562 research outputs found
Photon-jet correlations in and collisions
We compare results of the -factorization approach and the
next-to-leading order collinear-factorization approach for photon-jet
correlations in and collisions at RHIC and Tevatron energies.
We discuss correlations in the azimuthal angle as well as in the
two-dimensional space of transverse momentum of photon and jet. Different
unintegrated parton distributions (UPDF) are included in the
-factorization approach. The results depend on UPDFs used. The standard
collinear approach gives cross section comparable to the -factorization
approach. For correlations of the photon and any jet the NLO contributions
dominate at relatively small azimuthal angles as well as for asymmetric
transverse momenta. For correlations of the photon with the leading jet (the
one having the biggest transverse momentum) the NLO approach gives zero
contribution at which opens a possibility to study
higher-order terms and/or UPDFs in this region.Comment: 14 pages, 17 figure
Qubit flip game on a Heisenberg spin chain
We study a quantum version of a penny flip game played using control
parameters of the Hamiltonian in the Heisenberg model. Moreover, we extend this
game by introducing auxiliary spins which can be used to alter the behaviour of
the system. We show that a player aware of the complex structure of the system
used to implement the game can use this knowledge to gain higher mean payoff.Comment: 13 pages, 3 figures, 3 table
Unintegrated CCFM parton distributions and transverse momentum of gauge bosons
Transverse momentum distribution of gauge bosons and is
calculated using unintegrated parton distributions obtained by solving leading
order CCFM equation(s) in the impact parameter space. For illustration we
compare the results of the fixed-order collinear, soft-gluon resummation and
CCFM approaches. A parameter of a nonperturbative form factor is adjusted to
the D0 data. In contrast to the collinear approach, the leading order
calculation based on the unintegrated CCFM parton distributions generates
transverse momentum distributions of gauge bosons, which are almost consistent
with experimental data provided the parameter of the nonperturbative form
factor is appropriately adjusted. The - asymmetry is calculated as a
function of the boson rapidity and transverse momentum. Predictions are given
for RHIC and LHC.Comment: 19 pages, 8 figure
Noise Effects in Quantum Magic Squares Game
In the article we analyse how noisiness of quantum channels can influence the
magic squares quantum pseudo-telepathy game. We show that the probability of
success can be used to determine characteristics of quantum channels. Therefore
the game deserves more careful study aiming at its implementation.Comment: 5 figure
Unintegrated gluon distributions and Higgs boson production in proton-proton collisions
Inclusive cross sections for Higgs boson production in proton-proton
collisions are calculated in the formalism of unintegrated gluon distributions
(UGDF). Different UGDF from the literature are used. Although they were
constructed in order to describe the HERA deep-inelastic scattering data,
they lead to surprisingly different results for Higgs production. We present
both two-dimensional invariant cross section as a function of Higgs rapidity
and transverse momentum, as well as corresponding projections on rapidity or
transverse momentum. We quantify the differences between different UGD's by
applying different cuts on interrelations between transverse momentum of Higgs
and transverse momenta of both fusing gluons. We focus on large rapidity
region. The interplay of the gluon-gluon fusion and weak-boson fusion in
rapidity and transverse momentum is discussed. We find that above
50-100 GeV the weak-gauge-boson fusion dominates over gluon-gluon fusion.Comment: 32 pages, 18 figures, corrected version, restructured, misprints
removed, discussion added, new figure added, in print in EPJ
Pion and Kaon Production in Nucleon - Nucleon Collisions
Inclusive cross section for pion production in proton - proton collisions are
calculated based on unintegrated parton distribution functions (uPDFs). In
addition to purely gluonic terms the present approach includes also quark
degrees of freedom. Phenomenological fragmentation functions from the
literature are used. The new mechanisms are responsible for -
asymmetry. In contrast to standard collinear approach, application of 2 1
- factorization approach can be extended towards much lower transverse
momenta, both at mid and forward rapidity region. The results of the
calculation are compared with SPS and RHIC data.Comment: a talk presented by Marta Tichoruk at the international conference
MESON2006, Cracow, June 2006, 5 pages, 3 figure
Noisy quantum Monty Hall game
The influence of spontaneous emission channel and generalized Pauli channel
on quantum Monty Hall Game is analysed. The scheme of Flittney and Abbott is
reformulated using the formalism of density matrices. Optimal classical
strategies for given quantum strategies are found. The whole presented scheme
illustrates how quantum noise may change the odds of a zero-sum game.Comment: 10 pages, 3 figure
Unintegrated parton distributions and pion production in collisions at SPS and RHIC energies
Inclusive cross sections for pion production in collisions are
calculated for the first time fully based on unintegrated gluon, quark and
antiquark distributions (uPDF). We use recently developed Kwieci\'nski uPDF's
and different phenomenological fragmentation functions (FF) from the
literature. In addition to the diagram we include also
and diagrams for inclusive parton production. The cross section for
pions is obtained then by convoluting the inclusive parton distributions and
FFs. Applications for SPS and RHIC are shown.Comment: 4 pages, 3 figures, a talk presented at the Quark Matter 2005
conference, Budapest, August 200
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