Abstract The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various ...sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $$\pi ^\pm $$ π ± , $$K^\pm $$ K ± , p and $$\bar{p}$$ p ¯ produced in the 20% most central $$^7$$ 7 Be+ $$^9$$ 9 Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150A $${\mathrm{Ge} \mathrm{V}}\!/\!c$$ Ge V / c . The energy dependence of the $$K^\pm $$ K ± / $$\pi ^\pm $$ π ± ratios as well as of inverse slope parameters of the $$K^\pm $$ K ± transverse mass distributions are close to those found in inelastic p+p reactions. The new results are compared to the world data on p+p and Pb+Pb collisions as well as to predictions of the Epos, Urqmd, Ampt, Phsd and Smash models.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A measurement of charged hadron pair correlations in two-dimensional $$\Delta \eta \Delta \phi $$ Δ η Δ ϕ space is presented. The analysis is based on total 30 million central Be + Be ...collisions observed in the NA61/SHINE detector at the CERN SPS for incident beam momenta of 19A, 30A, 40A, 75A, and 150A $$\text {Ge} \text {V}/c$$ Ge / c . Measurements were carried out for unlike-sign and like-sign charge hadron pairs independently. The $$C(\Delta \eta ,\Delta \phi )$$ C ( Δ η , Δ ϕ ) correlation functions were compared with results from a similar analysis on p + p interactions at similar beam momenta per nucleon. General trends of the back-to-back correlations are similar in central Be + Be collisions and p + p interactions, but are suppressed in magnitude due to the increased combinatorial background. Predictions from the Epos and UrQMD models are compared to the measurements. Evolution of an enhancement around $$(\Delta \eta ,\Delta \phi ) = (0,0)$$ ( Δ η , Δ ϕ ) = ( 0 , 0 ) with incident energy is observed in central Be + Be collisions. It is not predicted by both models and almost non-existing in proton–proton collisions at the same momentum per nucleon.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract The NA61/SHINE collaboration studies at the CERN Super Proton Synchrotron (SPS) the onset of deconfinement in hadronic matter by the measurement of particle production in collisions of ...nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra and mean multiplicities of $$\pi ^{-}$$ π - mesons produced in the 5% most central $$^7$$ 7 Be + $$^9$$ 9 Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150 $$A\,\text{ GeV }\!/\!c$$ A GeV / c obtained by the so-called $$h^-$$ h - method which does not require any particle identification. The shape of the transverse mass spectra differs from the shapes measured in central Pb + Pb collisions and inelastic p+p interactions. The normalized width of the rapidity distribution decreases with increasing collision energy and is in between the results for inelastic nucleon–nucleon and central Pb + Pb collisions. The mean multiplicity of pions per wounded nucleon in central $$^7$$ 7 Be + $$^9$$ 9 Be collisions is close to that in central Pb + Pb collisions up to 75 $$A\,\text{ GeV }\!/\!c$$ A GeV / c . However, at the top SPS energy the result lies between those for nucleon–nucleon and Pb + Pb interactions. The results are discussed in the context of predictions for the onset of deconfinement at the CERN SPS collision energies.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract The production of $$\Xi (1321)^{-}$$ Ξ ( 1321 ) - and $$\overline{\Xi }(1321)^{+}$$ Ξ ¯ ( 1321 ) + hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam ...momentum of 158 $$\hbox {Ge}\hbox {V}\!/\!c$$ Ge / c . Double differential distributions in rapidity $${y}$$ y and transverse momentum $$p_{T}$$ p T are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both $${\Xi }{^-} $$ Ξ - and $$\overline{\Xi }{^+} $$ Ξ ¯ + . The rapidity and transverse momentum spectra are compared to transport model predictions. The $${\Xi }{^-} $$ Ξ - mean multiplicity in inelastic p+p interactions at 158 $$\hbox {Ge}\hbox {V}\!/\!c$$ Ge / c is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair.
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Inclusive production of $\Lambda $ -hyperons was measured with the large acceptance NA61/SHINE spectrometer at the CERN SPS in inelastic p+p interactions at beam momentum of 158 ...${\mathrm{GeV}}\!/\!c$ . Spectra of transverse momentum and transverse mass as well as distributions of rapidity and x$_{_F}$ are presented. The mean multiplicity was estimated to be $0.120\,{\pm }\,0.006\,(stat.)\,{\pm }0.010\,(sys.)$ . The results are compared with previous measurements and predictions of the Epos, Urqmd and Fritiof models.
