6,312 research outputs found
Studies of Fragmentation and Colour Reconnection at LEP
Hadronic events at the Z pole have been investigated in search for Colour
Reconnection effects and QCD coherence. Colour Reconnection effects are
searched for in three-jet events and the data results are compared to the
predictions of different Monte Carlo models. QCD colour coherence effects are
tested through the multiplicity distributions of hadrons with restricted
momenta, and the LEP1 e+e- data is compared to HERA e+p data under the
equivalence assumption of the e+e- hemisphere with the current region of the
Breit frame of reference.Comment: 4 pages, 4 figures, contribution to ICHEP06 proceeding
Four-fermion final states in e+e- collisions at LEP2
The measurements of four-fermion production rates performed at LEP2 in e+e-
collisions at centre-of-mass energies ranging from 161 to 209 GeV are
presented. The focus is put on processes that involve the production and decay
of W or Z electroweak bosons. Results on W decay rates and couplings are also
discussed.Comment: 5 pages, 3 figures. To appear in the Proceedings of 'XIV IFAE -
Incontri sulla Fisica delle Alte Energie', 3-5 April 2002, Parm
Gauge Boson Self Couplings and four fermion final states at LEP
Four-fermion productions measured in the LEP2 data are reviewed. The total
and differential cross-section yields represent the first clear evidence for
the existence of gauge boson self couplings, in support of the non-abelian
SU(2)xU(1) structure of the electroweak model, at the percent level.Comment: 4 pages, 3 figures. To appear in the Proceedings of 'XV IFAE -
Incontri sulla Fisica delle Alte Energie', 23-26 April 2003, Lecce, Ital
Measurements of the properties of the Higgs-like boson with the CMS experiment at the LHC
Measurements of the properties of the recently discovered Higgs-like boson are presented using data samples recorded by the CMS experiment corresponding to integrated luminosities of up to 5.1 fb−1 at 7TeV and up to 12.2 fb−1
at 8TeV in proton proton collisions at the LHC. The results combine decay modes in pairs of photons, Z bosons, W bosons, tau leptons and b quarks. The mass of the boson is determined to be 125.8 ± 0.4 (stat.) ± 0.4 (syst.)GeV, and the signal strength at the measured mass is μ = 0.88 ± 0.21, normalized to the standard model expectation. Combined results on couplings, spin and parity reveal a broad agreement with the expectations of a standard model Higgs boson
First observation and measurement of the resonant structure of the lambda_b->lambda_c pi-pi+pi- decay mode
We present the first observation of the lambda_b->lambda_c pi-pi+pi- decay
using data from an integrated luminosity of approximately 2.4 fb-1 of ppbar
collisions at ECM=1.96 TeV, collected with the CDF II detector at the Fermilab
Tevatron. We also present the first observation of the resonant decays
lambda_b->sigma_c(2455)0 pi+pi- ->lambda_c pi-pi+pi-, lambda_b->sigma_c(2455)++
pi-pi- ->lambda_c pi-pi+pi-, lambda_b->lambda_c(2595)+ pi- ->lambda_c pi-pi+pi-
and lambda_b->lambda_c(2625)+ pi- ->lambda_c pi-pi+pi-, and measure their
relative branching ratios.Comment: 3 pages, 3 figures, to appear in the proceedings of LEPTON PHOTON
2009, Hamburg, German
Physics Behind Precision
This document provides a writeup of contributions to the FCC-ee mini-workshop
on "Physics behind precision" held at CERN, on 2-3 February 2016.Comment: https://indico.cern.ch/event/469561
H(+),K(+)-atpase (proton pump) is the target autoantigen of Th1-type cytotoxic T cells in autoimmune gastritis.
Molecular Mimicry between Helicobacter pylori Antigens and H+,K+–Adenosine Triphosphatase in Human Gastric Autoimmunity
Autoimmune gastritis and Helicobacter pylori–associated gastric atrophy develop through similar mechanisms involving the proton pump H+,K+–adenosine triphosphatase as autoantigen. Here, we report that H. pylori–infected patients with gastric autoimmunity harbor in vivo–activated gastric CD4+ T cells that recognize both H+,K+–adenosine triphosphatase and H. pylori antigens. We characterized the submolecular specificity of such gastric T cells and identified cross-reactive epitopes from nine H. pylori proteins. Cross-reactive H. pylori peptides induced T cell proliferation and expression of T helper type 1 functions. We suggest that in genetically susceptible individuals, H. pylori infection can activate cross-reactive gastric T cells leading to gastric autoimmunity via molecular mimicry
Search for CP Violation in the Decay Z -> b (b bar) g
About three million hadronic decays of the Z collected by ALEPH in the years
1991-1994 are used to search for anomalous CP violation beyond the Standard
Model in the decay Z -> b \bar{b} g. The study is performed by analyzing
angular correlations between the two quarks and the gluon in three-jet events
and by measuring the differential two-jet rate. No signal of CP violation is
found. For the combinations of anomalous CP violating couplings, and , limits of \hat{h}_b < 0.59h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st
Dark matter searches at LHC
Besides Standard Model measurements and other Beyond Standard Model studies,
the ATLAS and CMS experiments at the LHC will search for Supersymmetry, one of
the most attractive explanation for dark matter. The SUSY discovery potential
with early data is presented here together with some first results obtained
with 2010 collision data at 7 TeV. Emphasis is placed on measurements and
parameter determination that can be performed to disentangle the possible SUSY
models and SUSY look-alike and the interpretation of a possible positive
supersymmetric signal as an explanation of dark matter.Comment: 15 pages, 14 figures, Invited plenary talk given at DISCRETE 2010:
Symposium On Prospects In The Physics Of Discrete Symmetries, 6-11 Dec 2010,
Rome, Ital
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