P. Rumerio

The cross section for the reaction $\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{e}^{+}{e}^{\ensuremath{-}}$ has been measured at $s=8.8,$ $10.8,$ $12.4,$ $13.1,$ and $14.4 {\mathrm{GeV}}^{2}$ by Fermilab experiment E835. A non-magnetic spectrometer is used to identify the ${e}^{+}{e}^{\ensuremath{-}}$ final states generated by the antiproton beam intersecting an internal hydrogen gas jet target. From the analysis of the 144 observed events, new high-precision measurements of the proton magnetic form factor for timelike momentum transfers are obtained.

Fermilab experiment E835 has measured the cross section for the reaction p̄p→e+e− at s=11.63, 12.43, 14.40 and 18.22 GeV2. From the analysis of the 66 observed events new high-precision measurements of the proton magnetic form factor are obtained.

We report evidence for the hc state of charmonium in its ηcγ decay mode and lack of evidence in the J/ψπ0 mode. We studied these channels in p¯p annihilations near the center of gravity of the PJ3 states, where the hc was reported in the J/ψπ0 mode by E760, our previous experiment, at 3526.2±0.15±0.2 MeV, with ΓR≤1 MeV. We observe an event excess in the ηcγ mode near 3526 MeV. Testing the null hypothesis of a linearly varying background cross section against the alternate hypothesis that includes a resonance near 3526 MeV, we reject the null hypothesis with P∼0.001. The resonance mass is 3525.8±0.2±0.2 MeV and the resonance width ≤1 MeV. We estimate 10.0±3.5<Γp¯pBηcγ<12.0±4.5 eV, corresponding to fixed values 0.5<ΓR<1.0 MeV. We find no event excess within the search region in the J/ψπ0 mode.4 MoreReceived 13 May 2005DOI:https://doi.org/10.1103/PhysRevD.72.032001©2005 American Physical Society

We report on a study of the angular distributions in the radiative decay of the χc1 and χc2 states formed in p¯p annihilations. These distributions depend on the dynamics of the formation process and the multipole structure of the radiative decay. Using 2090 χc1 and 5908 χc2 events, we have measured the fractional magnetic quadrupole amplitude to be a2(χc1)≃M2/E1=0.002±0.032, and a2(χc2)=−0.093−0.041+0.039. We have also measured the square of the helicity 0 fractional amplitude in the χc2 formation process to be B02=0.13±0.08. Received 3 July 2001DOI:https://doi.org/10.1103/PhysRevD.65.052002©2002 American Physical Society

Advanced Series on Directions in High Energy PhysicsThe High Luminosity Large Hadron Collider, pp. 67-99 (2024) Open AccessChapter 3: Upgrade of the Experimental Detectors for High Luminosity LHCF. Hartmann, B. Hippolyte, F. Lanni, T. Nayak, C. Parkes, and P. RumerioF. HartmannKarlsruhe Institute of Technology, 76131 Karlsruhe, Germany, B. HippolyteUSIAS - Université de Strasbourg, 67081, France and CERN, Switzerland, F. LanniBrookhaven National Laboratory, Upton, NY 11973, USA, T. NayakNational Institute of Science Education and Research, Bhubaneswar, Odisha 752050, India and CERN, Switzerland, C. ParkesUniversity of Manchester, Manchester M13 9PL, UK, and P. RumerioUniversity of Alabama, AL 35487, USA and Università di Torino, 10124, Italyhttps://doi.org/10.1142/9789811278952_0003Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: The HL-LHC upgrade plans of ALICE, ATLAS, CMS and LHCb are briefly outlined in this chapter. FiguresReferencesRelatedDetails Recommended The High Luminosity Large Hadron ColliderMetrics History Information© Oliver S Brüning and Lucio RossiThis is an open access article published by World Scientific Publishing Company. It is distributed under the terms of the Creative Commons Attribution 4.0 (CC BY) License.PDF download

The resonance parameters of the χc0, the 13P0 state of charmonium, have been measured at the Fermilab Antiproton Accumulator in the reaction p̄p→χc0→γJ/ψ→γ(e+e−). A large data sample collected during the year 2000 run yields the results: M(χc0)=3415.4±0.4±0.2 MeV/c2, Γ(χc0)=9.8±1.0±0.1 MeV, B(χc0→p̄p)×B(χc0→γJ/ψ)×B(J/ψ→(e+e−))=(1.61±0.11±0.08)×10−7. Taking B(χc0→γJ/ψ) and B(J/ψ→e+e−) from the literature, we obtain B(χc0→p̄p)=(4.1±0.3+1.6−0.9)×10−4 and Γ(χc0→p̄p)=(4.0±0.4+1.6−0.9) keV.

