11,309 research outputs found
Energy Loss in Nuclear Drell-Yan Process
By means of the nuclear parton distributions which can be used to provide a
good explanation for the EMC effect in the whole x range, we investigate the
energy loss effect in nuclear Drell-Yan process. When the cross section of
lepton pair production is considered varying with the center-of-mass energy of
the nucleon-nucleon collision, we find that the nuclear Drell-Yan(DY) ratio is
suppressed due to the energy loss, which balances the overestimate of the DY
ratio only in consideration of the effect of nuclear parton distributions.Comment: 10 pages, LaTeX, 1 ps figures, To appear in Eur. Phys. J.
Spin Correlations in top quark pair production near threshold at the Linear Collider
We investigate the spin correlations in top quark pair production near
threshold at the linear collider. Comparing with the results above
the threshold region, we find that near the threshold region the off-diagonal
basis, the optimized decomposition of the top quark spins above the threshold
region, does not exist, and the beamline basis is the optimal basis, in which
there are the dominant spin components: the up-down (UD) component for scattering and the down-up (DU) component for scattering can
make up more than 50% of the total cross section, respectively.Comment: 12 pages, 3 figures, minor modification
Next-to-leading order QCD predictions for associated production of top squarks and charginos at the CERN LHC
We present the calculations of the complete next-to-leading order (NLO)
inclusive total cross sections for the associated production processes in the Minimal Supersymmetric Standard Model at
the CERN Large Hadron Collider. Our calculations show that the total cross
sections for the production for the lighter top
squark masses in the region 100 GeV 160 GeV can reach 1 pb
in the favorable parameter space allowed by the current precise experiments,
and in other cases the total cross sections generally vary from 10 fb to
several hundred fb except both 500 GeV and the
production channel. Moreover, we find that the
NLO QCD corrections in general enhance the leading order total cross sections
significantly, and vastly reduce the dependence of the total cross sections on
the renormalization/factorization scale, which leads to increased confidence in
predictions based on these results.Comment: 42 pages, 13 figures, RevTex4. Journal-ref adde
Transverse momentum resummation in soft-collinear effective theory
We present a universal formalism for transverse momentum resummation in the
view of soft-collinear effective theory (SCET), and establish the relation
between our SCET formula and the well known Collins-Soper-Sterman's pQCD
formula at the next-to-leading logarithmic order (NLLO). We also briefly
discuss the reformulation of joint resummation in SCET.Comment: 23 pages, 7 figures; version to appear in Phys. Rev.
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