ scattering is discussed. A simple phase-shift analysis using "physical-region" single-pion-production data directly, without extrapolation to the one-pion pole, will not in general be valid for ${\ensuremath{\Delta}}^{2}$ greater than 2 or 3 ${{M}_{\ensuremath{\pi}}}^{2}$; insufficient information exists to determine whether data of lower ${\ensuremath{\Delta}}^{2}$ values can be meaningfully used without extrapolation. $S$-wave $\ensuremath{\pi}\ensuremath{\pi}$ scattering in the mass region below the $\ensuremath{\rho}$ is discussed. The ABC and $\ensuremath{\sigma}$ effects do not show up in these data.

We have performed a partial-wave analysis of the ${K}^{+}{K}_{S}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ system produced in the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{+}{\overline{K}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}n$ at 8 GeV/c. We present the results of the analysis of 30740 events in the mass range 1.24-1.60 GeV/${\mathit{c}}^{2}$, with $0.0\ensuremath{\le}\ensuremath{-}t\ensuremath{\le}1.0$ ${\mathrm{GeV}}^{2}$/${\mathit{c}}^{2}$. In the 1.28-GeV/${\mathit{c}}^{2}$ mass region, we see evidence for a ${J}^{\mathrm{PG}}={0}^{\ensuremath{-}+}$ resonance in addition to the resonant ${1}^{++}$ wave. We observe a ${0}^{\ensuremath{-}+}$ resonance and possibly a small ${1}^{++}$ resonance in the 1.42-GeV/${\mathit{c}}^{2}$ region. We also observe a ${1}^{++}$ state near 1.5 GeV/${\mathit{c}}^{2}$.

Evidence for a bound ${\ensuremath{\Delta}}_{33}(1236)\ensuremath{-}{\ensuremath{\Delta}}_{33}(1236)$ component of the deuteron is sought by using ${\ensuremath{\pi}}^{+}$, ${\ensuremath{\pi}}^{\ensuremath{-}}$, and ${K}^{+}$ mesons as probes of nuclear structure. Events are observed which might contain $\ensuremath{\Delta}(1236)$ "spectators" in the breakup of a deuteron in a $\ensuremath{\Delta}\ensuremath{\Delta}$ state. However, other mechanisms may contribute to the signal, and we cannot unambiguously ascribe our events to a $\ensuremath{\Delta}\ensuremath{\Delta}$ contribution in the deuteron. With certain assumptions we obtain an upper limit of \ensuremath{\sim}0.7% for the $\ensuremath{\Delta}\ensuremath{\Delta}$ component of the deuteron.

Sixty-two charm events have been observed in an exposure of the SLAC Hybrid Facility toa backward sacttered laser beam. Based on 22 neutral and 21 charged decays we have measured the charmed-meson lifetimes to be τD0=(6.8+2.3−1.8)×10−13 sec, τD±=(7.4+2.3−2.0)×10−13 sec and their ratio τD±τD0=1.1+0.6−0.3. The inclusive charm cross section at a photon energy of 20 GeV has been measured to be 56+24−23 nb. Evidence is presented for a non-D¯D component to charm production, consistent with (35±20)% Λ+c production and some D*± production. We have found no unambiguous F decays.Received 27 December 1983DOI:https://doi.org/10.1103/PhysRevD.30.1©1984 American Physical Society

A bubble-chamber experiment in which the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}\ensuremath{\pi}+\ensuremath{\pi}+N$ was studied at a beam momentum of 2.14 BeV/c yielded 1533 and 2234 events of the final states ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}p$ and ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}n$, respectively. These events are dominated by the formation of the $\ensuremath{\rho}$ resonance, which is produced mostly in the forward direction. Both the production and decay angular distributions of the ${\ensuremath{\rho}}^{\ensuremath{-}}$ agree very well with the predictions of the one-pion exchange theory modified by absorption effects. The decay angular distribution of the ${\ensuremath{\rho}}^{0}$ shows the well-known forward-backward asymmetry. This effect is interpretable as the result of the interference between the ${\ensuremath{\rho}}^{0}$ and an isospin-zero $s$-wave $\ensuremath{\pi}\ensuremath{-}\ensuremath{\pi}$ resonance. The production of the ${\ensuremath{\rho}}^{0}$, in addition to its forward peak, shows a weak backward peak. Partial cross sections of various final states are also presented.

A new experiment for determining the upper limit for the branching ratio $R$ of the process ${\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}+\ensuremath{\gamma}$ relative to the normal decay mode ${\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}+\ensuremath{\nu}+\overline{\ensuremath{\nu}}$ yields a value of $R$ of less than 1.2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$ with a 90% confidence level.

Many samples of different plastic scintillators and scintillating fibers were irradiated with the Florida State University 2.5 MeV electron beam. The advantages of irradiating with an electron beam as compared to the standard gamma source were demonstrated: wide dynamic range of dose rates, possibility of irradiating long (and/or wide) samples, such as scintillating fibers, or simultaneous irradiation of many small samples in a short time. Study of effects of variation in sample composition and storage temperature during the recovery stage on the final level of radiation damage was performed. Finally, several samples of scintillating fibers were tested for radiation resistance. The 3-hydroxyflavone-doped fibers were found to recover best and show only small permanent damage after a 10 Mrad radiation dose.

