The transverse profile of electromagnetic showers in a calorimeter made of TΦ 1-00 lead glass was measured at electron energies of 3, 9, and 23 GeV for two configurations of the setup: with and ...without an assembly of passive material being placed in front of the calorimeter. The method for obtaining the shower profile did not require the use of high-precision coordinate detectors. Parameterization of shower profiles by a two-dimensional function with two parameters was proposed. A program for simulating Cherenkov light in a lead glass calorimeter was developed. The experimental data agree with the results of Monte Carlo simulation within the limits of experimental errors.
The Snowmass report on rare processes and precision measurements recommended Mu2e-II and a next generation muon facility at Fermilab (Advanced Muon Facility) as priorities for the frontier. The ...Workshop on a future muon program at FNAL was held in March 2023 to discuss design studies for Mu2e-II, organizing efforts for the next generation muon facility, and identify synergies with other efforts (e.g., muon collider). Topics included high-power targetry, status of R&D for Mu2e-II, development of compressor rings, FFA and concepts for muon experiments (conversion, decays, muonium and other opportunities) at AMF. This document summarizes the workshop discussions with a focus on future R&D tasks needed to realize these concepts.
An observation of Charged Lepton Flavor Violation (CLFV) would be unambiguous evidence for physics beyond the Standard Model. The Mu2e and COMET experiments, under construction, are designed to push ...the sensitivity to CLFV in the mu to e conversion process to unprecedented levels. Whether conversion is observed or not, there is a strong case to be made for further improving sensitivity, or for examining the process on additional target materials. Mu2e-II is a proposed upgrade to Mu2e, with at least an additional order of magnitude in sensitivity to the conversion rate over Mu2e. The approach and challenges for this proposal are summarized. Mu2e-II may be regarded as the next logical step in a continued high-intensity muon program at FNAL.
AIP Conf.Proc.792:291-294,2005 Measurements of the inclusive yields of pi0 mesons in p+p and d+Au collisions
at center of mass energy sqrt(s_NN)=200 GeV and pseudorapidity =4.00 (d
beam direction) ...are reported. The yield for p+p collisions is in general
agreement with perturbative QCD calculations. The d+Au yield is in agreement
with a calculation which models the Au nucleus as a Color Glass Condensate for
forward particle production. The nuclear modification factor derived from the
inclusive yields is qualitatively consistent with models which suppress the
gluon density in nuclei.
Measurements are reported of the production of high energy pi-zero mesons
from the STAR experiment in p+p and d+Au collisions at sqrt(s_NN)=200 GeV and
=4.00 (d beam direction). The inclusive yield ...agrees with perturbative QCD
calculations in p+p collisions, but is found to be reduced in d+Au collisions.
The azimuthal correlations of the forward pi-zero with charged hadrons at
midrapidity agree with PYTHIA in p+p collisions, but are suppressed in d+Au
collisions. The results are consistent with the conjecture that the gluon
density in nuclei is suppressed.
Measurements are reported of the production of high energy pi^0 mesons at
large pseudorapidity, coincident with charged hadrons at mid-rapidity, for
proton+proton and deuteron+gold collisions at ...sqrt{s_{NN}}=200 GeV. The p+p
cross section for inclusive pi^0 production follows expectations from
next-to-leading order perturbative QCD. A suppression of the back-to-back
azimuthal correlations was observed in d+Au, qualitatively consistent with the
gluon saturation picture. Experimental uncertainties regarding the inclusive
measurement are discussed.
The dependence on Q{sup 2} (the negative square of the 4-momentum of the exchanged virtual photon) of the generalised Gerasimov-Drell-Hearn integral for the proton has been measured in the range 1.2 ...GeV{sup 2}<Q{sup 2}<12 GeV{sup 2} by scattering longitudinally polarised positrons on a longitudinally polarised hydrogen gas target. The contributions of the nucleon-resonance and deep inelastic regions to this integral have been evaluated separately. The latter has been found to dominate for Q{sup 2}>3 GeV{sup 2}, while both contributions are important at low Q{sup 2}. The total integral shows no significant deviation from a 1/Q{sup 2} behavior in the measured Q{sup 2} range, and thus no sign of large effects due to either nucleon-resonance excitations or nonleading twist.
Preliminary results of the analyzing power for the production of forward,
high-energy pi0 mesons from collisions of transversely polarized protons at
sqrt(s)=200 GeV from STAR are presented. The ...kinematic ranges covered by the
data are x_F=0.2-0.6 and p_T=1-3 GeV/c. The analyzing power at sqrt(s)=200 GeV
is found to be comparable to that observed at sqrt(s)=20 GeV.
STAR observes a complex picture of RHIC collisions where correlation effects of different origins–initial state geometry, semi-hard scattering, hadronization, as well as final state interactions such ...as quantum intensity interference - coexist. Presenting the measurements of flow, mini-jet deformation, modified hadronization, and the Hanbury Brown and Twiss effect, we trace the history of the system from the initial to the final state. The resulting picture is discussed in the context of identifying the relevant degrees of freedom and the likely equilibration mechanism.
We propose an evolution of the Mu2e experiment, called Mu2e-II, that would leverage advances in detector technology and utilize the increased proton intensity provided by the Fermilab PIP-II upgrade ...to improve the sensitivity for neutrinoless muon-to-electron conversion by one order of magnitude beyond the Mu2e experiment, providing the deepest probe of charged lepton flavor violation in the foreseeable future. Mu2e-II will use as much of the Mu2e infrastructure as possible, providing, where required, improvements to the Mu2e apparatus to accommodate the increased beam intensity and cope with the accompanying increase in backgrounds.
PDF
