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Production of hadrons and leptons at high p/sub t/ and pairs at high mass

Description: The experiment reported extends to higher beam energy the measurements of high-p/sub t/ particle production and high-mass pair production in N-N collisions, with improved resolution, particle identification, and luminosity. Besides addressing quantum chromodynamics issues, limits are set on the mass and lifetime of the axion. 25 refs., 19 figs. (LEW)
Date: January 1, 1986
Creator: Kaplan, D.M.
Partner: UNT Libraries Government Documents Department

Status of MICE

Description: Muon ionization cooling is the only practical method for preparing high-brilliance beams needed for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) under development at the Rutherford Appleton Laboratory comprises a dedicated beamline to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A first measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating-fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen with RF acceleration. A second spectrometer identical to the first and a particle identification system will measure the outgoing emittance. Plans for measurements of emittance and cooling are described.
Date: November 1, 2008
Creator: Bross, A. D. & Kaplan, D. M.
Partner: UNT Libraries Government Documents Department

Muon Collider/Neutrino Factory: Status and prospects

Description: During the 1990s an international collaboration has been studying the possibility of constructing and operating a high-energy high-luminosity {mu}{sup +}{mu}{sup {minus}} collider. Such a machine could be the approach of choice to extend the discovery reach beyond that of the LHC. More recently, a growing collaboration is exploring the potential of a stored-muon-beam neutrino factory to elucidate neutrino oscillations. A neutrino factory could be an attractive stepping-stone to a muon collider. Its construction, possibly feasible within the coming decade, could have substantial impact on neutrino physics.
Date: January 26, 2000
Creator: Kaplan, D.M.
Partner: UNT Libraries Government Documents Department

Backgrounds to the detection of two-body hadronic B decays

Description: We consider backgrounds to the detection of the two-body hadronic decay modes of neutral B mesons and baryons. The largest background is due to the correlated production of pairs of high-p/sub T/ hadrons in the target, but this can be adequately rejected provided the experimental apparatus has sufficient resolution in mass and decay vertex. Another possible source of background arises from the production and decay of charmed and strange particles. Since these particles can travel considerable distances before decaying, they can give rise to backgrounds which may not be rejectable by means of vertex cut. We have simulated several backgrounds from charm, and we find them to be small compared to the expected level of signal. 8 refs., 1 fig., 2 tabs
Date: January 8, 1988
Creator: Kaplan, D.M.; Peng, Jen-Chieh; Abrams, G.S. & Stockdale, I.E.
Partner: UNT Libraries Government Documents Department

The HyperCP data acquisition system

Description: For the HyperCP experiment at Fermilab, we have assembled a data acquisition system that records on up to 45 Exabyte 8505 tape drives in parallel at up to 17 MB/s. During the beam spill, data are acquired from the front-end digitization systems at {approx} 60 MB/s via five parallel data paths. The front-end systems achieve typical readout deadtime of {approx} 1 {micro}s per event, allowing operation at 75-kHz trigger rate with {approx_lt}30% deadtime. Event building and tapewriting are handled by 15 Motorola MVME167 processors in 5 VME crates.
Date: June 1, 1997
Creator: Kaplan, D.M. & Collaboration, E871
Partner: UNT Libraries Government Documents Department

Issues for high-luminosity fixed-target rare-B-decay experiments

Description: Fermilab E789 is the prototype of a new approach to the study of heavy-quark decays using fixed target. The apparatus acceptance is restricted to charged particles of relatively large momentum emerging at relatively large angles, allowing operation at high interaction rates. At rates up to 10 interactions per RF-bucket, the experiment may have sensitivity at the level of 10{sup {minus}6} per running period for such rare decay modes as B {yields} {pi}{sup +}{pi}{sup {minus}}. Could such an approach be extended to give sensitivity to standard-model CP violation in the beauty sector Since the predicted CP asymmetry in B {yields} {pi}{sup +}{pi}{sup {minus}} is of order 10{sup {minus}1}, this is a particularly attractive mode to consider. The simplest CP asymmetry would be a difference in absolute rates for B{sup 0} {yields} {pi}{sup +}{pi}{sup {minus}} and {ovr B{sup 0}} {yields} {pi}{sup +}{pi}{sup {minus}}, requiring tagging of the b-quark charge for its observation. Assuming a plausible branching ratio of 10{sup {minus}5} for B {yields} {pi}{sup +}{pi}{sup {minus}}, E789 should reconstruct some 30 events per run. In a restricted-acceptance experiment such as E789, the most plausible tagging technique is detection of single muons from semileptonic decay of the B. Since the B semileptonic branching ratios are {approx}10% and the E789 acceptance for muons from B decay is {approx}10%, fewer than 1 tagged event per run would be expected. We are thus looking for at least two orders of magnitude improvement in the produce luminosity {times} acceptance {times} tagging efficiency.
Date: October 1, 1990
Creator: Kaplan, D.M. (Northern Illinois Univ., Dekalb, IL (USA))
Partner: UNT Libraries Government Documents Department

