scholarly journals Latest Results from the NA61/SHINE Experiment

KnE Energy ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 188 ◽  
Author(s):  
D T Larsen
Keyword(s):  
Critical Point ◽  
Energy Dependence ◽  
System Size ◽  
Beam Momentum ◽  
Strong Interactions ◽  
Proton Synchrotron ◽  
Momentum Range ◽  
Super Proton Synchrotron ◽  
Hadron Spectra ◽  
Onset Of Deconfinement

The NA61/SHINE experiment at the CERN Super Proton Synchrotron is pursuing a rich programme on strong interactions, which covers the study of the onset of deconfinement and aims to discover the critical point of strongly interacting matter by performing an energy and system-size scan over the full CERN SPS beam momentum range. So far the scans of p+p, p+Pb, Be+Be, and Ar+Sc interactions have been completed, samples of Pb+Pb data at three energies have already been taken and Xe+La collisions will be registered this year. Results from the different reactions are now emerging, in particular the energy dependence of hadron spectra and yields as well as fluctuations. This contribution presents status and preliminary results from this effort, as well as an outlook for future extensions of the strong interactions programme.

scholarly journals The onsets of deconfinement and fireball of NA61/SHINE

2019 ◽  
Vol 199 ◽  
pp. 04010
Author(s):  
Dag Larsen
Keyword(s):  
Critical Point ◽  
Theoretical Models ◽  
System Size ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Strong Interactions ◽  
Momentum Range ◽  
Ion Collisions ◽  
Intermediate Size ◽  
Onset Of Deconfinement

The NA61/SHINE experiment at the CERN SPS is pursuing a rich programme on strong interactions, covering the study of onset of deconfinement and aims to discover the critical point of strongly interacting matter by performing an energy and system-size scan at the full CERN SPS momentum range. These scans of p+p, p+Pb, Be+Be, Ar+Sc and Pb+Pb have been mostly completed with Xe+La last year (more Pb+Pb to to taken this year). Results from the different reactions are now emerging. As a surprise, some measurements did not scale smoothly. In particular, for the K+/π+ ratio, Be+Be collisions behaved similarly to p+p (as superposition of nucleon collisions), while Ar+Sc was closer to Pb+Pb collisions. This step can not be explained by onset of deconfinement, and may indicate that there is also a onset of fireball in relativistic heavy ion collisions. A review of the results as well as possible interpretation will be presented. The theoretical models (SMES, PHSD) describe onset of deconfinement at the heaviest system relatively well. However, no model describes the behaviour of data at previously unmeasured collisions of light and intermediate size ions. The onset of fireball is not described by any model.

scholarly journals Investigating the “kink” plot as a signal of the onset of deconfinement

2018 ◽  
Vol 57 (4) ◽  
Author(s):  
Michał Naskręt
Keyword(s):  
Early Stage ◽  
System Size ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Hadronic Matter ◽  
Proton Synchrotron ◽  
Super Proton Synchrotron ◽  
Central Collisions ◽  
The Mean ◽  
Onset Of Deconfinement

One of the physics goals of the NA61/SHINE collaboration at the CERN Super Proton Synchrotron is to study the phase diagram of hadronic matter. To this end, a series of heavy ion collision measurements are performed. It is believed that above a certain collision energy and system size a phase transition between the hadronic matter and quark–gluon plasma occurs. A number of observables have been developed to determine which of the phases was created at the early stage of the collision. This report discusses the dependence of the ratio of the mean number of produced pions to the mean number of wounded nucleons on the Fermi energy measure. For comparison with other measurements this is often presented in the form of the “kink” plot. This plot is presented enriched with preliminary results for 40Ar+45Sc central collisions at 13A, 19A, 30A, 40A, 75A and 150A GeV/c beam momenta. The results are finally compared to data from other experiments.

scholarly journals Spectra and mean multiplicities of $$\pi ^{-}$$ in central $${}^{40}$$Ar+$${}^{45}$$Sc collisions at 13A, 19A, 30A, 40A, 75A and 150$$A\,\text{ Ge }\text{ V }\!/\!\textit{c}$$ beam momenta measured by the NA61/SHINE spectrometer at the CERN SPS

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
A. Acharya ◽  
H. Adhikary ◽  
K. K. Allison ◽  
E. V. Andronov ◽  
T. Antićić ◽  
...  
Keyword(s):  
Particle Production ◽  
System Size ◽  
Hadronic Matter ◽  
Transverse Mass ◽  
Proton Synchrotron ◽  
Inverse Slope ◽  
Super Proton Synchrotron ◽  
Inverse Slope Parameter ◽  
The Mean ◽  
Momentum Transverse

AbstractThe physics goal of the strong interaction program of the NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) is to study the phase diagram of hadronic 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 differential inclusive spectra of transverse momentum, transverse mass and rapidity of $$\pi ^{-}$$ π -  mesons produced in central$${}^{40}$$ 40 Ar+$${}^{45}$$ 45 Sc collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150$$A\,\text{ Ge }\text{ V }\!/\!\textit{c}$$ A Ge V / c . Energy and system size dependence of parameters of these distributions – mean transverse mass, the inverse slope parameter of transverse mass spectra, width of the rapidity distribution and mean multiplicity – are presented and discussed. Furthermore, the dependence of the ratio of the mean number of produced pions to the mean number of wounded nucleons on the collision energy was derived. The results are compared to predictions of several models.