In a sample of 8300 events of the type ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}+{\ensuremath{\pi}}^{+}+n$ obtained from a hydrogen bubble chamber exposure, a strong sharp $\ensuremath{\omega}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}+{\ensuremath{\pi}}^{+}$ peak is observed. Analysis indicates that this $\ensuremath{\omega}\ensuremath{\rightarrow}2\ensuremath{\pi}$ decay interferes almost perfectly constructively with the prominent decay of ${\ensuremath{\rho}}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}+{\ensuremath{\pi}}^{+}$. The interference phase is determined to be -15\ifmmode^\circ\else\textdegree\fi{}\ifmmode\pm\else\textpm\fi{}30\ifmmode^\circ\else\textdegree\fi{}. This phase is consistent with predictions of $\ensuremath{\pi}\ensuremath{-}B$ degeneracy using Regge-pole methods.

Eleven neutral and nine charged decays of charmed particles have been observed in a sample of 205 000 hadronic interactions in a 1.2-million-picture exposure of the SLAC Hybrid Facility bubble chamber to a 20-GeV/c backward-scattered laser beam. The charged and neutral lifetimes were determined to be ${8.2}_{\ensuremath{-}2.5}^{+4.5}$\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ and ${6.7}_{\ensuremath{-}2.0}^{+3.5}$\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ sec, respectively, with a ratio of ${1.2}_{\ensuremath{-}0.5}^{0.9}$.

Abstract The two Zero Degree Calorimeters (ZDCs) of the CMS experiment are located at ± 140 m from the collision point and detect neutral particles in the |η| > 8.3 pseudorapidity region. This paper presents a study on the performance of the ZDC in the 2016 pPb run. The response of the detectors to ultrarelativistic neutrons is studied using in-depth Monte Carlo simulations. A method of signal extraction based on template fits is presented, along with a dedicated calibration procedure. A deconvolution technique for the correction of overlapping collision events is discussed.

We report on the response of a prototype CMS hadron calorimeter module to charged particle beams of pions, muons, and electrons with momenta up to 375GeV/c. The data were taken at the H2 and H4 beamlines at CERN in 1995 and 1996. The prototype sampling calorimeter used copper absorber plates and scintillator tiles with wavelength shifting fibers for readout. The effects of a magnetic field of up to 3 T on the response of the calorimeter to muons, electrons, and pions are presented, and the effects of an upstream lead tungstate crystal electromagnetic calorimeter on the linearity and energy resolution of the combined calorimetric system to hadrons are evaluated. The results are compared with Monte Carlo simulations and are used to optimize the choice of total absorber depth, sampling frequency, and longitudinal readout segmentation.

A large lead glass shower detector containing 204 lead glass blocks and 250 finger hodoscope elements has been constructed and operated in a photoproduction experiment at the SLAC Hybrid facility. An energy resolution of σE/E = (0.84+4.8/E12)% has been achieved for electron energies between 4 and 16 GeV. Details of the apparatus, its stability monitoring system, and its use in triggering the bubble chamber are presented. The performance of the detector in electron identification and π0 reconstruction is discussed.

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS.

In a sample of 8300 events of the type ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}n$ and 6800 events of the type ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}p$ obtained with 2.3-BeV/c incident ${\ensuremath{\pi}}^{\ensuremath{-}}$, substantial backward ${\ensuremath{\rho}}^{0}$ production is seen. The decay angular distribution of these backward ${\ensuremath{\rho}}^{0}$ events was found to be anisotropic. The $u$ distribution for the backward ${\ensuremath{\rho}}^{0}'\mathrm{s}$ is compared with the theoretical predictions of the strong-cut Reggeized absorption model. A small amount of backward ${\ensuremath{\rho}}^{\ensuremath{-}}$ production is also seen.

The Princeton-Pennsylvania accelerator 15-in. hydrogen bubble chamber was used to investigate ${\ensuremath{\pi}}^{+}p$ associated production at 1.7 $\frac{\mathrm{GeV}}{c}$. Approximately 4000 events were found; about half of these were in the ${\ensuremath{\Sigma}}^{+}{K}^{+}$ channel. The $\ensuremath{\Lambda}{K}^{+}{\ensuremath{\pi}}^{+}$ channel dominates the remaining half of the data. We find evidence for the existence of a $T=1$ hyperon resonance at 1475\ifmmode\pm\else\textpm\fi{}15 MeV with a width of 30\ifmmode\pm\else\textpm\fi{}15 MeV in the $\ensuremath{\Lambda}{K}^{+}{\ensuremath{\pi}}^{+}$, ${\ensuremath{\Sigma}}^{+}{K}^{+}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\Sigma}}^{0}{K}^{+}{\ensuremath{\pi}}^{+}$, and $P{K}^{+}{\overline{K}}^{0}$ channels. The cross sections of the strange-particle channels and the branching ratios of various resonances are also presented.

A Dalitz-plot analysis of 620 E(1420) events was performed on the reaction p\ifmmode\bar\else\textasciimacron\fi{}p\ensuremath{\rightarrow}(${K}_{S}^{0}$${K}^{+}$${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$)X at 6.6 GeV/c, obtained at the Brookhaven National Laboratory Multiparticle Spectrometer facility. The mass and width of the E(1420) peak are 1424\ifmmode\pm\else\textpm\fi{}3 and 60\ifmmode\pm\else\textpm\fi{}10 MeV, respectively. The best fit to the E(1420) is a ${J}^{\mathrm{PG}}$${=0}^{\mathrm{\ensuremath{-}}+}$ state with a substantial \ensuremath{\delta}\ensuremath{\pi} decay mode, produced over a large nonresonant background of ${1}^{++}$ ${K}^{\mathrm{*}}$K and phase space. This fit shows the same characteristics as the E(1420) observed in our companion ${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$p experiment.

Abstract Plastic scintillators and wavelength shifting fibers have been placed in magnetic fields of up to 20 T and the change in light yield measured. The light yield in scintillators increases at very low magnetic fields and continues to increase with increasing field until saturation at about 2 T. The maximum increase is between 6% and 8%, depending on the plastic composition. This increase is due to the polymer and not due to the dyes (fluors) used in the scintillators. No change of light yield due to magnetic fields has been observed in wavelength shifting fibers.