We report the branching ratios of the ${\ensuremath{\chi}}_{c2}{(1}^{3}{P}_{2})$ and ${\ensuremath{\chi}}_{c0}{(1}^{3}{P}_{0})$ charmonium resonances to two photons using event samples collected by Fermilab experiment E835 in the reactions $\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\chi}}_{c2}{(1}^{3}{P}_{2})[{\ensuremath{\chi}}_{c0}{(1}^{3}{P}_{0})].$ Our result for the ${\ensuremath{\chi}}_{c2}$ is $B({\ensuremath{\chi}}_{c2}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})=(1.35\ifmmode\pm\else\textpm\fi{}0.25\ifmmode\pm\else\textpm\fi{}0.12)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$ We set a 95% upper limit for the ${\ensuremath{\chi}}_{c0}$ branching ratio $B({\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})$ at $2.09\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$

We provide a comprehensive description of experiment E835 at Fermilab, a high-precision experimental study of charmonium bound states. The c̄c states are formed in p̄p annihilations of cooled antiprotons stored in the Fermilab Antiproton Accumulator using a dense internal hydrogen gas-jet target. We describe the experimental strategies adopted for detecting the tiny c̄c resonant signals in the huge non-resonant hadronic background, and for measuring resonance parameters with high precision.

We present new precision measurements of the ψ(2S) total and partial widths from excitation curves obtained in antiproton–proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the ψ(2S) meson through the processes p¯p→e+e− and p¯p→J/ψ+X→e+e−+X. We measure the width to be Γ=290±25(sta)±4(sys)keV and the combination of partial widths Γe+e−Γp¯p/Γ=579±38(sta)±36(sys)meV, which represent the most precise measurements to date.

The resonance parameters of the charmonium ground state, ηc(11S0), have been measured by means of the reaction p̄p→ηc→γγ. The mass and total width are determined to be 2984.1±2.1±1.0 MeV/c2 and 20.4+7.7−6.7±2.0 MeV, respectively. The product of branching ratios B(p̄p→ηc)B(ηc→γγ) is determined to be 22.4+3.8−3.7±2.0×10−8, from which B(ηc→γγ)=1.87+0.32+0.95−0.31−0.50×10−4, and Γ(ηc→γγ)=3.8+1.1+1.9−1.0−1.0 keV are derived using B(ηc→p̄p)=(12±4)×10−4 from the literature.

We have studied the 3PJ (χc) states of charmonium in formation by antiproton–proton annihilations in experiment E835 at the Fermilab Antiproton Source. We report new measurements of the mass, width, and B(χcJ→p¯p)Γ(χcJ→J/ψ+anything) for the χc1 and χc2 by means of the inclusive reaction p¯p→χcJ→J/ψ+anything→(e+e−)+anything. Using the subsample of events where χcJ→γ+J/ψ→γ+(e+e−) is fully reconstructed, we derive B(χcJ→p¯p)Γ(χcJ→J/ψ+γ). We summarize the results of the E760 (updated) and E835 measurements of mass, width and B(χcJ→p¯p)Γ(χcJ→J/ψ+γ) (J=0,1,2) and discuss the significance of these measurements.

