The experiment of the NA61/SHINE Collaboration at the CERN SPS is performing a unique study of the phase diagram of strongly interacting matter by varying collision energy and nuclear mass number of ...colliding nuclei. In central Pb + Pb collisions, the experiment of the NA49 Collaboration found structures in the energy dependence of several observables in the energy range of the CERN SPS that had been predicted for the transition to a deconfined phase. New measurements of the NA61/SHINE Collaboration find intriguing similarities in $p + p$ interactions for which no deconfinement transition is expected at the energies of the SPS. Possible implications will be discussed.
Precise knowledge of hadron production rates in the generation of neutrino beams is necessary for accelerator-based neutrino experiments to achieve their physics goals. NA61/SHINE, a large-acceptance ...hadron spectrometer, has recorded hadron+nucleus interactions relevant to ongoing and future long-baseline neutrino experiments at Fermi National Accelerator Laboratory. This paper presents three analyses of interactions of 60 GeV/c π+ with thin, fixed carbon and beryllium targets. Integrated production and inelastic cross sections were measured for both of these reactions. In an analysis of strange, neutral hadron production, differential production multiplicities of KS0, Λ and Λ¯ were measured. Lastly, in an analysis of charged hadron production, differential production multiplicities of π+, π−, K+, K− and protons were measured. These measurements will enable long-baseline neutrino experiments to better constrain predictions of their neutrino flux in order to achieve better precision on their neutrino cross section and oscillation measurements.
Pentaquark states have been extensively investigated theoretically in the context of the constituent quark model. In this paper results of an experimental search for pentaquarks in the Ξ−π−, Ξ−π+, ...¯Ξ+π− and ¯ Ξ+π+ invariant mass spectra in proton-proton interactions at √s = 17.3 GeV are presented. Previous possible evidence from the NA49 collaboration of the existence of a narrow Ξ−π− baryon resonance in p + p interactions is not confirmed with almost 10 times greater event statistics. The search was performed using the NA61/SHINE detector which reuses the main components of the NA49 apparatus. No signal was observed with either the selection cuts of NA49 or newly optimized cuts.
This paper presents several measurements of total production cross sections and total inelastic cross sections for the following reactions: π++C, π++Al, K++C, K++Al at 60 GeV/c, π++C and π++Al at 31 ... GeV/c. The measurements were made using the NA61/SPS Heavy Ion and Neutrino Experiment spectrometer at the CERN Super Proton Synchrotron (SPS). Comparisons with previous measurements are given and good agreement is seen. These interaction cross sections measurements are a key ingredient for neutrino flux prediction from the reinteractions of secondary hadrons in current and future accelerator-based long-baseline neutrino experiments.
We present measurements of ρ0, ω and K∗0 spectra in π-+ C production interactions at 158 GeV/c and ρ0 spectra at 350 GeV/c using the NA61/SHINE spectrometer at the CERN SPS. Spectra are presented as ...a function of the Feynman’s variable xF in the range 0<xF<1 and 0<xF<0.5 for 158 and 350 GeV/c respectively. Furthermore, we show comparisons with previous measurements and predictions of several hadronic interaction models. These measurements are essential for a better understanding of hadronic shower development and for improving the modeling of cosmic ray air showers.
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.
Measurements of the
π
±
,
K
±
, and proton double differential yields emitted from the surface of the 90-
cm
-long carbon target (T2K replica) were performed for the incoming
31
GeV
/
c
protons with ...the NA61/SHINE spectrometer at the CERN SPS using data collected during 2010 run. The double differential
π
±
yields were measured with increased precision compared to the previously published NA61/SHINE results, while the
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.
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.
Results on
ϕ
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
ϕ
→
K
+
K
-
decay channel. They include the first ever measured double differential spectra of
ϕ
mesons as a function of rapidity
y
and transverse momentum
p
T
for proton beam momenta of
80
GeV
/
c
and
158
GeV
/
c
, as well as single differential spectra of
y
or
p
T
for beam momentum of
40
GeV
/
c
. The corresponding total
ϕ
yields per inelastic
p
+
p
event are obtained. These results are compared with existing data on
ϕ
meson production in
p
+
p
collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of
ϕ
mesons in
p
+
p
reactions is confronted with that occurring in
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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