Data from a 15-GeV/c ${\ensuremath{\pi}}^{+}d$ experiment have been used to search for both short- and long-lived narrow resonances. No statistically significant high-mass narrow resonance has been observed up to a mass of 5 GeV. There is a single long-lived $V$ that remains unexplained. Cross-section limits (95% confidence level) of 0.7 \ensuremath{\mu}b for the long-lived possibility and 2 to 4 \ensuremath{\mu}b for the short-lived possibilities have been obtained.

Forty-seven charm events have been observed in an exposure of the SLAC Hybrid Facility bubble chamber to a 20-GeV backward-scattered laser beam. Thirty-seven events survive all the necessary cuts imposed. Based on this number the total charm cross section is calculated to be ${63}_{\ensuremath{-}28}^{+33}$ nb.

Abstract We present a measurement of the polarization and decay asymmetry parameters of the Ξ − inclusively produced in the forward direction in K − p interactions at 5 GeV/ c . The Ξ − decay parameters have been determined to be α Ξ = −0.405 ± 0.029 and Φ Ξ = 14.7° ± 16.0° from a sample of 20 865 events. A linear rise of the Ξ − polarization has been seen with respect to the transverse momentum of the Ξ − , reaching a maximum of 49 ± 4% at P ⊥ ∼ 0.50 GeV/ c . The value of α Ξ is consistent with the world average prior to 1975, but below the value measured by two recent experiments.

A search for narrow $\overline{p}p$ states (width \ensuremath{\lesssim} 20 MeV/${\mathit{c}}^{2}$) has been conducted in the Brookhaven National Laboratory multiparticle spectrometer. No significant structure has been observed in events where the $\overline{p}p$ system has been produced forward in the laboratory. Upper limit cross sections (95% confidence level) for $\overline{p}p$ masses below 2.2 ${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c}}^{2}$ are \ensuremath{\le}0.12 \ensuremath{\mu}b and \ensuremath{\le}0.22 \ensuremath{\mu}b for the final states $\overline{p}p{\ensuremath{\pi}}^{0}$ and $\overline{p}p{\ensuremath{\rho}}^{0}$, respectively.

3114 events of the reaction ${\ensuremath{\pi}}^{+}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}p{p}_{s}$, where ${p}_{s}$ is a nonparticipating spectator, were studied in the SLAC 82-inch bubble chamber. A longitudinal-phase-space (LPS) analysis was performed to separate the various $t$-channel exchange mechanisms, e.g., $\ensuremath{\pi}$ or Pomeron exchange. The validity of the LPS method was tested for pion exchange by generating events using the one-pion-exchange model modified by absorption (OPEA). The model and the data agreed extremely well. The principal features of the data include the ${\ensuremath{\rho}}^{0}$, ${f}^{0}$, ${\ensuremath{\Delta}}^{0}$, and ${N}^{*}'\mathrm{s}$. The LPS analysis also reveals the ${g}^{0}$, but a slight modification of the standard LPS selection criteria enhances the ${g}^{0}$, as expected by OPEA-model calculations.

About 1800 events of the reaction ${\ensuremath{\pi}}^{+}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}d$ have been obtained from 387 000 photographs of the SLAC 82-in. bubble chamber corresponding to a 495 \ifmmode\pm\else\textpm\fi{} 25 \ensuremath{\mu}b cross section. The increasing cross section of this reaction with beam momentum is explained in terms of minimum momentum-transfer cutoff. The ${D}^{*}(2200)$ is observed as both $d{\ensuremath{\pi}}^{+}$ and $d{\ensuremath{\pi}}^{\ensuremath{-}}$ mass peaks. The ${A}_{1}({\ensuremath{\rho}}^{0}{\ensuremath{\pi}}^{+})$ is consistent with a Deck-type mechanism. The ${A}_{3}({f}^{0}{\ensuremath{\pi}}^{+})$ is also observed, but the ${A}_{4}$ peak recently claimed is not seen in these data. There is no statistically significant $3\ensuremath{\pi}$ mass enhancement at the ${A}_{2}$ region, but indirect evidence indicates some ${A}_{2}$ production.

The energy resolution, linearity and e/π response of model SDC calorimeter configurations were measured. They consisted of a fine sampling lead electromagnetic (e.m.) compartment and either a lead or iron hadronic (HAD) compartment. The data indicate that the lead-scintillator and iron-scintillator hadronic calorimeters have comparable resolutions and linearity after a relative weighting of signals from the EM and HAD compartments is made.

${{\ensuremath{\Xi}}^{*}}^{\ensuremath{-}}$ production was studied in the reaction ${K}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{{K}^{+}}_{\mathrm{slow}}+{X}^{\ensuremath{-}}$ at 5 GeV/c. The slow ${K}^{+}$ was electronically detected, while the ${X}^{\ensuremath{-}}$ was observed as a missing mass, thus allowing for observation of all ${\ensuremath{\Xi}}^{*}$ independent of decay mode. The observed $\ensuremath{\Xi}$ states were $\ensuremath{\Xi}(1320)$, $\ensuremath{\Xi}(1530)$, $\ensuremath{\Xi}(1820)$, $\ensuremath{\Xi}(2030)$, $\ensuremath{\Xi}(2250)$, $\ensuremath{\Xi}(2370)$, and $\ensuremath{\Xi}(2500)$. These data establish and confirm the existence of $\ensuremath{\Xi}(2250)$ and indicate a peculiar production-cross-section behavior for the ${\ensuremath{\Xi}}^{*}(2370)$.

