Search results for "Cross Section"
showing 10 items of 3111 documents
Gauge fields, hidden local symmetries, and meson exchange currents
1997
Abstract The model dependence of the electromagnetic isovector meson exchange current (MEC) operator at higher momentums transfer is studied. For this purpose, the MEC operator constructed from a Lagrangian of the πϱa 1 system obtained within the framework of the hidden local symmetries (HLS) approach is compared with the analogous operator derived earlier from a minimal Yang-Mills (YM) Lagrangian. Numerical results for the deuteron disintegration near threshold show that the model dependent part of the exchange current modifies the tail of the cross section sensibly and that the presence of the a 1 meson both in the MEC and in the nuclear interaction provides a consistent description of th…
NNLO tau+tau- production cross section at threshold
2003
4 páginas, 3 figuras.-- Comunicación presentada a la 9ª High-Energy Physics International Conference on Quantum ChromoDynamics (QCD 02) celebrada del 2 al 9 de Julio de 2002 en Montpellier (Francia).-- arXiv:hep-ph/0210003v1
Measurements of the Hadronic Cross Section and of Meson Transition Form Factors at BESIII for an improved Standard Model Prediction of (g−2)μ
2015
Abstract The BESIII experiment at the Beijing tau-charm factory BEPCII recently has embarked on a series of form factor measurements with the goal to improve the hadronic vacuum polarization as well as the hadronic light-by-light contributions to ( g − 2 ) μ . The status of the flagship measurements and preliminary results are presented.
Next-to-next-to-leading order τ+τ- production cross section close to threshold
2001
13 páginas, 5 figuras.-- PACS number(s): 12.20.Ds, 14.60.Fg
Suppression of charged particle production at large transverse momentum in central Pb–Pb collisions at sNN=2.76 TeV
2011
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at root s(NN) = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in |eta| < 0.8 and 0.3 < p(T) < 20 GeV/c are compared to the expectation in pp collisions at the same root s(NN), scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor R-AA. The result indicates only weak medium effects (R-AA approximate to 0.7) in peripheral collisions. In cen…
Total and inelastic cross sections at LHC ats=7 TeVand beyond
2011
We discuss expectations for the total and inelastic cross sections at LHC CM energies $\sqrt{s}=7\text{ }\text{ }\mathrm{TeV}$ and 14 TeV obtained in an eikonal minijet model augmented by soft gluon ${k}_{t}$-resummation, which we describe in some detail. We present a band of predictions which encompass recent LHC data and suggest that the inelastic cross section described by two-channel eikonal models include only uncorrelated processes. We show that this interpretation of the model is supported by the LHC data.
Nuclear modification of forward J/ψ production in proton-nucleus collisions at the LHC
2016
We re-evaluate the nuclear suppression of forward J/ψ production at high energy in the Color Glass Condensate framework. We use the collinear approximation for the projectile proton probed at large x and an up to date dipole cross section fitted to HERA data to describe the target in proton-proton collisions. We show that using the Glauber approach to generalize the proton dipole cross section to the case of a nucleus target leads to a nuclear modification factor much closer to LHC data than previous estimates using the same framework.
Single inclusive particle production at high energy from HERA data to proton-nucleus collisions
2013
We study single inclusive hadron production in proton-proton and proton-nucleus collisions in the CGC framework. The parameters in the calculation are determined solely by standard nuclear geometry and by electron-proton deep inelastic scattering data, which is fit using the running coupling BK equation. We show that it is possible to obtain a good fit of the HERA inclusive cross section also without an anomalous dimension in the initial condition. We argue that one must consistently use the proton transverse area as measured by a high virtuality probe in DIS also for the single inclusive cross section in proton-proton and proton-nucleus collisions. We show that this leads to a midrapidity …
Measurement of the WW cross section in s=7 TeV pp collisions with the ATLAS detector and limits on anomalous gauge couplings
2012
This Letter reports a measurement of the W W production cross section in root s = 7 TeV pp collisions using data corresponding to an integrated luminosity of 1.02 fb(-1) collected with the ATLAS de ...
Measurement of the tt¯ production cross section using dilepton events in pp¯ collisions
2011
We present a measurement of the a production cross section sigma((u) over bar) in p (p) over bar collisions at root s = 1.96 TeV using 5.4 fb(-1) of integrated luminosity collected with the D0 detector. We consider final states with at least two jets and two leptons (ee, e mu, mu mu), and events with one jet for the e mu final state as well. The measured cross section is sigma((u) over bar) = 7.36(-0.79)(+0.90)(stat + syst) pb. This result combined with the cross section measurement in the lepton + jets final state yields sigma((u) over bar) = 7.56(-0.56)(+0.63)(stat + syst) pb, which agrees with the standard model expectation. The relative precision of 8% of this measurement is comparable …