We report on a search by Fermilab experiment E835 for the η′c (21S0) charmonium resonance in the process ¯p→pη′c→γγ. No signal was observed and, based on 34 pb−1 integrated luminosity, we determine the following upper limits (90% confidence level) to the product of the branching ratios for a resonance mass in the region 3575–3660 MeV/c2: Br(η′c→¯pp)×Br(η′c→γγ)<12.0×10−8 for Γ=5 MeV; <5.9×10−8 for Γ=10 MeV; <4.8×10−8 for Γ=15 MeV. Combining the present data with those of the predecessor experiment, E760, the upper limits become 8.0×10−8, 5.0×10−8, and 4.5×10−8, respectively. In the restricted region 3589–3599 MeV/c2, where a candidate was reported by the Crystal Ball experiment, we obtain the following limits from the combined E760–E835 experiments: Br(η′c→¯pp)×Br(η′c→γγ)<5.6×10−8 for Γ=5 MeV; <3.7×10−8 for Γ=8 MeV. A comparison of these with other experimental results is presented.Received 18 January 2001DOI:https://doi.org/10.1103/PhysRevD.64.052003©2001 American Physical Society

We present the first measurement of the angular distribution for the exclusive process p¯p→ψ(2S)→e+e− based on a sample of 6844 events collected by the Fermilab E835 experiment. We find that the angular distribution is well described by the expected functional form dNdcosθ∗∝1+λcos2θ∗, where θ∗ is the angle between the antiproton and the electron in the center of mass frame, with λ=0.67±0.15(stat)±0.04(sys). The measured value for λ implies a small but non-zero ψ(2S) helicity 0 formation amplitude in p¯p, comparable to what is observed in J/ψ decays to baryon pairs.

The resonance parameters of χc0, the 31P0 resonance of charmonium, have been measured at the Fermilab Antiproton Accumulator by means of the reaction ¯pp→χc0→γJ/ψ→γ(e+e−). The results are M(χc0)=3417.4+1.8−1.9±0.2MeV/c2, Γ(χc0)=16.6+5.2−3.7±0.1MeV, and Γ(χc0→¯pp)×B(χc0→J/ψγ)×B(J/ψ→e+e−)=2.89+0.67−0.53±0.14eV. Using known branching ratios we also obtain Γ(χc0→¯pp)=8.0+1.9+3.5−1.5−1.9keV. These results are discussed in relation to the other χcJ states and to theoretical predictions.Received 3 June 1999DOI:https://doi.org/10.1103/PhysRevLett.83.2902©1999 American Physical Society

Fermilab experiment E835 has observed (-)pp annihilation production of the charmonium state chi(c0) and its subsequent decay into pi(0)pi(0). Although the resonant amplitude is an order of magnitude smaller than that of the nonresonant continuum production of pi(0)pi(0), an enhanced interference signal is evident. A partial wave expansion is used to extract physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate the expansion. Both are accessed by L=1 in the entrance (-)pp channel. The product of the input and output branching fractions is determined to be B((-)pp-->chi(c0))xB(chi(c0)-->pi(0)pi(0))=(5.09+/-0.81+/-0.25)x10(-7).

We report on the decay to two photons of the χ c 0 (1 3 P 0 ) charmonium resonance formed in pp interactions at Fermilab experiment E835.We have measured the product of branching ratios BR(χ c 0 → pp) × BR(χ c 0 → γ γ ) = (6.52 ± 1.18(stat) +0.48 -0.72 (sys)) × 10 -8 .Using values from the 2002 PDG, this measurement leads to the partial width Γ (χ c 0 → γ γ ) = 2.9 ± 0.9 keV.

We have determined the following ${\ensuremath{\psi}}^{\ensuremath{'}}$ branching ratios using the large event sample collected by Fermilab experiment E835 in the reaction $p\overline{p}\ensuremath{\rightarrow}{\ensuremath{\psi}}^{\ensuremath{'}}:$ $\mathcal{B}({\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}})=(7.4\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3},$ $\mathcal{B}({\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(18.7\ifmmode\pm\else\textpm\fi{}0.9\ifmmode\pm\else\textpm\fi{}1.3)%$ and $\mathcal{B}({\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\eta})=(4.1\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}0.5)%.$

I present preliminary results on the search for $h_c$ in its $\eta_c\gamma$ and $J/\psi\pi^0$ decay modes. We observe an excess of \eta_c\gamma$ events near 3526 MeV that has a probability ${\cal P} \sim 0.001$ to arise from background fluctations. The resonance parameters are $M=3525.8 \pm 0.2 \pm 0.2 $MeV, $\Gamma\leq$ 1 MeV, and $10.6\pm 3.7\pm3.4(br) < \Gamma_{\bar{p}p}B_{\eta_c\gamma} < 12.8\pm 4.8\pm4.5(br) $eV. We find no event excess within the search region in the $J/\psi\pi^0$ mode.

