77 research outputs found
Exclusive Production at the LHC with Forward Proton Tagging
A process of Central Exclusive production in proton-proton
collisions and its theoretical description is presented. A possibility of its
measurement, during the special low luminosity LHC runs, with the help of the
ATLAS central detector for measuring pions and the ALFA stations for tagging
the scattered protons is studied. A visible cross section is estimated to be 21
b for TeV, which gives over 2000 events for 100 b
of integrated luminosity. Differential distributions in pion pseudorapidities,
pion and proton transverse momenta as well as invariant mass are
shown and discussed.Comment: 9 pages, 7 figure
Measurement of exclusive production of scalar meson in proton-(anti)proton collisions via decay
We consider a measurement of exclusive production of scalar
meson in the proton-proton collisions at LHC and RHIC and in
the proton-antiproton collisions at the Tevatron via decay. The corresponding amplitude for exclusive
double-diffractive meson production was obtained within the
-factorization approach including virtualities of active gluons and the
corresponding cross section is calculated with unintegrated gluon distribution
functions (UGDFs) known from the literature. The four-body reaction constitutes an irreducible background to the exclusive
meson production. We calculate several differential distributions
for process including absorptive
corrections. The influence of kinematical cuts on the signal-to-background
ratio is investigated. Corresponding experimental consequences are discussed.Comment: 16 pages, 10 figures, 2 table
reaction at high energies
We evaluate differential distributions for the four-body reaction at high energies which constitutes an irreducible background to
three-body processes , where , ,
, , . We consider central diffractive
contribution mediated by Pomeron and Reggeon exchanges as well as completely
new mechanism of emission of kaons from the proton lines. We include absorption
effects due to proton-proton interaction and kaon-kaon rescattering. We compare
our results with measured cross sections for the CERN ISR experiment. We make
predictions for future experiments at RHIC, Tevatron and LHC. Differential
distributions in invariant two-kaon mass, kaon rapidities and transverse
momenta of kaons are presented. Two-dimensional distribution in is particularly interesting. The higher the incident energy, the
higher preference for the same-hemisphere emission of kaons. We find that the
kaons from the new mechanism of emission directly from proton lines are
produced rather forward and backward but the corresponding cross section is
rather small. The processes considered here constitute a sizeable contribution
to the total proton-proton cross section as well as to kaon inclusive cross
section.
We consider a measurement of exclusive production of scalar meson
in the proton-proton collisions via decay. The
corresponding amplitude for exclusive central diffractive meson
production is calculated within the -factorization approach. The
influence of kinematical cuts on the signal-to-background ratio is discussed.Comment: 20 pages, 16 figures. text has been corrected and supplemented, cross
section for forward/backward mechanisms has been corrected. arXiv admin note:
substantial text overlap with arXiv:1103.564
Exclusive meson pair production in proton-proton collisions
We present a study of the exclusive production of meson pairs in the
four-body , reactions at high
energies which constitute an irreducible background to resonance states (e.g.
, , , , ). We consider
central diffractive contribution mediated by Pomeron and Reggeon exchanges and
new diffractive mechanism of emission of pions/kaons from the proton lines. We
include absorption effects due to proton-proton interaction and pion/kaon
rescattering. Predictions for the total cross section and differential
distributions in pion/kaon rapidity and transverse momentum as well as
two-pion/kaon invariant mass are presented for the RHIC, Tevatron and LHC
colliders. Finally we consider a measurement of exclusive production of a
scalar meson via ,
decay.Comment: 4 pp., 4 figures, talk presented by PL at MESON2012 - 12th
International Workshop on Meson Production, Properties and Interaction,
Krakow, Poland, 31 May - 5 June 201
Exclusive reaction at LHC and RHIC
We evaluate differential distributions for the four-body reaction. The amplitude for the process is calculated in the Regge
approach including many diagrams. We make predictions for possible future
experiments at RHIC and LHC energies. Very large cross sections are found which
is partially due to interference of a few mechanisms. Presence of several
interfering mechanisms precludes extraction of the elastic
scattering cross section. Absorption effects are estimated. Differential
distributions in pseudorapidity, rapidity, invariant two-pion mass,
transverse-momentum and energy distributions of neutrons are presented for
proton-proton collisions at = 500 GeV (RHIC) and = 0.9,
2.36 and 7 TeV (LHC). Cross sections with experimental cuts are presented.Comment: 22 pages, 18 figures, calculations have been corrected, new processes
added, discussion expanded in print in Phys. Rev.
Modeling pion and proton total cross-sections at LHC
To settle the question whether the growth with energy is universal for
different hadronic total cross-sections, we present results from theoretical
models for pion-proton, proton-proton and proton-antiproton total
cross-sections. We show that present and planned experiments at LHC can
differentiate between different models, all of which are consistent with
presently available (lower energy) data. This study is also relevant for the
analysis of those very high energy cosmic ray data which require reliable
pion-proton total cross-sections as seeds. A preliminary study of the total
pion-pion cross-sections is also made.Comment: 18 pages, 5 figures, submitted to Physics Letters
Exclusive double-diffractive production of open charm in proton-proton and proton-antiproton collisions
We calculate differential cross sections for exclusive double diffractive
(EDD) production of open charm in proton-proton and proton-antiproton
collisions. Sizeable cross sections are found. The EDD contribution constitutes
about 1 % of the total inclusive cross section for open charm production. A few
differential distributions are shown and discussed. The EDD contribution falls
faster both with transverse momentum of the quark/antiquark and the invariant mass than in the inclusive case.Comment: 11 pages, 7 figure
Low-energy pion-pion scattering in the and reactions
We evaluate the contribution of pion-pion rescattering to the and reactions. We compare our
results with the close-to-threshold experimental data. The pion-pion
rescattering contribution is found there to be negligible. The predictions for
future experiments with PANDA detector at High Energy Storage Ring (HESR) in
GSI Darmstadt are presented. It is discussed how to cut off the dominant Roper
resonance and double- excitation mechanisms leading to the channel in final state. Differential distributions in momentum
transfers, transverse momentum, effective two-pions mass, relative azimuthal
angle between pions, and pion rapidities are presented.Comment: 14 pages, 11 figure
Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR
The possibility of measuring the proton electromagnetic form factors in the
time-like region at FAIR with the \PANDA detector is discussed. Detailed
simulations on signal efficiency for the annihilation of into a
lepton pair as well as for the most important background channels have been
performed. It is shown that precision measurements of the differential cross
section of the reaction can be obtained in a wide
angular and kinematical range. The individual determination of the moduli of
the electric and magnetic proton form factors will be possible up to a value of
momentum transfer squared of (GeV/c). The total cross section will be measured up to (GeV/c).
The results obtained from simulated events are compared to the existing data.
Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations,
4 tables, 9 figure
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
Simulation results for future measurements of electromagnetic proton form
factors at \PANDA (FAIR) within the PandaRoot software framework are reported.
The statistical precision with which the proton form factors can be determined
is estimated. The signal channel is studied on the basis
of two different but consistent procedures. The suppression of the main
background channel, , is studied.
Furthermore, the background versus signal efficiency, statistical and
systematical uncertainties on the extracted proton form factors are evaluated
using two different procedures. The results are consistent with those of a
previous simulation study using an older, simplified framework. However, a
slightly better precision is achieved in the PandaRoot study in a large range
of momentum transfer, assuming the nominal beam conditions and detector
performance
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