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Abstract The measurement of $$K^{*}(892)^0$$ K∗(892)0 resonance production via its $$K^{+}\pi ^{-}$$ K+π- decay mode in inelastic p+p collisions at beam momentum 158 $$\text{ Ge }\text{ V }\!/\!c$$ ...GeV/c ($$\sqrt{s_{NN}}=17.3$$ sNN=17.3 $$\text{ Ge }\text{ V }$$ GeV ) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The template method was used to extract the $$K^{*}(892)^0$$ K∗(892)0 signal and double-differential transverse momentum and rapidity spectra were obtained. The full phase-space mean multiplicity of $$K^{*}(892)^0$$ K∗(892)0 mesons was found to be $$(78.44 \pm 0.38 \mathrm {(stat)} \pm 6.0 \mathrm {(sys)) \cdot 10^{-3}}$$ (78.44±0.38(stat)±6.0(sys))·10-3 . The NA61/SHINEresults are compared with the Epos1.99 and Hadron Resonance Gas models as well as with world data from p+p and nucleus–nucleus collisions.
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Abstract Results on $$\phi $$ ϕ meson production in inelastic $$p + p$$ p+p collisions at CERN SPS energies are presented. They are derived from data collected by the NA61/SHINE fixed target ...experiment, by means of invariant mass spectra fits in the $$\phi \rightarrow K^+ K^- $$ ϕ→K+K- decay channel. They include the first ever measured double differential spectra of $$\phi $$ ϕ mesons as a function of rapidity $$y$$ y and transverse momentum $$p_{\text {T}}$$ pT for proton beam momenta of $$80 \, \hbox {GeV}/c$$ 80GeV/c and $$158 \, \hbox {GeV}/c$$ 158GeV/c , as well as single differential spectra of $$y$$ y or $$p_{\text {T}}$$ pT for beam momentum of $$40 \, \hbox {GeV}/c$$ 40GeV/c . The corresponding total $$\phi $$ ϕ yields per inelastic $$p + p$$ p+p event are obtained. These results are compared with existing data on $$\phi $$ ϕ meson production in $$p + p$$ p+p collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of $$\phi $$ ϕ mesons in $$p + p$$ p+p reactions is confronted with that occurring in $$\mathrm{Pb} + \mathrm{Pb}$$ Pb+Pb collisions, and the experimental results are compared with model predictions. It appears that none of the considered models can properly describe all the experimental observations.
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Abstract
The measurement of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
resonance production via its
$$K^{+}\pi ^{-}$$
K
+
π
-
decay mode in inelastic p+p collisions at beam momentum 158
$$\text{ Ge }\text{ V ...}\!/\!c$$
Ge
V
/
c
(
$$\sqrt{s_{NN}}=17.3$$
s
NN
=
17.3
$$\text{ Ge }\text{ V }$$
Ge
V
) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The
template
method was used to extract the
$$K^{*}(892)^0$$
K
∗
(
892
)
0
signal and double-differential transverse momentum and rapidity spectra were obtained. The full phase-space mean multiplicity of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
mesons was found to be
$$(78.44 \pm 0.38 \mathrm {(stat)} \pm 6.0 \mathrm {(sys)) \cdot 10^{-3}}$$
(
78.44
±
0.38
(
stat
)
±
6.0
(
sys
)
)
·
10
-
3
. The NA61/SHINEresults are compared with the
Epos1.99
and Hadron Resonance Gas models as well as with world data from p+p and nucleus–nucleus collisions.
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Abstract Measurements of the $$\pi ^\pm $$ π± , $$K^\pm $$ K± , and proton double differential yields emitted from the surface of the 90-$$\hbox {cm}$$ cm -long carbon target (T2K replica) were ...performed for the incoming $$31\,$$ 31 $$\hbox {GeV}\!/\!c$$ GeV/c protons with the NA61/SHINE spectrometer at the CERN SPS using data collected during 2010 run. The double differential $$\pi ^\pm $$ π± yields were measured with increased precision compared to the previously published NA61/SHINE results, while the $$K^\pm $$ K± and proton yields were obtained for the first time. A strategy for dealing with the dependence of the results on the incoming proton beam profile is proposed. The purpose of these measurements is to reduce significantly the (anti)neutrino flux uncertainty in the T2K long-baseline neutrino experiment by constraining the production of (anti)neutrino ancestors coming from the T2K target.
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