We present a measurement of the muon neutrino–nucleon inclusive charged current cross section, off an isoscalar target, in the neutrino energy range 2.5⩽Eν⩽40 GeV. The significance of this ...measurement is its precision, ±4% in 2.5⩽Eν⩽10 GeV, and ±2.6% in 10⩽Eν⩽40 GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.
Results on $\phi $ meson production in inelastic $p + p$ 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^- $ decay channel. They include the first ever measured double differential spectra of $\phi $ mesons as a function of rapidity $y$ and transverse momentum $p_{\text {T}}$ for proton beam momenta of $80 \, \hbox {GeV}/c$ and $158 \, \hbox {GeV}/c$, as well as single differential spectra of $y$ or $p_{\text {T}}$ for beam momentum of $40 \, \hbox {GeV}/c$. The corresponding total $\phi $ yields per inelastic $p + p$ event are obtained. These results are compared with existing data on $\phi $ meson production in $p + p$ collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of $\phi $ mesons in $p + p$ reactions is confronted with that occurring in $\mathrm{Pb} + \mathrm{Pb}$ 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.
A measurement of charged hadron pair correlations in two-dimensional $\Delta \eta \Delta \phi $ 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 $\text {Ge} \text {V}/c$. Measurements were carried out for unlike-sign and like-sign charge hadron pairs independently. The $C(\Delta \eta ,\Delta \phi )$ 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 $(\Delta \eta ,\Delta \phi ) = (0,0)$ 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.
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
π
-
mesons produced in the 5% most
central
7
Be +
9
Be collisions at beam momenta of 19
A
, 30
A
, 40
A
, 75
A
and 150
A
GeV
/
c
obtained by the so-called
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
Be +
9
Be collisions is close to that in
central
Pb + Pb collisions up to 75
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.
The measurements of open charm production was proposed as an important tool to investigate the properties of the hot and dense matter formed in nucleus-nucleus collisions as well as to provide the ...means for model independent interpretation of the existing data on J/ψ suppression. Recently, the experimental setup of the NA61/SHINE experiment was supplemented with a Vertex Detector which was motivated by the importance and the possibility of the first direct measurements of open charm meson production in heavy ion collisions at SPS energies. First test data taken in December 2016 on Pb+Pb collisions at 150A GeV/c allowed to validate the general concept of D0 meson detection via its D0 → π+ + K− decay channel and delivered a first indication of open charm production.
The physics motivation of open charm measurements at SPS energies, pilot results on open charm production, and finally, the future plans of open charm measurements in the NA61/SHINE experiment after LS2 are presented.
Preliminary results on the ϕ (1020) meson production in inelastic proton-proton collisions measured by the NA61/SHINE experiment at the CERN SPS are presented in these proceedings. The results ...include the first ever differential pT and y measurements at beam momenta of 40 and 80 GeV and the most ever detailed experimental data at 158GeV. The comparison of p + p to Pb + Pb results shows a non-trivial system size dependence of the widths of the rapidity distributions for ϕ mesons, contrasting with that of other hadrons. The results are furthermore compared to the world data on ϕ meson production, demonstrating the better accuracy achieved by the NA61/SHINE experiment, and to several models. None of the models is found to be able to describe simultaneously the shape of transverse momentum spectra, the shape of rapidity distribution and the total yield.
Measurements of the $\pi ^\pm $ , $K^\pm $ , and proton double differential yields emitted from the surface of the 90- $\hbox {cm}$ -long carbon target (T2K replica) were performed for the incoming ...$31\,$ $\hbox {GeV}\!/\!c$ protons with the NA61/SHINE spectrometer at the CERN SPS using data collected during 2010 run. The double differential $\pi ^\pm $ yields were measured with increased precision compared to the previously published NA61/SHINE results, while the $K^\pm $ 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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