The intergration of liquid and solid muon absorbers into afocusing magnet of a muon cooling channel

Description: This report describes how one can integrate the muonabsorber with the focusing coils of a SFOFO muon cooling channel [1]. Theabsorber material must be a low Z material that reduces the muon momentumwith minimum scattering. The best materials to use for muon ionizationcooling absorbers are hydrogen, helium, lithium hydride, lithium, andberyllium. Hydrogen or helium in an absorber would normally be in theliquid state. Lithium hydride, lithium, and beryllium would normally bein the solid state. This report limits the absorber materials discussedto hydrogen, helium, lithium, and beryllium. In order to achieve the samelevel of ionization cooling with a solid absorber as a liquid hydrogenabsorber, the beta of the muon beam must be reduced more than a factor oftwo. This affects both the designs of the absorber and the magnet aroundit. Reducing the beam beta reduces the momentum acceptance of thechannel. Integration of a liquid hydrogen absorber and solid absorberswith a superconducting focusing solenoid is discussed. The choice ofabsorber material affects the design of the superconducting focusingmagnet and the superconductor that is used to generate the magneticfield.
Date: May 1, 2003
Creator: Green, M.A.; Black, E.L.; Cummings, M.A.; Kaplan, D.M.; Ishimoto,S.; Cobb, J.H. et al.
Partner: UNT Libraries Government Documents Department

Opportunities for high-sensitivity charm physics at Fermilab

Description: The CO initiative under consideration at Fermilab makes feasible a charm experiment reconstructing >10{sup 9} charm decays, four orders - of magnitude beyond the largest extant sample. The experiment might commence data-taking as early as 1999. In addition to programmatic charm physics such as spectroscopy, lifetimes, and QCD tests, it will have significant new-physics reach in the areas of CP violation, flavor-changing neutral-current and lepton-number-violating decays, and D{sup o} {bar D} {bar {sup o}} mixing, and should observe direct CP violation in Cabibbo-suppressed D decays if it occurs at the level predicted by the Standard Model.
Date: July 1, 1996
Creator: Kaplan, D.M.; Burnstein, R.A.; Lederman, L.M.; Rubin, H.A.; Brown, C.N.; Christian, D.C. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the asymmetry in the decay Antiomega+ ---> Antilambda K+ ---> anti-p pi+ K+

Description: The asymmetry in the {bar p} angular distribution in the sequential decay {bar {Omega}}{sup +} {yields} {bar {Lambda}}K{sup +} {yields} {bar p}{pi}{sup +}K{sup +} has been measured to be {bar {alpha}}{sub {Omega}}{bar {alpha}}{sub {Lambda}} = [+1.16{+-}0.18(stat){+-}0.17(syst)]x10{sup -2} using 1.89x10{sup 6} unpolarized {bar {Omega}}{sup +} decays recorded by the Hyper CP (E871) experiment at Fermilab. Using the known value of {alpha}{sub {Lambda}}, and assuming that {bar {alpha}}{sub {Lambda}} = -{alpha}{sub {Lambda}}, {bar {alpha}}{sub {Omega}} = [-1.81{+-}0.28(stat){+-}0.26(syst)]x10{sup -2}. A comparison between this measurement of {bar {alpha}}{sub {Omega}}{bar {alpha}}{sub {Lambda}} and recent measurements of {alpha}{sub {Omega}}{alpha}{sub {Lambda}} made by HyperCP shows no evidence of a violation of CP symmetry.
Date: January 1, 2006
Creator: Lu, L.C.; Burnstein, R.A.; Chakravorty, A.; Chen, Y.C.; Choong, W.S.; Clark, K. et al.
Partner: UNT Libraries Government Documents Department

Nuclear effects in Drell-Yan and quarkonium production in proton-nucleus collisions

Description: A precise measurement of the atomic mass dependence of dimuon production induced by 800 GeV protons incident on targets of {sup 2}H, C, Ca, Fe, and W is reported. The relative Drell-Yan yield per nucleon, R = Y{sub A}/Y{sub 2{sub H}}, is sensitive to modifications of the antiquark sea in nuclei. No effect is seen for the range of target-quark momentum fraction, 0.1 < x{sub t} < 0.3. For x{sub t} < 0.1 the ratio is slightly less than unity for the heavy nuclei. These results are compared with the predictions of EMC models. A depletion of the yield per nucleon from heavy nuclei is observed for both J/{psi} and {psi}{prime} production. This depletion exhibits a strong dependence of x{sub F} and p{sub t}. Within experimental errors the depletion is the same for the J/{psi} and the {psi}{prime}. 41 refs., 6 figs.
Date: January 1, 1990
Creator: Peng, J.C.; Alde, D.M.; Baer, H.W.; Carey, T.A.; Garvey, G.T.; Klein, A. et al.
Partner: UNT Libraries Government Documents Department

Nuclear medium effects on quarks, gluons, and on vector meson production: New insights from dimuon production