The SLAC 40-inch bubble chamber augmented by an array of lead-glass detectors was used to study the reaction ${\ensuremath{\pi}}^{+}$p\ensuremath{\rightarrow}${\ensuremath{\Delta}}^{++}$${\ensuremath{\pi}}^{0}$${\ensuremath{\pi}}^{0}$ at 15.7 GeV/c. No new high-mass neutral mesons are seen at a sensitivity of 14.2 events/\ensuremath{\mu}b. A moments and amplitude analysis indicates that only S and D waves contribute to the ${\ensuremath{\pi}}^{+}$${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\ensuremath{\pi}}^{0}$${\ensuremath{\pi}}^{0}$ cross section. A one-pion-exchange-model calculation is performed using phase-shift measurements from other experiments. The older phase shifts from Estabrooks and Martin are in better agreement with our data than are the more recent ones of Biswas et al.

The reaction ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}+p$ has been studied in the 15-in. bubble chamber at the Princeton-Pennsylvania Accelerator. The elastic scattering cross section was determined to be 8.5 \ifmmode\pm\else\textpm\fi{} 0.2 mb. The forward peak fits to an exponential in $t$ with a slope of 8.1 \ifmmode\pm\else\textpm\fi{} 0.2 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{\ensuremath{-}2}$. The forward differential cross section $\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}}(0)=17.9\ifmmode\pm\else\textpm\fi{}0.7$ mb/sr. A fit of the center-of-mass angular distribution to Legendre polynomials needed terms up to the 12th order, corresponding to the highest nonzero partial wave of $L=6$.

A study of the possibility of using an absorption model to obtain a unique $s$-wave $I=0$ $\ensuremath{\pi}\ensuremath{\pi}$ phase shift from the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}n$ was made. Applying the model to combined data from several latoratories, we obtained a set of reasonable (but twofold ambiguous) values for the isospin-zero $s$-wave phase shift ${{\ensuremath{\delta}}_{0}}^{0}$, using the isotropic moment of the dipion decay distribution. Values for ${{\ensuremath{\delta}}_{0}}^{0}$ deduced by using the $s\ensuremath{-}p$ wave interference term in the dipion decay cross section agreed well with previous (twofold ambiguous) results obtained by extrapolation procedures. Comparing the two sets of twofold ambiguous solutions for ${{\ensuremath{\delta}}_{0}}^{0}$, the lower or "down" branch was preferred marginally in the dipion mass region below the $\ensuremath{\rho}$ meson. No unique conclusion could be drawn in the higher-mass region. We emphasize the model dependence of these results, but we believe that similar studies with improved statistics for $\ensuremath{-}t>{\ensuremath{\mu}}^{2}$ would yield similar results. Good data for $\ensuremath{-}t<{\ensuremath{\mu}}^{2}$ are required to do definitive model-independent analyses.

The SDC collaboration for one of the SSC experiments has decided to use the tile-fiber system as the active medium of the calorimeter. Using commercially available scintillating plates and wave shifting fibers, the light output and radiation damage have been measured. The uniformity is within 5%, except near the edges for tiles of sizes 10 cm × 10 cm and 25 cm × 25 cm. The tested tile-fiber systems with radiation damage of up to 10 megarads retain their uniformity. The loss of light is about 15% for one megarad. Most scintillators and fibers are similar to each other, with variation in radiation damage of 10% to 20%. Light output increases approximately linearly with the diameter of the fiber. Radiation damage is less for tiles with multiple fibers.

Quartz fibers are used in high energy physics experiments as the active medium in high radiation area calorimetry. Quarts fibers are also used in the transmission of optical signals. Even though quartz does not damage by moderate amounts of irradiation, the clad of the fibers and the protective coating (buffer) do damage reducing light transmission. Various types of quartz fibers have been irradiated and measured for light transmission. The most radiation hard quartz fibers are those with quartz clad and aluminium buffer.

The average fraction, , of jet momentum carried by the associated charged leading hadron has been determined in the reactionp+N→h 1+h 2+X whereN is the target nucleon;h 1,h 2 are the leading particles of two jets produced at highP ⊥. An 800 GeV/c proton beam and 4 nuclear targets: Be, Al, Fe and W were used. The distributions agree with the QCD-parton model predictions for single independent protonnucleon scattering and independent fragmentation process.

Fermilab experiment 711 has investigated proton-nucleus collisions in which two high-transverse-momentum hadrons are produced forming high-mass ++, +-, and -- charged states, using an 800-GeV/c proton beam on targets of beryllium, aluminum, iron, and tungsten. Our data cover the range in dihadron mass from 6 to 15 GeV/${\mathit{c}}^{2}$. We show here that the dependence of the cross section on atomic weight A can be parametrized as ${\mathit{A}}^{\mathrm{\ensuremath{\alpha}}}$ where \ensuremath{\alpha}=1.043\ifmmode\pm\else\textpm\fi{}0.011(stat)\ifmmode\pm\else\textpm\fi{}0.025 (syst), and is independent of the charge state of the dihadron system.

Experimental data have shown that the light output of a scintillator depends on the magnitude of the externally applied magnetic fields, and that this variation can affect the calorimeter calibration and possibly resolution. The goal of the measurements presented here is to study the light yield of scintillators in high magnetic fields in conditions that are similar to those anticipated for the LHC CMS detector. Two independent measurements were performed, the first at Fermilab and the second at the National High Magnetic Field Laboratory at Florida State University.

