5,151 research outputs found
Mixing and CP Violation at the Tevatron
Measurements of meson mixing and CP violation parameters obtained by the CDF
and D0 experiments at the Fermilab Tevatron are presented. These include
results on and meson mixing, and searches for CP violation in the
decay , in mixing through semileptonic meson decays,
and in the interference between mixing and decay in the process .Comment: 9 pages, Proceedings of the Hadron Collider Physics Symposium
(HCP2008),Galena, Illinois, US
Top Quark Mass Measurements at the Tevatron
The general strategy, as well as channel-specific details, applied to the
measurement of the top quark mass at the Tevatron in Run I are reviewed, and
the combination of the results obtained by the CDF and DO collaborations
presented. The accelerator and detector upgrades for Run II are described, and
expected improvements in the systematic uncertainties on the measurement
evaluated.Comment: Latex (Frascati.sty), 11 pages, 3 figs. Talk given at the 14th
Rencontres de Physique de la Vallee d'Aoste, La Thuile, Aosta Valley, Italy,
February 200
Determination of Scanning Efficiencies in Experiments Using Nuclear Emulsion Sheets
During their exposure, nuclear emulsion sheets detect both tracks from
experiment-related particles, as well as a considerable amount of background
tracks, mainly due to cosmic rays. Unless the exposure has been fairly short,
it is therefore fairly likely that a fraction of the tracks that have been
identified as belonging to the particles the experiment is interested in, are
really due to background. A method, which allows to measure this fraction
reliably directly from the data, is described.Comment: 7 pages, uses elsart, to be published in NIMA 450, p 44
High pT Hadronic Top Quark Identification
At the LHC objects with masses at the electroweak scale will for the first time be produced with very large transverse momenta. In many cases, these objects decay hadronically, producing a set of collimated jets. This interesting new experimental phenomenology requires the development and tuning of new tools, since the usual reconstruction methods would simply reconstruct a single jet. This note describes the application of the YSplitter algorithm in conjunction with the jet mass to identify high transverse momentum top quarks decaying hadronically
A Supersymmetric Solution to the Solar and Atmospheric Neutrino Anomalies
The formalism for neutrino flavor change induced by lepton family number
violating interactions is developed for the three-neutrino case, and used to
derive the corresponding flavor change probabilities in matter. Applied to the
solar and atmospheric neutrino fluxes, it is argued that the observed
anomalies, including the zenith dependence for the atmospheric case, could be
due to such interactions.Comment: 6 pages, 1 figure Modifications: include limit from tau -> rho mu
(leads to somewhat different conclusions) and a change to the figur
After the Standard Model: New Resonances at the LHC
Experiments will soon start taking data at CERN's Large Hadron Collider (LHC)
with high expectations for discovery of new physics phenomena. Indeed, the
LHC's unprecedented center-of-mass energy will allow the experiments to probe
an energy regime where the standard model is known to break down. In this
article, the experiments' capability to observe new resonances in various
channels is reviewed.Comment: Preprint version of a Brief Review for Modern Physics Letters A.
Changes w.r.t. the fully corrected version are smal
General bounds on non-standard neutrino interactions
We derive model-independent bounds on production and detection non-standard
neutrino interactions (NSI). We find that the constraints for NSI parameters
are around O(10^{-2}) to O(10^{-1}). Furthermore, we review and update the
constraints on matter NSI. We conclude that the bounds on production and
detection NSI are generally one order of magnitude stronger than their matter
counterparts.Comment: 18 pages, revtex4, 1 axodraw figure. Minor changes, matches published
versio
Loop bounds on non-standard neutrino interactions
We reconsider the bounds on non-standard neutrino interactions with matter
which can be derived by constraining the four-charged-lepton operators induced
at the loop level. We find that these bounds are model dependent. Naturalness
arguments can lead to much stronger constraints than those presented in
previous studies, while no completely model-independent bounds can be derived.
We will illustrate how large loop-contributions to four-charged-lepton
operators are induced within a particular model that realizes gauge invariant
non-standard interactions and discuss conditions to avoid these bounds. These
considerations mainly affect the constraint on the
non-standard coupling strength \eps_{e\mu}, which is lost. The only
model-independent constraints that can be derived are .
However, significant cancellations are required in order to saturate this
bound.Comment: Minor changes, version to be published in JHEP. 17 pages, 3 Axodraw
figures, REVTeX
- …