Two layers of proportional drift tubes (aluminum mylar straws) are staggered in two cylindrical light chambers to measure charged particles’ azimuthal angle. To stand the high rates (∼10kHz/cm2) and minimize the pile-up of the high luminosity experiment 835 at FNAL, a fast ASIC Amplifier-Shaper-Discriminator (ASD-8B) was chosen. The front-end electronics, designed exclusively with SMD components, was mounted on the downstream end plug of each chamber to avoid oscillations and noise. Design, construction and operational performances of these detectors are presented.

I present preliminary results on the search for hc in its ηcγ and J/ψπ0 decay modes. We observe an excess of ηcγ events near 3526 MeV that has a probability P∼0.001 to arise from background fluctations. The resonance parameters are M=3525.8±0.2±0.2MeV, Γ⩽1MeV, and 10.6±3.7±3.4(br)<Γp¯pBηcγ<12.8±4.8±4.5(br)eV. We find no event excess within the search region in the J/ψπ0 mode.

Fermilab experiment E835 has studied reactions $\overline{p}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0},{\ensuremath{\pi}}^{0}\ensuremath{\eta},\ensuremath{\eta}\ensuremath{\eta},$ ${\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}}$ and $\ensuremath{\eta}{\ensuremath{\eta}}^{\ensuremath{'}}$ in the energy region of the ${\ensuremath{\chi}}_{c0}({1}^{3}{P}_{0})$ from $3340$ MeV to $3470$ MeV. Interference between resonant and continuum production is observed in the ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ and $\ensuremath{\eta}\ensuremath{\eta}$ channels, and the product of the input and output branching fractions is measured. Limits on resonant production are set for the ${\ensuremath{\pi}}^{0}\ensuremath{\eta}$ and ${\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}}$ channels. An indication of interference is observed in the $\ensuremath{\eta}{\ensuremath{\eta}}^{\ensuremath{'}}$ channel. The technique for extracting resonance parameters in an environment dominated by continuum production is described.

We have measured several branching ratios for ψ′ decay using the data collected by the FNAL E835 experiment during the year 2000, obtaining B(ψ′→e+e−)=0.0068±0.0001±0.0004, B(ψ′→J/ψπ+π−)=0.292±0.005±0.018, B(ψ′→J/ψπ0π0)=0.167±0.005±0.014, and B(ψ′→J/ψη)=0.028±0.002±0.002. We also present a measurement of the dipion mass distribution in the decays ψ′→J/ψππ.Received 6 August 2004DOI:https://doi.org/10.1103/PhysRevD.71.032006©2005 American Physical Society

Transformative discovery in science is driven by innovation in technology. Our boldest undertakings in particle physics have at their foundation precision instrumentation. To reveal the profound connections underlying everything we see from the smallest scales to the largest distances in the Universe, to understand its fundamental constituents, and to reveal what is still unknown, we must invent, develop, and deploy advanced instrumentation. Investments in High Energy Physics (HEP) enabled by instrumentation have been richly rewarded with discoveries of the tiny masses of the neutrinos, the origin of mass itself: the enigmatic Higgs boson, and the surprising accelerating expansion of the Universe. What we have learned is remarkable, unexpected, exciting and mysterious; raising many new questions waiting to be answered. The quest to answer them drives innovation that improves the nation's health, wealth, and security, inspiring the public and drawing young people to science. Excellence and innovation come most effectively from diverse teams of people. Success, therefore, depends critically on attracting, engaging, and supporting a diverse cadre of young people to the field, and ensuring an inclusive environment at all levels. The program laid out in the 2014 Particle Physics Projects Prioritization Panel (P5) report "Building for Discovery - A Strategic Plan for U.S. Particle Physics in a Global Context" guides current and near future experiments to exploit these and other discoveries, and the instrumentation innovation they require, to push the frontiers of science into new territory. To explore this territory HEP will soon embark on planning the next generation of experiments. Realizing these experiments will require giant leaps in capabilities beyond the instrumentation of today. Accordingly, now is a pivotal moment to invest in the accelerated development of cost-effective instrumentation with greatly improved sensitivity and performance that will make measurable the unmeasurable, enabling a tool-driven revolution to open the door to future discoveries. Historic scientific opportunities await us, enabled by executing the instrumentation research plan outlined here.