The CMS detector at the CERN Large Hadron Collider is being built to study particle physics at the energy frontier. An important detector subsystem of CMS is the hadron calorimeter (HCAL), used for the measurement of particle and jet energies and to identify and measure missing transverse energy in collision events. This paper provides details of the electro-optical interfaces for the barrel and endcap regions of the HCAL called readout boxes (RBX). These system elements are located "on detector" and operate in regions of very high magnetic field, converting scintillation signals for megatile sampling layers to tower geometry for energy measurement.

The Hadron Calorimeter of CMS is about 1,000 tons of copper and scintillator sandwich in a 4 tesla magnetic field. It will be built in three segments, the barrel surrounding the central portion and the two end caps. The scintillators will use a tower structure made of grooved megatiles with wavelength shifting (WLS) fibers imbedded inside the grooves. The coverage extends to η = 3.0 and is hermetic with very few gaps. The 1995 test beam data was taken inside a 3 tesla magnet showed that it will work in a magnetic field, but will require a tail catcher inside the muon system.

A system, RESURX, which is inexpensive to implement, has been developed and used to increase the efficiency of an automatic data processing system of a large experiment in a bubble chamber. The system includes a storage display CRT either connected to a dedicated small computer or as a time-sharing terminal of a large computer. Human intervention is accomplished by commands entered via the CRT keyboard. The RESURX system computer codes, written almost completely in FORTRAN, are modular in nature, transportable, and easily modified as a diagnostic or production tool for other applications which involve digitized trajectories. The design of the system and processing results are presented.

We report data on proton-nucleon collisions obtained on Fermilab experiment E711, in which high transverse momentum hadrons are produced near 90\ifmmode^\circ\else\textdegree\fi{} in the proton-nucleon center of mass forming high mass states, using an 800 GeV/c proton beam on targets of beryllium, aluminum, iron, and tungsten. The data presented cover the mass range from 7 to 15 GeV/${\mathit{c}}^{2}$, the three dihadron charge states ++, +-, and --, and parton-parton scattering angles up to ${cos\ensuremath{\theta}}^{*}=0.50$. We present the differential mass dihadron cross section, as well as the angular and charge dependence of the measurement. The cross section as a function of the parton-parton scattering angle for the three charge states is shown to vary linearly with the value of the atomic weight. While the angular distributions are shown to be independent of the target type, a small dependence on the charge state of the distributions is observed. The data are shown to be in good agreement with extrapolations from previous measurements and phenomenological QCD calculations.

This research and development on the grooving methods for the scintillating tiles of the SDC calorimeter was done to maximize the light output of scintillator plates and improve the uniformity among tiles through machining procedures. Grooves for wavelength shifting fibers in SCSN-81 can be machined from 10,000 to 60,000 RPM with a feed rate of more than 30 cm/min if the plate is kept cool and the chips are removed quickly by blowing dry, cold, clean air over the cutting tool. BC499-27, a polystyrene-based scintillator, is softer and more difficult to machine. It allows a maximum rotation speed of 20,000 RPM and a maximum feed rate of 15 cm/min. A new half-keyhole shape was used for the grooves, allowing safer, faster top-loading of the fibers. Three hundred tiles were machined, achieving a standard deviation of the light output of less than 7%.

The average number of charged pions produced in ${\ensuremath{\pi}}^{+}d$ reactions at 15-GeV/c ${\ensuremath{\pi}}^{+}$ momentum is 3.6\ifmmode\pm\else\textpm\fi{}0.1 and the average number of ${\ensuremath{\pi}}^{0}$'s is 1.9\ifmmode\pm\else\textpm\fi{}0.2. The average number of ${\ensuremath{\pi}}^{0}$'s produced is essentially independent of the number of charged pions. About 45% of the events have four or more charged pions in the final state. The exclusive final states with four or more charged pions with zero or one ${\ensuremath{\pi}}^{0}$ are presented and compared with modified phase-space background computations. Other than the well-known resonances, such as the ${\ensuremath{\rho}}^{0}$, no new peaks have been observed. Coherently produced multipion systems with up to seven pions are also discussed. Detailed cross-section information for every final state is presented.

Optical fibers are used extensively in high energy physics, as well as in communication. Fibers in medium and high radiation environments show considerable damage. This damage can be quantified as a reduction in the transmission length, which is a function of the transmitted wavelength. The primary observed damage in a fiber is due to the cladding material. Damage is observed even at low levels of irradiation. Quartz fibers damage less than plastic fibers.

A high-statistics search for the production of narrow $\overline{p}p$ states with a $\overline{p}$ beam at 5 GeV/c finds no evidence for such states from threshold up to 2.3 GeV. In particular, we set an upper limit (95% C.L.) of 9 nb for any state below 1.95 GeV with $\ensuremath{\Gamma}\ensuremath{\le}5$ MeV in the reaction $\overline{p}p\ensuremath{\rightarrow}\overline{p}p{\ensuremath{\pi}}^{0}$. Comparable limits are set for the reaction $\overline{p}p\ensuremath{\rightarrow}\overline{p}p(\ensuremath{\rho}+\ensuremath{\omega})$ and inclusive $\overline{p}p$ production.

We have performed a partial-wave analysis of the K+KOS π− system produced in the reaction K−p → K+K0S π− Λ/Σ at 8 GeV/c. We present results of a preliminary analysis of approximately 2000 events in the KKπ mass range 1.24–1.64 GeV, with 0.0 < −t < 1.4 GeV2. In the 1.28 GeV mass region, we observe a small JPG = 0−+ contribution but little indication of a 1++ wave. We observe a large enhancement of events at the threshold of KK∗ production. Above this threshold the JPG = 1+−, 1++ and 0−+ waves all contribute, and we see evidence for a 1+− resonance below the KK∗ threshold.

