We present a measurement of the momentum spectra of π±, K±, p±, Λ, ¯Λ, and K0S produced in interactions of negatively charged pions with carbon nuclei at beam momenta of 158 and 350 GeV/c. The total ...production cross sections are measured as well. The data were collected with the large-acceptance spectrometer of the fixed target experiment NA61/SHINE at the CERN SPS. The obtained double-differential p−pT spectra provide a unique reference dataset with unprecedented precision and large phase-space coverage to tune models used for the simulation of particle production in extensive air showers in which pions are the most numerous projectiles.
The critical point of dense, strongly interacting matter is searched for at the CERN SPS in
40
Ar +
45
Sc collisions at 150
A
Ge V /
c
. The dependence of second-order scaled factorial moments of ...proton multiplicity distribution on the number of subdivisions of transverse momentum space is measured. The intermittency analysis is performed using both transverse momentum and cumulative transverse momentum. For the first time, statistically independent data sets are used for each subdivision number. The obtained results do not indicate any statistically significant intermittency pattern. An upper limit on the fraction of correlated proton pairs and the power of the correlation function is obtained based on a comparison with the Power-law Model developed for this purpose.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper reports measurements of two-pion femtoscopic correlations in Be+Be collisions at a beam momentum of 150
A
GeV
/
c
(energy available in the center-of-mass system for nucleon pair
s
NN
=
...16.84
GeV) by the NA61/SHINE experiment at the CERN SPS accelerator. The obtained momentum space correlation functions can be well described by a Lévy distributed source model. The transverse mass dependence of the Lévy source parameters is presented, and their possible theoretical interpretations are discussed. The results show that the Lévy exponent
α
is approximately constant as a function of
m
T
, and far from both the Gaussian case of
α
=
2
or the conjectured value at the critical endpoint,
α
=
0.5
. The radius scale parameter
R
shows a slight decrease in
m
T
, which can be explained as a signature of transverse flow. Finally, an approximately constant trend of the intercept parameter
λ
as a function of
m
T
was observed, similar to previous NA44 S + Pb results (obtained with a Gaussian approximation, but unlike RHIC results).
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper presents multiplicity measurements of charged hadrons produced in 120 GeV/$c$ proton-carbon interactions. The measurements were made using data collected at the NA61/SHINE experiment ...during two different data-taking periods, with increased phase space coverage in the second configuration due to the addition of new subdetectors. Particle identification via $dE/dx$ was employed to obtain double-differential production multiplicities of $\pi^+$, $\pi^-$, $p$, $\bar{p}$, $K^+$ and $K^-$. These measurements are presented as a function of laboratory momentum in intervals of laboratory polar angle covering the range from 0 to 450 mrad. They provide crucial inputs for current and future long-baseline neutrino experiments, where they are used to estimate the initial neutrino flux.
The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the onset of deconfinement in strongly interacting matter through a beam energy scan of particle production in collisions of ...nuclei of varied sizes. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of
π
±
,
K
±
,
p
and
p
¯
produced in
40
Ar+
45
Sc
collisions at beam momenta of 13
A
, 19
A
, 30
A
, 40
A
, 75
A
and 150
A
Ge
V
/
c
. The analysis uses the 10% most central collisions, where the observed forward energy defines centrality. The energy dependence of the
K
±
/
π
±
ratios as well as of inverse slope parameters of the
K
±
transverse mass distributions are placed in between those found in inelastic
p
+
p
and central Pb + Pb collisions. The results obtained here establish a system-size dependence of hadron production properties that so far cannot be explained either within statistical or dynamical models.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract The critical point of strongly interacting matter is searched for at the CERN SPS by the NA61/SHINE experiment in central $$^{40}$$ 40 Ar + $$^{45}$$ 45 Sc collisions at 13 A , 19 A , 30 ...A , 40 A , and 75 A GeV/ c . The dependence of the second-order scaled factorial moments of proton multiplicity distributions on the number of subdivisions in transverse momentum space is measured. The intermittency analysis uses statistically independent data sets for every subdivision in transverse and cumulative-transverse momentum variables. The results obtained do not indicate the searched intermittent pattern. An upper limit on the fraction of correlated protons and the intermittency index is obtained based on a comparison with the Power-law Model.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last ...Call for Predictions', held from May 14th to June 10th 2007.
Abstract
This paper reports measurements of two-pion femtoscopic correlations in Be+Be collisions at a beam momentum of 150
$$A\,\hbox {GeV}\!/\!c$$
A
GeV
/
c
(energy available in the center-of-mass ...system for nucleon pair
$$\sqrt{s_{\text {NN}}} = 16.84$$
s
NN
=
16.84
GeV) by the NA61/SHINE experiment at the CERN SPS accelerator. The obtained momentum space correlation functions can be well described by a Lévy distributed source model. The transverse mass dependence of the Lévy source parameters is presented, and their possible theoretical interpretations are discussed. The results show that the Lévy exponent
$$\alpha $$
α
is approximately constant as a function of
$$m_{\text {T}}$$
m
T
, and far from both the Gaussian case of
$$\alpha = 2$$
α
=
2
or the conjectured value at the critical endpoint,
$$\alpha = 0.5$$
α
=
0.5
. The radius scale parameter
R
shows a slight decrease in
$$m_{\text {T}}$$
m
T
, which can be explained as a signature of transverse flow. Finally, an approximately constant trend of the intercept parameter
$$\lambda $$
λ
as a function of
$$m_{\text {T}}$$
m
T
was observed, similar to previous NA44 S + Pb results (obtained with a Gaussian approximation, but unlike RHIC results).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Many respondent-driven sampling (RDS) methodologies have been employed to investigate hard-to-reach populations; however, these methodologies present some limits. We describe a minimally investigated ...RDS methodology in which peer recruitment and interviewing are phone-based. The feasibility of the methodology, field experiences, validity of RDS assumptions and characteristics of the sample obtained are discussed.
We conducted a phone-based RDS survey among men who have sex with men (MSM) aged 18 or above and living in Côte d'Ivoire. Eight initial MSM across Côte d'Ivoire were selected. Participants were asked to call a hotline to be registered and interviewed by phone. After the participants completed the questionnaire, they were asked to recruit a maximum of 3 MSM from their acquaintances.
During the 9 months of the survey, 576 individuals called the hotline, and 518 MSM completed the questionnaire. The median delay between the invitation to participate and the completion of the questionnaire by peer-recruited MSM was 4 days IQR: 1-12. The recruitment process was not constant, with high variation in the number of people who called the hotline during the survey period. RDS chain convergence to equilibrium was reached within 6 waves for most of the selected variables. For the network size estimation assumption, participants who incorrectly estimated their network size were observed. Regarding the sample obtained, MSM were recruited from all the regions of Côte d'Ivoire with frequent interregional recruitment; 23.5% of MSM were recruited by someone who does not live in the same region. Compared to the MSM who participated in two other surveys in Côte d'Ivoire, the MSM in our sample were less likely to know about an MSM non-governmental organisation. However, MSM aged 30 years old and above and those with a low level of education were underrepresented in our sample.
We show that phone-based RDS surveys among MSM are feasible in the context of sub-Saharan Africa. Compared to other classical RDS survey methodologies, the phone-based RDS methodology seems to reduce selection bias based on geography and proximity with the MSM community. However, similar to other methodologies, phone-based RDS fails to reach older and less-educated MSM.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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