The Hybrid Photodetector (HPD) is a hybrid unit with a single accelerating gap between a common photocathode and an array of PIN diodes. Customised HPDs with 19 channels were used to detect scintillation light from hadron calorimeter in the Compact Muon Solenoid (CMS) experiment. In this paper, we present results on radiation damage studies carried out on the used HPDs in the outer hadron (HO) and the end-cap hadron (HE) calorimeter of the CMS experiment operating at CERN. The calorimeter is made of alternating layers of scintillating tiles and metals, such as brass or iron. The scintillating light was transmitted to the HPDs by means of optical fibres. Due to excessive exposure to scintillation light and ionising radiation during data taking at the Large Hadron Collider, the performance of the HPDs was expected to degrade significantly in the HE detector. Independent studies on radiation damage of these used photosensors were important to assess the degradation in the performance of the calorimeter. Microscopic scans of relative photon detection efficiencies for two HPDs (one each from HO and HE detector) were made using micron resolution optical scanner. The scanner was specially designed and built for microscopic characterisation of photosensors. Imprints of each fibre (∼1 mm in diameter) on the photocathode with varying damage within the same pixel of the HPD were observed. The localised damage of the photocathode was determined to vary with the amount of scintillation (or calibration) light transmitted by optical fibres to the HPD.

Abstract Fermilab experiment E835 studies the direct formation of charmonium states in proton-antiproton annihilations, obtained by intersecting the p beam of the Fermilab Antiproton Accumulator with an internal hydrogen jet target. In this paper we report the preliminary results from the 1996/1997 run, in particular about η c mass and width, search for η ′ c and first observation of the χ 0 state in p p annihilations.

The barrel part of the CMS electromagnetic calorimeter consists of 61,200 lead‐tungstate crystals optically coupled to twice as many avalanche photodiodes. The on‐detector read‐out electronics comprises about 20,000 printed circuit boards and 5000 optical links. The integration and commissioning phase of the 36 supermodules, 1700 crystals each, is flowing steadily at CERN in compliance with the experiment installation schedule. Given the high complexity of the apparatus, each integration step is validated by specific quality controls. It follows a week of pedestal, test‐pulse and laser light monitoring runs, and 10 days of cosmic ray calibration. An automatic analysis of the data provides immediate feedback for possible intervention and verifies the stability and performance of the detector. In addition, a subset of supermodules is undergoing an electron beam calibration while two supermodules are being operated, within a segment of the CMS detector, in a CMS‐like environment during the magnet test.The strategy and procedure aimed to ensure a zero‐fault tolerance in the commissioning of such a highly sophisticated and performing apparatus will be described, along with the operational experience accumulated so far.

Future experiments in high energy and nuclear physics may require large, inexpensive calorimeters that can continue to operate after receiving doses of 50 Mrad or more. The light output of liquid scintillators suffers little degradation under irradiation. However, many challenges exist before liquids can be used in sampling calorimetry, especially regarding developing a packaging that has sufficient efficiency and uniformity of light collection, as well as suitable mechanical properties. We present the results of a study of a scintillator tile based on the EJ-309 liquid scintillator using cosmic rays and test beam on the light collection efficiency and uniformity, and some preliminary results on radiation hardness.

The CMS detector at LHC is equipped with a high precision lead tungstate crystal electromagnetic calorimeter (ECAL). The front-end boards and the photodetectors are monitored using a network of DCU (Detector Control Unit) chips located on the detector electronics. The DCU data are accessible through token rings controlled by an XDAQ-based software component. Relevant parameters are transferred to DCS (Detector Control System) and stored into the Condition DataBase. The operational experience from the ECAL commissioning at the CMS experimental cavern is discussed and summarized.

The electromagnetic calorimeter of the CMS experiment at CERN is an homogeneous calorimeter made of about 80000 Lead Tungstate crystals, that will start to operate at the LHC at the end of 2007. From June to November 2006, ten barrel Supermodules (1700 crystals each) were exposed to beam at CERN SPS, both in standalone and in association with portions of the Hadron Calorimeter. We present the description of the system used to configure and readout the calorimeter during the campaign. The full set of final readout electronics boards was employed, together with the pre-series version of the data acquisition software. During the campaign, the hardware and software concepts for the final system were validated. The system allowed the intercalibration of the ten Supermodules and allowed to perform several important studies of the detector performances, such as energy resolution, response linearity and radiation-hardness.