Walter Selove, an emeritus professor of physics at the University of Pennsylvania, passed away on 24 August 2010 in Wynnewood, Pennsylvania. An experimental high-energy physicist and an expert in electronic detection systems, he made significant discoveries with bubble chambers and spectrometers. His research career spanned more than 50 years, and he is credited with five patents and one particle discovery.Selove was born on 11 September 1921 in Chicago and studied physics at the University of Chicago, where he obtained a BS degree in 1942. World War II interrupted his studies, and like many other young physicists at the time, he contributed to the war effort; he worked on radar development at MIT. Selove used to tell his graduate students in the early 1960s stories about how everyone at MIT felt motivated to do their utmost for the war effort and how he was often pleasantly surprised when he asked the machine shop workers to build some complicated hardware and would get the finished product the next day.After the war Selove went back to the University of Chicago, where he studied under Enrico Fermi and Edward Teller. Like Fermi, Selove developed a reputation for his back-of-the-envelope calculations. He obtained his PhD degree in 1949 with a thesis titled "A Rotating-Shutter Time-of-Flight Neutron Spectrometer for the Resonance Region." He then used the detector he made for his thesis to study several nuclear resonances. He joined Harvard University as an instructor in 1950 and in 1952 became an assistant professor there. On 18 December 1955 he married Fay Ajzenberg, herself a renowned nuclear physicist. Selove was a great support to his wife at a time when the physics community had biases against women.In 1957 Selove joined the physics department faculty at the University of Pennsylvania as an associate professor; he became a professor in 1961 and 31 years later was made an emeritus professor. Even after retiring, he continued to work on various high-energy physics experiments.Even though his background was in nuclear physics, Selove and three other experimental physics faculty members at Penn created a strong high-energy physics program. Selove was an electronics wizard, and the experiments in which he was a crucial member often benefited from his design ability. One of the first users of computers in high-energy physics, he started with the Univac and then used a series of other systems.Selove began his high-energy physics career performing counter experiments at Brookhaven National Laboratory. In 1961 he realized that bubble-chamber physics was a much better way to study meson resonances. With eight graduate students, including two of us (the Hagopians), Selove studied meson resonances for the next dozen years. With resonances being announced frequently, it was an exciting time in physics. In 1962, using the lab's 20-inch bubble chamber, his group found a new π+π− resonance at about 1260 MeV. Selove told us that when he married Fay, he promised to name the first particle he discovered after her. So we named the particle the fayon, or f2, with the 2 designating the particle's spin. We are happy that the name has stayed, even though many other resonances were renamed to bring order to the naming chaos.Selove also worked at the Princeton–Pennsylvania Accelerator rapid-cycling bubble chamber and observed for the first time the predicted interference between the production of ρ and ω mesons. His bubble-chamber program was one of the first to use the Hough–Powell device, an automated computerized instrument that measured the particle tracks on film with a tiny light source. In total he advised 12 PhD students, many of whom have had successful science careers.Bubble-chamber physics was exciting, but only resonances with large cross sections could be observed. So in the early 1970s, Selove switched back to counter experiments, working with colleagues at Brookhaven and then at Fermilab. In the 1980s, with groups from the University of Wisconsin, Fermilab, and Lehigh University, he conducted a series of experiments using calorimeters that he and his colleagues had developed to study high-momentum-transfer jets that yielded information on quarks and gluons. Selove was one of the original designers of the D0 collider experiment at Fermilab. Later he switched to studying CP violations, and with researchers from 18 other institutions, he studied the B meson. For that experiment he and his group at Penn were the prime movers of the silicon tracker, trigger electronics, and the muon trigger. His last experimental effort, BTeV at Fermilab, was canceled in 2005 by the US Department of Energy before construction began.Walter Selove was passionate about physics. He argued strongly for what he believed was right and often buttressed his views with quick calculations. But in the infrequent instances when he was wrong, good arguments could persuade him to change his mind. He wanted to know every detail of an experiment. He treated his students, collaborators, and staff as colleagues and worried about their well-being. He was a scholar and a gentleman who will be dearly missed by his wife, his students, and his many friends and collaborators.Walter SelovePPT|High resolution© 2011 American Institute of Physics.

The selection of the sigma design for the plate-fiber modules of the SSC calorimeter has reduced by a factor of two the number of fiber ends that will be read directly by photomultiplier tubes. With this design, only one of the ends of a fiber will be connected to a readout channel. In order to avoid wasting the light coming from the other end of the fiber inside the plate, mirroring techniques such as sputtering and painting are being studied. The sputtering and/or painting of optical fibers such as BCF91A considerably increases the light output of the plate-fiber system.

It is shown from experimental data that the extrapolated cross section for the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}n$ at 2.3 GeV/c is not only nonzero at $t=0$, but negative. This is in contrast with higher-energy results where the cross section at $t=0$ is positive. One-pion-exchange calculations modified by absorptive corrections give results in general agreement with these experiments.

The ${K}_{S}{K}_{S}$ mass spectrum is studied in a ${\ensuremath{\pi}}^{+}d$ experiment at 15 GeV/c. Two separate mass enhancements at (1047\ifmmode\pm\else\textpm\fi{}10) and (1190\ifmmode\pm\else\textpm\fi{}10) MeV are observed. The lower mass enhancement is most likely associated with the ${S}^{*}$ and the $\ensuremath{\delta}$ while the one at 1190 MeV could be a new resonance or the ${A}_{1.5}$. Neither enhancement is produced peripherally. An interesting interpretation of this nonperipherality is that the decay of the ${S}^{*}$ or $\ensuremath{\delta}$ is dependent on the charge of the beam meson.

