According to modern theories, the parameters of neutral mesons such as their mass and width are closely connected with the medium in which the mesons are present. Experimental data on the study of ...mesons in a nuclear medium are in demand for development of theoretical models describing processes in the field of nonperturbative quantum chromodynamics (QCD). Masses and widths of neutral mesons produced in meson-nucleus interactions on various nuclei are measured in the Hyperon-M experiment at the U70 accelerator. The paper describes a method for precision measurement of the parameters of neutral mesons, presents the results on measurement of the mass and width of the
meson and preliminary results on the measurement of the mass and width of the
meson. The measurements indicate the absence of dependence of the quantities under study on the nuclear environment.
Studies at the Nuclotron in JINR indicate the presence of a previously unknown resonance-like structure in the two-photon mass spectrum in the region of 300–400 MeV/
c
2
, observed in nucleus–nucleus ...interactions. The goal of this work is to search for such structures in the two-photon mass spectrum in meson–nuclear interactions at a momentum of 7 GeV/
c
at the Hyperon-M experiment of the U-70 accelerator complex. An upper limit has been established on the ratio of the cross section for the formation of unknown resonance structures to the cross section for the production of
-meson
at the 95% confidence level.
The modification of the spectral function of vector mesons in nuclear matter is predicted in many theoretical models. However, the existing experimental results for testing these models are ...contradictory. Possible effects of the modification of the mass and width of ω mesons produced in the collisions of 7-GeV/
c
positively charged mesons with C, Be, Al, Cu, Sn, and Pb nuclear targets have been sought in the Hyperon-M experiment. The measured mass and width of ω mesons produced on the indicated nuclei are in agreement with each other with a high accuracy, which does not confirm the theoretical models predicting modification of the mass and/or width of the ω meson in nuclear matter.
The feasibility of detection of the charmonium states
at the ALICE experiment at the Large Hadron Collider is studied. It is demonstrated that the current resolution of the tracking system and the ...electromagnetic calorimeter is sufficient for signal discrimination of
and
. Kinematic selection cuts are optimized for selection of these charmonium states.
Abstact
—The paper presents the upgrade project of the Hyperon-M experiment in the positive beam line of the U-70 accelerator complex in Protvino to study hadron-nuclear interaction mechanisms. It is ...proposed that the setup be upgraded to study the excited states of secondary nuclei formed by different types of primary hadron–nuclear interaction using precision nuclear gamma-ray spectroscopy. This could open a new direction of the nuclear physics at the junction with the physics of elementary particles at intermediate energies.
ALICE experiment at LHC collects data in
pp
collisions at
1497-1
= 0.9, 2.76, and 7 TeV and in PbPb collisions at 2.76 TeV. Highlights of the detector performance and an overview of experimental ...results measured with ALICE in
pp
and
AA
collisions are presented in this paper. Physics with protonproton collisions is focused on hadron spectroscopy at low and moderate
p
t
. Measurements with lead-lead collisions are shown in comparison with those in
pp
collisions, and the properties of hot quark matter are discussed.
The feasibility of detection of the charmonium states Formula omitted at the ALICE experiment at the Large Hadron Collider is studied. It is demonstrated that the current resolution of the tracking ...system and the electromagnetic calorimeter is sufficient for signal discrimination of Formula omitted and Formula omitted. Kinematic selection cuts are optimized for selection of these charmonium states.
The
π
0
,
η
,
K
0
,
ω
, and
f
2
(1270) masses were measured at the HYPERON-Msetup in meson-nucleus interactions at a momentum of 7 GeV/
c
by using six nuclear targets: Be, C, Al, Cu, Sn, and Pb. The ...experiment in question proved to be insensitive to the expected effects of a modification to the omega-meson mass in nuclear matter. As for the
f
2
(1270) meson, its mass and width values averaged over all experimental data,
= 1275.8 ± 1.0(stat.) ± 0.4(syst.) MeV/
c
2
and
= 190.3 ± 1.9(stat.) ± 1.8(syst.) MeV/
c
2
, agree well with the world-average values. At the same time, our experimental data do not rule out the possible effect of an in-medium modification to the
f
2
(1270)-meson mass for heavy nuclei at a level better than 0.4%.
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