scholarly journals Status and plans of the ion program of NA61 at the CERN SPS

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Katarzyna Grebieszkow
Keyword(s):  
Phase Diagram ◽  
Critical Point ◽  
System Size ◽  
Hadron Production ◽  
Two Dimensional ◽  
Strongly Interacting ◽  
The Status ◽  
First Results ◽  
Onset Of Deconfinement

AbstractThe NA61/SHINE at the CERN SPS is a new experiment to study hadron production in p+p, p+A, h+A and A+A interactions. The main goal of the NA61 ion program is to explore the phase diagram (T − µB) of strongly interacting matter. In particular, we plan to study the properties of the onset of deconfinement and to search for the signatures of the critical point. A two-dimensional scan of the phase diagram will be performed by varying the energy (13A–158A GeV) and system size (p+p, Be+Be, Ar+Ca, Xe+La) of collisions. This paper summarizes the status and plans of the NA61/SHINE ion program. In particular the detector upgrades, data taking schedule and the first results on spectra and correlations are discussed.

scholarly journals Measurements of $$\pi ^-$$ production in $$^7$$Be + $$^9$$Be collisions at beam momenta from 19A to 150$$A\,\text{ GeV }\!/\!c$$ in the NA61/SHINE experiment at the CERN SPS

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
A. Acharya ◽  
H. Adhikary ◽  
A. Aduszkiewicz ◽  
K. K. Allison ◽  
E. V. Andronov ◽  
...  
Keyword(s):  
Particle Production ◽  
Nucleon Nucleon ◽  
Particle Identification ◽  
Hadronic Matter ◽  
Transverse Mass ◽  
Proton Synchrotron ◽  
Super Proton Synchrotron ◽  
The Mean ◽  
Onset Of Deconfinement ◽  
Formula Method

AbstractThe 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.

Single-muon rate reduction for beam dump operation of the K12 beam line at CERN

2019 ◽  
Vol 34 (36) ◽  
pp. 1942026
Author(s):  
M. Rosenthal ◽  
D. Banerjee ◽  
J. Bernhard ◽  
M. Brugger ◽  
N. Charitonidis ◽  
...  
Keyword(s):  
Beam Line ◽  
Proton Synchrotron ◽  
Particle Interactions ◽  
Dark Sector ◽  
Momentum Range ◽  
Super Proton Synchrotron ◽  
Beam Dump ◽  
Beryllium Target ◽  
Single Muon ◽  
Made In

The Physics Beyond Colliders study investigates the feasibility of future projects and experiments using CERN facilities. In the scope of this study, a future operation of the NA62 experiment using the existing K12 beam line operated in beam dump mode is discussed. Such a setup allows for a search for dark sector particles, e.g. heavy neutral leptons, dark photons and axions. Production of these hypothetical particles requires the 400GeV/c proton beam extracted from the Super Proton Synchrotron (SPS) to be dumped on a massive dump collimator located in the first part of the K12 beam line. The decay of these dark sector particles, for example, into muons could be detected by the NA62 experimental setup. However, muons created in particle interactions with material and from in-flight decays of secondary hadrons pose a critical background for this kind of experiment. Magnetic sweeping serves as an efficient tool for reducing this background. This paper discusses the simulation studies conducted with the software framework G4beamline to reduce the expected single-muon rate for this experiment. The required beam line modifications, in particular the removal of the beryllium target and repositioning of the dump, have been implemented into this model. A comparison of simulated muon distributions and spectra available experimental data, already taken in test runs, has been made in order to validate the beam line simulation. Finally, additional beam line modifications to further suppress the muon background are elaborated upon. These studies show a potential further reduction of a factor four of the total single-muon rate relative to the nominal setup over the full momentum range, and up to a factor twenty considering only muons with momenta [Formula: see text].

scholarly journals Searching for Minimum in Dependence of Squared Speed-of-Sound on Collision Energy

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Fu-Hu Liu ◽  
Li-Na Gao ◽  
Roy A. Lacey
Keyword(s):  
Speed Of Sound ◽  
Center Of Mass ◽  
Incident Beam ◽  
Gluon Plasma ◽  
Beam Momentum ◽  
Proton Synchrotron ◽  
Super Proton Synchrotron ◽  
Center Of Mass Energy ◽  
Knee Point ◽  
Charged Pions

Experimental results of the rapidity distributions of negatively charged pions produced in proton-proton (p-p) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parametercs2is then extracted from the width of rapidity distribution. There is a local minimum (knee point) which indicates a softest point in the equation of state (EoS) appearing at about40A GeV/c(or 8.8 GeV) incs2excitation function (the dependence ofcs2on incident beam momentum (or center-of-mass energy)). This knee point should be related to the searching for the onset of quark deconfinement and the critical point of quark-gluon plasma (QGP) phase transition.

scholarly journals Measurements of multiplicity fluctuations of identified hadrons in inelastic proton–proton interactions at the CERN Super Proton Synchrotron

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
A. Acharya ◽  
H. Adhikary ◽  
A. Aduszkiewicz ◽  
K. K. Allison ◽  
E. V. Andronov ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Data Analysis ◽  
Collision Energy ◽  
Beam Momentum ◽  
Particle Identification ◽  
Proton Synchrotron ◽  
Super Proton Synchrotron ◽  
Proton Proton ◽  
Intensive Quantities ◽  
Multiplicity Distributions

AbstractMeasurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158 $$\text {Ge}\text {V}/c$$ Ge / c beam momentum are presented. Three different measures of multiplicity fluctuations are used: the scaled variance $$\omega $$ ω and strongly intensive measures $$\Sigma $$ Σ and $$\Delta $$ Δ . 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.

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