# Looking for the Phase Transition—Recent NA61/SHINE Results

^{†}

## Abstract

**:**

## 1. Introduction

**S**uper Proton Synchrotron (SPS)

**H**eavy

**I**on and

**N**eutrino

**E**xperiment, is a continuation and extension of the NA49 experiment [1,2]. It uses a similar experimental fixed-target setup to NA49 (Figure 1) but with an extended research programme. Beyond an enhanced strong interactions programme, measurements of hadron production for neutrino and cosmic ray experiments are realized. The collaboration involves about 150 physicists from 15 countries and 30 institutions. It is the second largest non-LHC (the Large Hadron Collider) experiment at the CERN.

## 2. New NA61/SHINE Results

#### 2.1. Irregularities—The Horn

#### 2.2. Irregularities—The Step

#### 2.3. Fluctuations

## 3. System Size Dependence

## 4. Conclusions

## Acknowledgments

## Conflicts of Interest

## Abbreviations

AGS | Argonne National Laboratory |

CERN | Conseil Europén pour la Recherche Nucléaire |

CR | critical point |

HG | hadron gas |

J-PARC | Japan Proton Accelerator Research Complex |

LHC | Large Hadron Collider |

HIC | heavy ion collision |

QCD | quantum chromodynamics |

QGP | quark-gluon plasma |

RHIC | Relativistic Heavy Ion Collider |

SPS | Super Proton Synchrotron |

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**Figure 1.**The NA61/SHINE detector consists of a large acceptance hadron spectrometer followed by a set of six Time Projection Chambers (TPCs) as well as Time-of-Flight detectors (ToFs). The high resolution forward calorimeter, the Projectile Spectator Detector (PSD), measures energy flow around the beam direction. For hadron-nucleus interactions, the collision volume is determined by counting low momentum particles emitted from the nuclear target with the Low Momentum Particle Detector (a small TPC) surrounding the target. An array of beam detectors identifies beam particles, secondary hadrons and nuclei as well as primary nuclei, and measures their trajectories precisely.

**Figure 2.**For the programme on strong interactions, NA61/SHINE scans in the system size and beam momentum. In the plot, the recorded data are indicated in green, the approved future data in red, and the proposed extension for the period ⩾2018 is in grey.

**Figure 3.**Phase diagram of strongly interacting matter in the temperature and baryonic chemical potential $(T,{\mu}_{B})$ plane. Picture taken from this (CSQCD 2017) conference poster.

**Figure 4.**(

**a**) Sketch of a possible quantum chromodynamic (QCD)-phase diagram with the commonly accepted standard evolution path of the universe as calculated e.g., in [18]. (

**b**) Sketch of a possible QCD phase diagram with the evolution path in the scenario of the cosmic separation of phases.

**Figure 5.**Horn: a strong maximum of the ratio of ${K}^{+}/{\pi}^{+}$ multiplicities. A reduced shadow of the horn structure is visible in p+p reactions.

**Figure 6.**Inverse slope parameters T of negative (

**a**) and positive (

**b**) kaons exhibit rapid changes in the SPS energy range—also seen in p+p collision. Data collected from all available energy ranges (

**c**).

**Figure 7.**Critical fluctuations in ${p}_{T}$ of negative (

**a**) and positive (

**b**) charged hadrons in

^{40}Ar +

^{45}Sc,

^{7}Be +

^{9}Be and p+p collisions.

**Figure 8.**

**(a)**multiplicity fluctuation increases with collision energy in Be+Be but remains constant in Ar+Sc. (

**b**) multiplicity fluctuation in Ar + Sc,

^{7}Be +

^{9}Be and p+p collisions. Be+Be almost identical to p+p fluctuation within statistical errors given by plot’s points sizes.

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**MDPI and ACS Style**

Turko, L.
Looking for the Phase Transition—Recent NA61/SHINE Results. *Universe* **2018**, *4*, 52.
https://doi.org/10.3390/universe4030052

**AMA Style**

Turko L.
Looking for the Phase Transition—Recent NA61/SHINE Results. *Universe*. 2018; 4(3):52.
https://doi.org/10.3390/universe4030052

**Chicago/Turabian Style**

Turko, Ludwik.
2018. "Looking for the Phase Transition—Recent NA61/SHINE Results" *Universe* 4, no. 3: 52.
https://doi.org/10.3390/universe4030052