Best practice policies for male infertility Sharlip, Ira D; Jarow, Jonathan P; Belker, Arnold M ...
Fertility and sterility,
05/2002, Letnik:
77, Številka:
5
Journal Article
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.
A high-statistics data sample of the
K
+
decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP)
a
in ...the decay
K
+
→
π
+
π
0
a
. No signal is observed, and the upper limits for the branching ratio of the decay are calculated. The
90
%
confidence level upper limit changes from
2.5
·
10
-
6
to
2
·
10
-
7
for the ALP mass from 0 to 200 MeV/
c
2
, except for the region of
π
0
mass, where the upper limit is
4.4
·
10
-
6
.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
5.
Observation of K+→π+π0π0γ decay Artamonov, A. V.; Bychkov, V. N.; Donskov, S. V. ...
The European physical journal. C, Particles and fields,
04/2024, Letnik:
84, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The
K
+
→
π
+
π
0
π
0
γ
decay is observed by the OKA collaboration. About 60 events of the decay observed with signal:noise
≈
1
. The branching ratio obtained by normalization to
K
+
→
π
+
π
0
π
0
is ...measured to be
(
3.7
±
0.9
(
s
t
a
t
)
±
0.3
(
s
y
s
t
)
)
×
10
-
6
for
E
γ
∗
>
10
MeV
. The branching ratio,
γ
energy spectrum and angular distribution are consistent with ChPT prediction.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
There are several theoretical models for describing longitudinal vibrations of a rod. The simplest and most common model is based on the wave equation. Less common is the model taking into account ...lateral displacement (Rayleigh correction). The Bishop model is considered to be superior, considering both transverse displacement and shear deformation. It would seem that the more improved the theoretical model, the better its agreement should be with experimental data. However, that turns out not to be quite the case when compared to an actual experimental spectrum of longitudinal rod vibrations over a large base of natural frequencies. Moreover, the most complex Bishop model turns out to be relatively weak. Comparisons were made for a smooth long cylindrical rod. Also discussed are the questions of specifying the velocity of longitudinal waves and Poisson’s ratio of the rod material using experimentally obtained frequencies.
The analysis of amplitude spectra from a thin polystyrene-based scintillation counter on muon-enriched and hadron beams of channel 18 of the U-70 accelerator complex in Protvino has been presented. ...On the basis of statistics of 150 million events on the Hyperon-M setup, the contribution of the
-fragmentation processes are highlighted and the cross sections of these processes on hadron and pion beams with a momentum of 7 GeV/
c
have been measured. In the future, the obtained result may be of interest for the method of analyzing the age of gas fields based on the concentration of helium in natural gas, the formation of which is possible in the reaction of
fragmentation of carbon nuclei in
interactions induced by high-energy cosmic muons.
Measurements of multiplicity and transverse momentum fluctuations of charged particles were performed in inelastic p+p interactions at 20, 31, 40, 80, and 158
GeV
/
c
beam momentum. Results for the ...scaled variance of the multiplicity distribution and for three strongly intensive measures of multiplicity and transverse momentum fluctuations
Δ
P
T
,
N
,
Σ
P
T
,
N
and
Φ
p
T
are presented. For the first time the results on fluctuations are fully corrected for experimental biases. The results on multiplicity and transverse momentum fluctuations significantly deviate from expectations for the independent particle production. They also depend on charges of selected hadrons. The string-resonance Monte Carlo models
Epos
and
U
r
qmd
do not describe the data. The scaled variance of multiplicity fluctuations is significantly higher in inelastic p+p interactions than in central Pb+Pb collisions measured by NA49 at the same energy per nucleon. This is in qualitative disagreement with the predictions of the Wounded Nucleon Model. Within the statistical framework the enhanced multiplicity fluctuations in inelastic p+p interactions can be interpreted as due to event-by-event fluctuations of the fireball energy and/or volume.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
Abstract
We present a study of a directional search for Dark Matter boosted forward when scattered by cosmic-ray nuclei, using a module of the NEWSdm experiment. The boosted Dark Matter flux at the ...edge of the Earth's atmosphere is expected to be pointing to the Galactic Center, with a flux 15 to 20 times larger than in the transverse direction.
The module of the NEWSdm experiment consists of a 10 kg stack of Nano Imaging Trackers, i.e. newly developed nuclear emulsions with AgBr crystal sizes down to a few tens of nanometers. The module is installed on an equatorial telescope.
The relatively long recoil tracks induced by boosted Dark Matter, combined with the nanometric granularity of the emulsion, result in an extremely low background.
This makes an installation at the INFN Gran Sasso laboratory, both on the surface and underground, viable. A comparison between the two locations is made.
The angular distribution of nuclear recoils induced by boosted Dark Matter in the emulsion films at the surface laboratory is expected to show an excess with a factor of 3.5 in the direction of the Galactic Center. This excess allows for a Dark Matter search with directional sensitivity.
The surface laboratory configuration prevents the deterioration of the signal in the rock overburden and it emerges as the most powerful approach for a directional observation of boosted Dark Matter with high sensitivity.
We show that, with this approach, a 10 kg module of the NEWSdm experiment exposed for one year at the Gran Sasso surface laboratory can probe Dark Matter masses between 1 keV/c
2
and 1 GeV/c
2
and cross-section values down to 10
-30
cm
2
with a directional sensitive search.
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