The production of ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ events allows the study of pure $I=1$ exchange without the complicating presence of the $\ensuremath{\Delta}(1236)$ which appears with proton targets. A total of 4218 events, corresponding to 8.5 events/\ensuremath{\mu}b, were analyzed from an exposure of the SLAC 82-inch deuterium bubble chamber. The low-mass resonances [$\ensuremath{\eta}$, $\ensuremath{\omega}$, ${A}_{2}$, and $\ensuremath{\omega}(1675)$] are clearly observed. In addition, enhancements due to possible higher-mass resonances are observed by using the technique of ${p}_{\ensuremath{\perp}}$ cuts.

Three types of optical fibers are used in high energy physics experiments. Scintillating fibers are used mostly for tracking. Wavelength shifting (WLS) fibers to get the signal out from scintillating tiles, which are used often in calorimetry. The third type of optical fibers are clear, typically made of quartz where the Cerenkov radiation in the quartz fiber is used to measure energy in calorimeters. Quartz fibers are normally used in high radiation areas.

We have performed a partial wave analysis of the K+K0Sπ− system produced in the reaction π−p → K+K̄0π−n at GeV/c. We present the mass dependent fits to the PWA results for the waves JPG(isobar)=0−+(α0), 0−+(K*), 1++(α0) and 1++(K*).

We report the results of a study of \ensuremath{\rho} and \ensuremath{\omega} production in ${\ensuremath{\pi}}^{+}$p interactions at 15.7 GeV/c. The SLAC hybrid bubble-chamber facility was used to study reactions in which neutral particles are produced. Three tantalum plates inside the 40-in. bubble chamber and a large array of lead glass downstream of the chamber provided photon detection over a large solid angle. Final states with two neutral particles have been isolated with kinematic fits in which neutral pions were reconstructed in the plates and lead glass. Data from an earlier untriggered ${\ensuremath{\pi}}^{+}$p bubble-chamber experiment at 15 GeV/c were used to obtain samples of events in channels which did not trigger the hybrid system. Cross sections for \ensuremath{\rho} and \ensuremath{\omega} production are given for several exclusive final states. Relative \ensuremath{\rho} and \ensuremath{\omega} production rates are studied. The ratio of nondiffractive \ensuremath{\omega} to ${\ensuremath{\rho}}^{0}$ production is measured to be \ensuremath{\omega}/${\ensuremath{\rho}}^{0}$=0.44\ifmmode\pm\else\textpm\fi{}0.07. We estimate the inclusive \ensuremath{\omega} cross section to be 1.9\ifmmode\pm\else\textpm\fi{}0.3 mb. The results are compared to the Lund model of low-${p}_{T}$ hadronic reactions.

This paper has been withdrawn because it has not been vetted by CMS

Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics ApplicationsAstroparticle, Particle and Space Physics, Detectors and Medical Physics Applications, pp. 348-352 (2006) No AccessTHE HADRON CALORIMETER OF THE CMS EXPERIMENT AT THE LARGE HADRON COLLIDERVASKEN HAGOPIANVASKEN HAGOPIANDepartment of Physics, Florida State University, Tallahassee, Florida, 32306, USAhttps://doi.org/10.1142/9789812773678_0057Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: The construction of the Hadron Calorimeter is now complete. The major components of the detector have been assembled and are now in the process of installation, integration and calibration. The hadron calorimeter inside the CMS detector is made of scintillator and copper absorber covering the |η| range of 0 to 3.0. The forward calorimeter made of quartz fibers and iron absorber covers the |η| range of 3.0 to 5.0. Segments of the hadron calorimeter have been tested in the CERN test beam with electrons, µ's and π's. For the CMS HCAL Collaboration. FiguresReferencesRelatedDetails Recommended Astroparticle, Particle and Space Physics, Detectors and Medical Physics ApplicationsMetrics History PDF download

The authors propose to study Kp and {bar K}p interactions in the energy regions immediately above those now accessible by exposing the NAL large liquid hydrogen bubble chamber to a neutral K{sub L}{sup o} beam.

Fabrication of printed circuit boards (PCBs) in high-radiation areas requires new technologies. The CMS detector in the CERN Large Hadron Collider will have portions in high-radiation environment. The preshower detector in front of the endcap electromagnetic calorimeter is such an area. During the past several years, the emphasis has been put on the research and development of individual components of the preshower detector. Several prototypes of PCBs were manufactured on ceramic substrates. The final prototype was a high-quality product with the ceramic board meeting all specifications, including the adherence of metallic pastes, the resistivity of the metallic lines and the precision of the laser cutting. The Yerevan Physics Institute in collaboration with the MARS Factory, Rubin L. Tech. JSC and Yerevan Telecommunication Research Institute made 4.500 units of the ceramics PCBs and are now being incorporated in the preshower detector. This article describes in detail the R&D for the technology of thick film printing on a ceramic substrate with different pastes and the precise cutting of ceramic plates by a laser.

Search for fractionally charged particles of charge 1 3 ze with z in the range of 4 to 4. Production is through collisions of the primary proton beam (200 GeV or higher) with nucleons in a target.The detection method is a hydrogen bubble chamber where fractionally charged particles in the beam will have an ionization less than minimum defined for z = 1.We propose an exposure of 10,000 pictures with a negatively charged beam and 10,000 pictures with a positively charged beam, both unseparated.'w. F. Baku r £!.

Author(s): Birge, Robert W.; Ely, Robert P.; Gidal, George; Hagopian, Vasken; Kalmus, George E.; Powell, Wilson M.; Billin, Kelvin; Bullock, Frederick; Esten, Michael J.; Govan, M.; Henderson, Cyril; Knight, William J.; Miller, David J.; Stannard, F. Russell; Tovey, Stuart; Treutler, Ortwin; Camerini, Ugo; Cline, David; Fry, William F.; Haggerty, Herman; March, Robert H.; Singleton, William J.

