1,706 research outputs found
New Structure Function Results at Low x and High Q^2 from HERA
A precise proton structure function F_2 at low x is measured. The data is
interpreted in the framework of QCD with an extraction of gluon density xg. The
charm contribution to F_2 is determined in an extended kinematic range. Neutral
and charged current cross-sections at high Q^2 are also measured and compared
with the Standard Model predictions.Comment: 8 pages, 6 figure
Review of Recent Calculations of the Hadronic Vacuum Polarisation Contribution
Recent calculations of the hadronic vacuum polarisation contribution are
reviewed. The focus is put on the leading-order contribution to the muon
magnetic anomaly involving annihilation cross section data as input to
a dispersion relation approach. Alternative calculation including tau data is
also discussed. The data are corrected for various isospin-breaking
sources which are explicitly shown source by source.Comment: 8 pages, 9 figures, 3 tables, invited talk given at the FCCP 2015
worksho
HERA Inclusive Neutral and Charged Current Cross Sections and a New PDF Fit, HERAPDF 2.0
In this talk, I present the brand new results from the H1 and ZEUS
Collaborations on the combination of all previously published inclusive deep
inelastic cross sections at HERA for neutral and charged current
scattering for zero beam polarisation and the corresponding parton
distributions functions, HERAPDF 2.0, at up to next-to-next-to-leading order
(NNLO). The results also include a new precise determination at next-to-leading
order (NLO) of the strong coupling constant
(excluding scale uncertainties) based on a simultaneous fit to the combined
inclusive cross section data and jet production data.Comment: 6 pages, 2 figures, talk given at the EDS Blois 2015 Conference for
the H1 and ZEUS Collaboration
Experimental implications for a linear collider of SUSY dark matter scenario
This talk presents the detection issues for the lightest slepton
\tilde{\tau}_1 at a future e+e- TeV collider given the dark matter constraints
set on the SUSY mass spectrum by the WMAP results. Two methods for measuring
its mass m_{\tilde{\tau}_1} and the resulting precision on the dark matter
density are briefly discussed in the SUSY mSUGRA scenario with R-parity
conservation when the mass difference between m_{\tilde{\tau}_1} and that of
the lightest neutralino is small (a few GeV). The analysis is performed with
TESLA parameters in both head-on and crossing angle modes.Comment: Talk given at the International Conference on Linear Colliders -
Paris, France, April 19-23, 200
New Analysis of SUSY Dark Matter Scenarios at ILC
Applying realistic veto efficiencies for the low angle electromagnetic
calorimeter located in the very forward direction of the future international
linear collider, we revisited the Standard Model background contributions
studied previously in stau analyses with supersymmetrical dark matter
scenarios
Study of Rare Exclusive Electroweak Processes at HERA
Results on multi-lepton events at high transverse momenta, isolated lepton
events with large missing transverse energy and single W production reported to
this conference are based for the first time on the full data samples taken by
two colliding experiments, H1 and ZEUS, at HERA. The data correspond to an
integrated luminosity of about 1fb-1 from both experiments.Comment: Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 4 pages,
LaTeX, 4 ps figure
Top and EW Physics at the LHeC
The LHeC is a proposed upgrade of the LHC to study collisions in the
TeV regime, by adding a 60 GeV electron beam through an energy recovery linac.
In , high precision top and electroweak physics can be performed, such as
measurements of anomalous top couplings, light quark couplings to the boson
and the energy dependence of the weak mixing angle , for
which simulation studies are presented.Comment: 6 pages, 3 figures, 1 table, talk given at the EPS-HEP 2015
conference for the LHeC Study Grou
Electron polarization measurement using a Fabry-Perot cavity at HERA
A new Compton longitudinal polarimeter currently under construction for HERA
is presented. The key component of the polarimeter is a Fabry-Perot cavity
located around the electron beam pipe. With such an optical cavity, a
continuous laser power equivalent to 5 kW, much higher than those commercially
available, can be achieved, leading to one backscattered photon per bunch
crossing. This ``few-photon mode'' will allow a very precise determination of
the calorimeter response with little systematic uncertainty. The electron
polarization measurement at the per mill level is expected.Comment: Talk given at the International Europhysics Conference on High Energy
Physics, Budapest (Hungary), July 12-18, 2001. On behalf of E. Barrelet, V.
Brisson, M. Jacquet-Lemire, A. Reboux, C. Pascaud, F. Zomer and the HERA
POL2000 grou
Review of recent leading-order hadronic vacuum polarization calculation
The leading-order hadronic contribution to the muon magnetic moment anomaly
, calculated using a dispersion integral of
annihilation data and data, is briefly reviewed. This contribution has
the largest uncertainty to the predicted value of , which differs from
the direct measurement by standard deviations for the based analysis. Recent results and main open issues on the subject are
discussed.Comment: 10 pages, 6 figures, Proceedings of Photon 2013. arXiv admin note:
text overlap with arXiv:1302.189
Searches for Leptoquarks, Squarks in SUSY and Excited Fermions at HERA
Various searches for leptoquarks, scalar quarks in -violating
supersymmetric models, and excited fermions performed by the HERA experiments
H1 and ZEUS are reviewed. No evidence for new particle production was observed
from data collected by both experiments since 1994 in either electron-proton
and positron-proton collisions. Stringent limits derived on the masses and
couplings of these new particles are compared whenever appropriate with those
from LEP, the Tevatron and low energy experiments.Comment: 5 pages, 2 figure
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