The quark and lepton sectors of the standard model (SM) are strikingly similar in terms of the number of particles and generations. This hints at a fundamental symmetry existing between the two sectors. Indeed, such a symmetry is part of many beyond-the-SM theories such as composite models [6], technicolor, grand unified SU(5), Pati-Salam SU(4) [7] and E6 superstring-inspired theories. These models give rise to a new class of bosons called leptoquarksLeptoquarks (LQs) that carry both baryon and lepton numbers—a signature of their coupling to quarks and leptons. We perform a dedicated search for pair-producedPair production first generation scalar leptoquarks, resulting in a final state of two electrons and at least two jets, using proton-proton collision data taken at centre-of-mass energy of 13 TeV. The data were recorded by the CMS detector [8] during the 2015 running of the LHC, and correspond to an integratedCMS detector luminosity of 2.6 $${\text {fb}}^{-1}$$ .

The CMS hadron Calorimeter is made of alternating layers of scintillating tiles and metals, such as brass or iron. The original photo detectors were hybrid units with a single accelerating gap called Hybrid Photo Diodes (HPD). Scintillating light was transmitted to the HPDs by means of optical fibers. During data taking at the Large Hadron Collider (LHC), the signal strength of scintillator tiles of detector units in the forward region degraded significantly due to the damage related to the amount of radiation to which the scintillator was exposed to. Scintillators suffer damage when exposed to radiation, however, the amount of damage observed was more than originally estimated. Several HPDs were removed during a detector shut down period. Microscopic scans of relative quantum efficiencies for few of these HPDs were made. The damage of the photocathode was determined to vary with the amount of optical signal transmitted by optical fibers to the HPD. Imprints of each fiber (1 mm) on the photocathode with varying damage within the same pixel were observed. Most of the observed reduction of the calorimeter signal can be attributed to localised damage of the photocathode.

We present new precision measurements of the psi(2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi(2S) meson through the processes pbar p -&gt; e+ e- and pbar p -&gt; J/psi + X -&gt; e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +- 4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp / Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise measurements to date.

The Fermilab E835 Collaboration has studied Charmonium production using a gas jet hydrogen target, the virtually monoenergetic stochastically cooled antiproton beam and a large acceptance shower spectrometer. Until now our studies have featured electromagnetic final states, mostly the e+e− decay of Jψ or ψ′, and γγ decay of ηc, χc0, or χc2. For the first time in hadronic Charmonium production, hadronic annihilation channels have been clearly identified: π0π0 and ηη at the χc0 resonance. This has required a parameterization of the non-resonant partially interfering final state channels. Our studies contribute to a clearer and improved understanding of the pp annihilation process.

The Fermilab E835 Collaboration has studied Charmonium production using a gas jet hydrogen target, the virtually monoenergetic stochastically cooled antiproton beam and a large acceptance shower spectrometer. Until now our studies have featured electromagnetic final states, mostly the e+e− decay of Jψ or ψ′, and γγ decay of ηc, Xc0, or Xc2. For the first time in hadronic Charmonium production, hadronic annihilation channels have been clearly identified: π0π0 and ηη at the Xc0 resonance. This has required a parameterization of the non-resonant partially interfering final state channels. Our studies contribute to a clearer and improved understanding of the pp annihilation process.

E835 can measure the mass and width of resonant states produced in p̄p collisions at center of mass energies which span the spectrum of cc̄ bound states (Charmonium). The experiment began taking data during Autumn, 1996. Results presented here include a measurement of the ηc.

device as the ramp is executed. The 1997 ramps consist of ramp tables for 100 devices. Appendix 1 gives a list of the devices ramped. Most of these devices will still require ramps for the next fixed target run. Future decelerations will also require ramps for the quadrupole magnet shunts that were installed as part of the {gamma}{sub t} upgrade. Additionally, ramps must be constructed for the two skew-sextupole magnets that will be installed during the summer of 1999.