35 research outputs found
Reconciling open charm production at the Fermilab Tevatron with QCD
We study the inclusive hadrodroduction of D^0, D^+, D^{*+}, and D_s^+ mesons
at next-to-leading order in the parton model of quantum chromodynamics endowed
with universal non-perturbative fragmentation functions (FFs) fitted to e^+e^-
annihilation data from CERN LEP1. Working in the general-mass
variable-flavor-number scheme, we resum the large logarithms through the
evolution of the FFs and, at the same time, retain the full dependence on the
charm-quark mass without additional theoretical assumptions. In this way, the
cross section distributions in transverse momentum recently measured by the CDF
Collaboration in run II at the Fermilab Tevatron are described within errors.Comment: 9 pages, 8 figure
Inclusive B-Meson Production at the LHC in the GM-VFN Scheme
We calculate the next-to-leading-order cross section for the inclusive
production of B mesons in pp collisions in the general-mass
variable-flavor-number scheme, an approach which takes into account the finite
mass of the b quarks. We use realistic evolved non-perturbative fragmentation
functions obtained from fits to e+e- data and compare results for the
transverse-momentum and rapidity distributions at a center-of-mass energy of 7
TeV with recent data from the CMS Collaboration. We find good agreement, in
particular at large values of pT.Comment: Minor changes to the text, accepted for publication in Phys. Rev.
About possible contribution of intrinsic charm component to inclusive spectra of charmed mesons
We calculate differential energy spectra (-distributions) of charmed
particles produced in proton-nucleus collisions, assuming the existence of
intrinsic heavy quark components in the proton wave function. For the
calculation, the recently proposed factorization scheme is used, based on the
Color Glass Condensate theory and specially suited for predictions of a
production of particles with large rapidities. It is argued that the intrinsic
charm component can, if it exists, dominate in a sum of two components,
intrinsic + extrinsic, of the inclusive spectrum of charmed particles produced
in proton-nucleus collisions at high energies, in the region of medium ,
, and can give noticeable contribution to atmospheric fluxes
of prompt muons and neutrinos.Comment: 10 pages, 4 figures. Version published in J. Phys. G
Collinear Subtractions in Hadroproduction of Heavy Quarks
We present a detailed discussion of the collinear subtraction terms needed to
establish a massive variable-flavour-number scheme for the one-particle
inclusive production of heavy quarks in hadronic collisions. The subtraction
terms are computed by convoluting appropriate partonic cross sections with
perturbative parton distribution and fragmentation functions relying on the
method of mass factorization. We find (with one minor exception) complete
agreement with the subtraction terms obtained in a previous publication by
comparing the zero-mass limit of a fixed-order calculation with the genuine
massles results in the MSbar scheme. This presentation will be useful for
extending the massive variable-flavour-number scheme to other processes.Comment: 29 pages, 17 figures include
Field ecology of Hunterellus hookeri (Hymenoptera: Encyrtidae), and population dynamics of its host, Ixodes scapularis (Acari: Ixodidae) in southeastern Massachusetts.
We present predictions for the inclusive production of charmed hadrons at the
CERN LHC in the general-mass variable-flavor-number scheme at next-to-leading
order. Detailed numerical results are compared to data where available, or
presented in a way to ease future comparisons with experimental results. We
also point out that measurements at large rapidity have the potential to pin
down models of intrinsic charm.Comment: 17 page
Inclusive production in p anti-p collisions with massive charm quarks
We calculate the next-to-leading order cross section for the inclusive production of D^{*+-} mesons in p p-bar collisions as a function of the transverse momentum and the rapidity in two approaches using massive or massless charm quarks. For the inclusive cross section, we derive the massless limit from the massive theory. We find that this limit differs from the genuine massless version with MS-bar factorization by finite corrections. By adjusting subtraction terms, we establish a massive theory with MS-bar subtraction which approaches the massless theory with increasing transverse momentum. With these results and including the contributions due to the charm and anti-charm content of the proton and anti-proton, we calculate the inclusive D^{*+-} cross section in p p-bar collisions using realistic evolved non-perturbative fragmentation functions and compare with recent data from the CDF Collaboration at the Fermilab Tevatron at center-of-mass energy root(S) = 1.96 TeV. We find reasonable, though not perfect, agreement with the measured cross sections
Inclusive Charmed-Meson Production at the CERN LHC
17 pagesWe present predictions for the inclusive production of charmed hadrons at the CERN LHC in the general-mass variable-flavor-number scheme at next-to-leading order. Detailed numerical results are compared to data where available, or presented in a way to ease future comparisons with experimental results. We also point out that measurements at large rapidity have the potential to pin down models of intrinsic charm