Author(s): Ely, Robert P.; Gidal, George; Hagopian, Vasken; Kalmus, George E.; Billing, Kelvin; Bullock, Frederick W.; Esten, Michael J.; Govan, M.; Henderson, Cyril; Knight, William L.; Stannard, F. Russell; Treutler, Ortwin; Camerini, Ugo; Cline, David; Fry, William F.; Haggerty, Herman; March, Robert H.; Singleton, William J.

The data from π− + p ⇒ ρ0 + n and π− + p ⇒ ρ− + p at 2.3 GeV/c is consistant with a dip in dσ/dt at t∼ − 0.6 (GeV/c)2 for ρ− production and a break at t∼ − 0.6 (GeV/c)2 for ρ0 production, in agreement with theoretical predictions and some other experiments.

From a study of 15-GeV/c ${\ensuremath{\pi}}^{+}$-deuterium interactions obtained in an 890 000-picture exposure in the SLAC 82-inch bubble chamber, evidence is presented for at least two broad dipion states beyond the $g(1680)$ region. These states appear in the spectrum representing highly peripheral interactions, and in the spectra obtained by eliminating those interactions for which the transverse momentum of each pion is less than a specified minimum value. Further, examination of the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\mathrm{MM}$ (missing mass) spectrum from the reaction ${\ensuremath{\pi}}^{+}n\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}(\mathrm{MM})$ indicates that agreement with the previously obtained branching ratios is possible only if higher-mass dipion states are present. Evidence is also presented which suggests a finite decay probability of the $g$ (or a state of similar mass) into ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\eta}$ and/or ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\eta}}^{\ensuremath{'}}$.

The electro-optical interfaces for the central and endcap calorimeters of the CMS experiment at the CERN Large Hadron Collider are readout boxes that receive optical signals via fiber-optic waveguides from the calorimeter scintillator megatiles that comprise the active elements of the detector and decode these signals for energy measurement. The phototransducers housed within the readout boxes are Hybrid Photodiodes (HPDs) which detect and amplify the optical signals. Digitization is provided by preamplifiers or by QIE (Charge, Integration, and Encode) chips. Output signals am then transmitted from the readout boxes to Trigger/DAQ systems located off-detector. Design concepts and construction details are presented for the first pre-production-prototype readout boxes.

The CMS Hadron Calorimeter is designed to measure hadron jets, single hadrons and single ’s. The Central Barrel and the two End Caps, made of brass and scintillators cover the range of 0.0 to 3.0. The two Forward Calorimeters made of iron and quartz bers extend the range to 5.0. Scintillators are also placed outside of the magnet coil, within the muon system to measure the energy leakage from the Central Barrel. The construction of the calorimeter is about 50% complete. Several design changes were made to simplify the calorimeter and reduce the cost. The longitudinal segmentation of the central barrel and end caps was reduced by one unit. The quartz ber diameter was doubled from 300 to 600 microns. Improvements were made to the Hybrid Photodetectors (HPD) and various other components. The special purpose ADC (QIE) and other electronics are in prototype stage.

The Hadron Calorimeter of the CMS detector for the CERN LHC accelerator is designed to measure hadron jets as well as single hadrons. It has six segments. The central barrel made of brass and scintillators covers the |η| range of about 0 to 1.3. Two End Caps, also made of brass and scintillators extends the |η| range to 3.0. Two Forward calorimeters made of iron and quartz fibers cover the range 3.0 to 5.0. Since the barrel portion of the calorimeter is only 6.5 interaction lengths, the outer barrel will sample, by scintillators, outside the magnet coil and cryostat. Progress has been made on all subsystems and prototypes have been built. We now have a better understanding of magnetic field effects on calorimeters.

A search for the U(3.1) resonance decaying into {anti {lambda}}p{pi}'s final states has been performed with negative results. The cross section upper limits are between 10 and 25 nanobarns. These cross sections are one or two order of magnitude lower than expected from previous results. Mass spectra of various final states are presented. 7 refs., 4 figs., 1 tab.

The NA34 (HELIOS) calorimeter has measured e/{pi} {congruent} 1.1 in a uranium/liquid argon calorimeter with a shaping time of 135 nsec. Lead may be a viable alternative, but e/{pi} must first be measured at fast shaping times in lead. We re preparing to measure e/{pi} at momenta ranging from 0.5 to 20 GeV/c and with shaping times of 50, 100 and 150 nsec.

We have performed a partial‐wave analysis of the K+K̄oπ− system produced in the reaction π−p→K+K̄oπ−n at 8.0 GeV/c. We find that the D(1285) is a JPG=1++ state coupling predominantly to a δπ decay channel, while the E(1420) peak consists mostly of a JPG=0−+ wave with a substantial δπ decay mode. There is little evidence of a 1++ resonance at the E mass.

A partial wave analysis and a Dalitz plot analysis of high-statistics data from reaction ..pi../sup -/p ..-->.. K/sup +/K/sub S/..pi../sup -/n at 8.0 GeV/c show that the D(1285) is a J/sup PG/ = 1/sup + +/ state and the E(1420) a J/sup PG/ = 0/sup - +/ state both with a substantial delta..pi.. decay mode. The 1/sup + +/ K*anti K wave exhibits a rapid rise near threshold but no evidence of a resonance in the E region. The assignment of J/sup PG/ = O/sup - +/ to the E is confirmed from a Dalitz-plot analysis of the reaction pp ..-->.. K/sup +/K/sub S/..pi../sup -/X/sup 0/. 11 refs., 5 figs.