Description: A precise measurement of the atomic mass dependence of dimuon continuum and vector-meson production induced by 800 GeV/c protons is reported. Approximately 700,000 muon pairs with dimuon mass M {ge} 3 GeV were recorded from targets of {sup 2}H, C, Ca, Fe, and W. The ratio of Drell-Yan dimuon yield per nucleon for nuclei versus {sup 2}H, R = Y{sub A}/Y{sub 2H}, is sensitive to modifications of the antiquark sea in nuclei. No nuclear dependence of this ratio is observed over the range of target-quark momentum fraction 0.1 < x{sub t} < 0.3. For x{sub t} < 0.1 the ratio is slightly less than unity for the heavy nuclei. These results are compared with predictions of models of the EMC effect. A depletion of the yield per nucleon from heavy nuclei is observed for the J{Psi}, {Psi}{prime}, and {Upsilon} production. This depletion exhibits strong dependence on x{sub f} and p{sub t}. 25 refs., 19 figs., 1 tab.
Date: January 1, 1990
Creator: Leitch, M.J.; Alde, D.M.; Baer, H.W.; Carey, T.A.; Garvey, G.T.; Klein, A. et al.
Partner: UNT Libraries Government Documents Department

Search for CP violation in hyperon decays.

Description: Direct CP violation in nonleptonic hyperon decays can be established by comparing the decays of hyperons and anti-hyperons. For {Xi} decay to {Lambda} {pi} followed by {Lambda} to p{pi}, the proton distribution in the rest frame of Lambda is governed by the product of the decay parameters {alpha}{sub {Xi}} {alpha}{sub {Lambda}}. The asymmetry A{sub {Xi}{Lambda}}, proportional to the difference of {alpha}{sub {Xi}}{alpha}{sub {Lambda}} of the hyperon and anti-hyperon decays, vanishes if CP is conserved. We report on an analysis of a fraction of 1997 and 1999 data collected by the Hyper CP (E871) collaboration during the fixed-target runs at Fermilab. The preliminary measurement of the asymmetry is {Alpha}{sub {Xi}{Lambda}} = [-7 {+-} 12(stat) {+-} 6.2(sys)] x 10{sup -4}, an order of magnitude better than the present limit.
Date: October 25, 2002
Creator: Zyla, Piotr; Chan, A.; Chen, Y.C.; Ho, C.; Teng, P.K.; Choong, W.S. et al.
Partner: UNT Libraries Government Documents Department

Examining CP symmetry in strange baryon decay

Description: Non-conservation of CP symmetry can manifest itself in non-lepton ichyperon decays as a difference in the decay parameter between the strange-baryon decay and its charge conjugate. By comparing the decay distribution in the {Lambda} helicity frame for the decay sequence {Xi}{sup -} {yields} {Lambda}{pi}{sup -}, {Lambda} {yields} p{pi}{sup -} with that of {bar {Xi}}{sup +} decay, E756 at Fermilab did not observe any CP-odd effect at the 10{sup -2} level. The status of a follow-up experiment, HyperCP (FNAL E871), to search for CP violation in charged {Xi}-{Lambda} decay with a sensitivity of 10{sup -4} is also presented.
Date: April 5, 2000
Creator: Luk, Kam-Biu; Collaboration, Fermilab E756; Collaboration, HyperCP; Burnstein, R.A.; Chakravorty, A.; Chan, A. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the LIght Quark Flavor Asymmetry in the Nucleon Sea

Description: The Drell-Yan cross section ratios, s(p+d)/s(p+p), measured in Fermilab E866, have led to the first determination of d(x)/u(x), d(x)-(x), and the integral of d(x)-u(x) for the proton over the range 0.02 &lt; x &lt; 0.345. The E866 results are compared with predictions based on parton distribution functions and various theoretical models. The relationship between the E866 results and the NMC measurements of the Gottfried integral is discussed. The agreement between the E866 results and models employing virtual mesons indicates these non-perturbative processes play an important role in the origin of the d, u asymmetry in the nucleon sea.
Date: July 23, 1998
Creator: Peng, J.C.; Awes, T.C.; Beddo, M.E.; Brooks, M.L.; Brown, C.N.; Bush, J.D. et al.
Partner: UNT Libraries Government Documents Department

Beauty and charm production from Fermilab experiment 789

Description: Experiment 789 is a fixed-target experiment at Fermilab designed to study low-multiplicity decays of charm and beauty. During the 1991 run. E789 collected {approx} 10{sup 9} events using an 800 GeV proton beam incident upon gold and beryllium targets. Analyses of these data include searches for b {yields} J/{psi}+{Chi} decays and {Alpha}- dependence measurements of neutral D meson production. Preliminary results from the 1991 run are presented in this paper.
Date: June 1, 1993
Creator: Jansen, D.M.; Boissevain, J.; Carey, T.A.; Jeppesen, R.G.; Kapustinsky, J.S.; Lane, D.W. et al.
Partner: UNT Libraries Government Documents Department