This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV/c protons with C, Be, Al targets and 120 GeV/c protons with C and Be ...targets. The analysis is performed using the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. First measurements are obtained using protons at 120 GeV/c, while the results for protons at 60 GeV/c are compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.
We calculate the invariant and helicity amplitudes for the transitions Λb→Λ(*)(JP)+J/ψ, where the Λ(*)(JP) are Λ(sud)-type ground and excited states with JP quantum numbers JP=12±, 32±. The ...calculations are performed in the framework of a covariant confined quark model previously developed by us. We find that the values of the helicity amplitudes for the Λ*(1520,32−) and the Λ*(1890,32+) are suppressed compared with those for the ground state Λ(1116,12+) and the excited state Λ*(1405,12−). This analysis is important for the identification of the hidden charm pentaquark states Pc+(4380) and Pc+(4450) which were discovered in the decay chain Λb0→Pc+(→pJ/ψ)+K− because the cascade decay chain Λb→Λ*(32±)(→pK−)+J/ψ involves the same final state.
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.
We analyse available experimental data on the total and differential charged-current cross sections for quasielastic ν
μ
N and ν̄
μ
N scattering, obtained with a variety of nuclear targets in the ...accelerator experiments at ANL, BNL, FNAL, CERN, and IHEP, dating from the end of sixties to the present day. The data are used to adjust the poorly known value of the axial-vector mass of the nucleon.
Measurements of inclusive spectra and mean multiplicities of
π
±
, K
±
, p and
p
¯
produced in inelastic p + p interactions at incident projectile momenta of 20, 31, 40, 80 and 158
GeV
/
c
(
s
=
...6.3, 7.7, 8.8, 12.3 and 17.3
GeV
, respectively) were performed at the CERN Super Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer. Spectra are presented as function of rapidity and transverse momentum and are compared to predictions of current models. The measurements serve as the baseline in the NA61/SHINE study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter.
Abstract
Measurements of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
resonance production via its
$$K^{+}\pi ^{-}$$
K
+
π
-
decay mode in inelastic
p+p
collisions at beam momenta 40 and 80
$$\text{ GeV }\!/\!c$$
...GeV
/
c
(
$$\sqrt{s_{NN}}=8.8$$
s
NN
=
8.8
and 12.3
$$\text{ GeV }$$
GeV
) are 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. Transverse momentum and rapidity spectra were obtained. The mean multiplicities of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
mesons were found to be
$$(35.1 \pm 1.3 \mathrm {(stat)} \pm 3.6 \mathrm {(sys))} \cdot 10^{-3}$$
(
35.1
±
1.3
(
stat
)
±
3.6
(
sys
)
)
·
10
-
3
at 40
$$\text{ GeV }\!/\!c$$
GeV
/
c
and
$$(58.3 \pm 1.9 \mathrm {(stat)} \pm 4.9 \mathrm {(sys))} \cdot 10^{-3}$$
(
58.3
±
1.9
(
stat
)
±
4.9
(
sys
)
)
·
10
-
3
at 80
$$\text{ GeV }\!/\!c$$
GeV
/
c
. The NA61/SHINE results are compared with the
Epos1.99
and Hadron Resonance Gas models as well as with world data. The transverse mass spectra of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
mesons and other particles previously reported by NA61/SHINE were fitted within the Blast-Wave model. The transverse flow velocities are close to 0.1–0.2 of the speed of light and are significantly smaller than the ones determined in heavy nucleus-nucleus interactions at the same beam momenta.
Measurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158 Formula omitted beam momentum are presented. Three different measures of ...multiplicity fluctuations are used: the scaled variance Formula omitted and strongly intensive measures Formula omitted and Formula omitted. These fluctuation measures involve second and first moments of joint multiplicity distributions. Data analysis is preformed using the Identity method which corrects for incomplete particle identification. Strongly intensive quantities are calculated in order to allow for a direct comparison to corresponding results on nucleus-nucleus collisions. The results for different hadron types are shown as a function of collision energy. A comparison with predictions of string-resonance Monte-Carlo models: Epos, Smash and Venus, is also presented.
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 $\pi ^{-}$ mesons produced in the 5% most central$^7$Be + $^9$Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150$A\,\text{ GeV }\!/\!c$ 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$A\,\text{ GeV }\!/\!c$. 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.
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.
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