43 research outputs found
Charm production nearby threshold in pA-interactions at 70 GeV
The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP,
Protvino) are presented. Interactions of the 70 GeV proton beam with C, Si and
Pb targets were studied to detect decays of charmed , ,
, mesons and baryon near their production threshold.
Measurements of lifetimes and masses are shown a good agreement with PDG data.
The inclusive cross sections of charm production and their A-dependencies were
obtained. The yields of these particles are compared with the theoretical
predictions and the data of other experiments. The measured cross section of
the total open charm production ( = 7.1
2.3(stat) 1.4(syst) b/nucleon) at the collision c.m. energy
= 11.8 GeV is well above the QCD model predictions. The
contributions of different species of charmed particles to the total cross
section of the open charm production in proton-nucleus interactions vary with
energy.Comment: 4 pages, 6 pages, 38th International Conference on High Energy
Physics 3-10 August 2016, Chicago, US
Properties of Neutral Charmed Mesons in Proton--Nucleus Interactions at 70 GeV
The results of treatment of data obtained in the SERP-E-184experiment
"Investigation of mechanisms of the production of charmed particles in
proton-nucleus interactions at 70 GeV and their decays" by irradiating the
active target of the SVD-2 facility consisting of carbon, silicon, and lead
plates, are presented. After separating a signal from the two-particle decay of
neutral charmed mesons and estimating the cross section for charm production at
a threshold energy {\sigma}(c\v{c})=7.1 \pm 2.4(stat.) \pm 1.4(syst.)
\mub/nucleon, some properties of D mesons are investigated. These include the
dependence of the cross section on the target mass number (its A dependence);
the behavior of the differential cross sections d{\sigma}/dpt2 and
d{\sigma}/dxF; and the dependence of the parameter {\alpha} on the kinematical
variables xF, pt2, and plab. The experimental results in question are compared
with predictions obtained on the basis of the FRITIOF7.02 code.Comment: 9 pages, 9 figures,3 table
Observation of narrow baryon resonance decaying into in pA-interactions at with SVD-2 setup
SVD-2 experiment data have been analyzed to search for an exotic baryon
state, the -baryon, in a decay mode at on IHEP
accelerator. The reaction with a limited multiplicity was
used in the analysis. The invariant mass spectrum shows a resonant
structure with and . The statistical significance of this peak was estimated to be of . The mass and width of the resonance is compatible with the recently
reported - baryon with positive strangeness which was predicted as an
exotic pentaquark () baryon state. The total cross section for
production in pN-interactions for was estimated to be
and no essential deviation from A-dependence for inelastic
events was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some
references added, minor typos correcte
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal