109 research outputs found
QCD Tests in Proton-Antiproton Collisions
We review the status of QCD tests in high energy p-pbar collisions. Contents:
i) Introduction ii) QCD in Hadronic Collisions iii) Jet Production iv) Heavy
Flavour Production v) W and Z Production vi) Direct Photons.Comment: 30 pages + 26 figs (available upon request), IFUP-TH 4/93,
Fermilab-PUB-93/19-E, to appear in Annual Review of Nuclear and Particle
Science, vol 4
Systematics of Heavy Quark Production at HERA
We discuss heavy quark and quarkonium production in various kinematic regions
at the HERA ep collider. In contrast to fixed target experiments, collider
kinematics allows the possibility of detailed measurements of particle
production in the proton fragmentation region. One thus can study parton
correlations in the proton Fock states materialized by the virtual photon
probe. We discuss various configurations of inelastic electron-proton
scattering, including peripheral, diffractive, and deep inelastic processes. In
particular, we show that intrinsic heavy quark Fock states can be identified by
the observation of quarkonium production at large and a low mean
transverse momentum which is insensitive to the virtuality of the photon.Comment: 17 pages, postscript. To obtain a copy of this paper send e-mail to
[email protected]
SUSY-Induced Top Quark FCNC Processes at Linear Colliders
In the Minimal Supersymmetric Model (MSSM) the hitherto unconstrained flavor
mixing between top-squark and charm-squark will induce the flavor-changing
neutral-current (FCNC) interaction between top quark and charm quark, which
then give rise to various processes at the next generation linear collider
(NLC), i.e., the top-charm associated productions via ,
and collisions as well as the top quark rare decays
(, or ). All these processes involve the same part of the
parameter space of the MSSM. Through a comparative analysis for all these
processes at the NLC, we found the best channel to probe such SUSY-induced top
quark FCNC is the top-charm associated production in collision,
which occurs at a much higher rate than or collision and
may reach the detectable level for some part of the parameter space. Since the
rates predicted by the Standard Model are far below the detectable level, the
observation of such FCNC events would be a robust indirect evidence of SUSY.Comment: 12 pages, 8 figures (more refs added, discussions extended
A novel measurement of and lifetimes using semileptonic decays at LHCb
I report new, world-leading LHCb results on heavy meson lifetimes. We use a
novel approach that suppresses the shortcomings typically associated with
reconstruction of semileptonic decays, allowing for precise measurements of
lifetimes and other properties in collider experiments. We achieve a 15% and a
improvement over current best determinations of the flavor-specific
lifetime and lifetime, respectively.Comment: 12 pages, 6 figures. Talk presented at the APS Division of Particles
and Fields Meeting (DPF 2017), July 31-August 4, 2017, Fermilab. C17073
A novel measurement of and lifetimes using semileptonic decays at LHCb
I report new, world-leading LHCb results on heavy meson lifetimes. We use a
novel approach that suppresses the shortcomings typically associated with
reconstruction of semileptonic decays, allowing for precise measurements of
lifetimes and other properties in collider experiments. We achieve a 15% and a
improvement over current best determinations of the flavor-specific
lifetime and lifetime, respectively.Comment: 12 pages, 6 figures. Talk presented at the APS Division of Particles
and Fields Meeting (DPF 2017), July 31-August 4, 2017, Fermilab. C17073
STAR Barrel Electromagnetic Calorimeter Absolute Calibration Using "Minimum Ionizing Particles" from Collisions at RHIC
The procedure for the STAR Barrel Electromagnetic Calorimeter (BEMC) absolute
calibrations, using penetrating charged particle hits (MIP-hits) from physics
events at RHIC, is presented. Its systematic and statistical errors are
evaluated. It is shown that, using this technique, the equalization and
transfer of the absolute scale from the test beam can be done to a percent
level accuracy in a reasonable amount of time for the entire STAR BEMC.
MIP-hits would also be an effective tool for continuously monitoring the
variations of the BEMC tower's gains, virtually without interference to STAR's
main physics program. The method does not rely on simulations for anything
other than geometric and some other small corrections, and also for estimations
of the systematic errors. It directly transfers measured test beam responses to
operations at RHIC.Comment: 19 pages, 7 figures, Accepted to NIM-
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