#
Charged Kaon Femtoscopy with Lévy Sources in $\sqrt{{s}_{\mathrm{NN}}}$ = 200 GeV Au+Au Collisions at PHENIX

## Abstract

**:**

## 1. Introduction

**P**ioneering

**H**igh

**E**nergy

**N**uclear

**I**nteraction e

**X**periment) detector. It is one of the four experiments that have taken data at the relativistic heavy ion collider (RHIC) in Brookhaven National Laboratory. Its primary mission was to search for a new state of matter called the quark–gluon plasma and to study various different particle types produced in heavy ion collisions, such as photons, electrons, muons, and charged hadrons. A beam view layout of the PHENIX detector can be seen in Figure 1. The detectors can be divided into four main subgroups:

- Global detectors characterize the nature of heavy ion collision events, i.e., zero degree calorimeters (ZDC) and beam-beam counters (BBC);
- Mid-rapidity detectors form the “central arm spectrometer”, which consists of three sets of pad chambers (PC), drift chambers (DC), electromagnetic calorimeters (EmCal), and time-of-flight detectors (ToF), are used for energy, momentum, and mass measurements;
- Two muon spectrometers at forward rapidity;
- A triggering and computing system to select and archive events of potential physics interest.

## 2. Femtoscopy and Lévy Sources

**q**instead of the four dimensional q vector:

## 3. Motivation

## 4. Measurement Details

**p**is the momentum. The distributions of ${m}^{2}$ were fitted mostly using single Gaussians; in cases of merging peaks, a double Gaussian was applied. To identify kaons, we applied a 2.5 standard deviation (${\sigma}_{\mathrm{p}}$) cut around the nominal kaon ${m}^{2}$ peak position and a 2.5${\sigma}_{\mathrm{p}}$ veto cut around the pion and proton ${m}^{2}$ peaks. An example scatter plot of the charge times momentum vs. ${m}^{2}$ before and after the cuts can be seen in Figure 2a,b, respectively.

## 5. Results

## 6. Conclusions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## Abbreviations

HBT | R. Hanbury Brown and R. Q. Twiss |

GGLP | G. Goldhaber, S. Goldhaber, W-Y. Lee, and A. Pais |

RHIC | Relativistic heavy ion collider |

LCMS | Longitudinal co-moving system |

PCMS | Pair co-moving system |

Au+Au | Gold–gold |

RMS | Root mean square |

## Note

1 | This variable can be expressed in the PCMS system, which is the pair rest frame: ${q}_{\mathrm{inv}}=\left|{\mathbf{q}}_{\mathrm{PCMS}}\right|$. |

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**Figure 1.**View of the PHENIX central arm spectrometer detector setup in the 2010 data-taking period.

**Figure 2.**Example plots for PID. (

**a**) Scatter plot of the charge times momentum vs. ${m}^{2}$ in TOF West with no cut. (

**b**) Scatter plot of the charge times momentum vs. ${m}^{2}$ in TOF West after the applied cuts.

**Figure 3.**An example fit with the Coulomb-corrected correlation function based on a Lévy source for kaon pairs with transverse mass ranging from 0.856 GeV/${c}^{2}$ to 0.940 GeV/${c}^{2}$.

**Figure 4.**Values of the $\alpha $ parameter in the case of pions and kaons. Boxes indicate the systematic uncertainties, while error bars are used to represent the statistical ones.

**Figure 5.**Values of the $\lambda $ parameter in the case of pions and kaons. Boxes indicate the systematic uncertainties, while error bars are used to represent the statistical ones.

**Figure 6.**Values of the R parameter in the case of pions and kaons. Boxes indicate the systematic uncertainties, while error bars are used to represent the statistical ones.

**Figure 7.**The transverse mass dependence of the 1/${R}^{2}$ points. It is worthwhile to note that due to the large uncertainties, one could fit these data points with different powers of ${m}_{\mathrm{T}}$ as well. A line is fitted to the data points, and the fitted parameters are shown in the legend. Boxes indicate the systematic uncertainties, while error bars are used to represent the statistical ones.

**Figure 8.**The transverse mass dependence of the 1/$\widehat{R}$ points. It is worthwhile to note that due to the large uncertainties, one could fit these data points with different powers of ${m}_{\mathrm{T}}$ as well. A line is fitted to the data points, and the fitted parameters are shown in the legend. Boxes indicate the systematic uncertainties, while error bars are used to represent the statistical ones.

Setting Name | Settings |
---|---|

PID cut | 3 cut settings |

PC3 matching cut | 1 cut setting |

EMCal/ToF matching cut | 3 cut settings |

DC pair cut | 3 cut settings |

ToF East pair cut | 3 cut settings |

ToF Wast pair cut | 3 cut settings |

EMCal pair cut | 3 cut settings |

Fit range (${Q}_{\mathrm{max}}$) | 3 ranges |

Fit range (${Q}_{\mathrm{min}}$) | 3 ranges |

Coulomb correction variable | 2 versions |

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**MDPI and ACS Style**

Kovács, L., on behalf of the PHENIX Collaboration.
Charged Kaon Femtoscopy with Lévy Sources in *Universe* **2023**, *9*, 336.
https://doi.org/10.3390/universe9070336

**AMA Style**

Kovács L on behalf of the PHENIX Collaboration.
Charged Kaon Femtoscopy with Lévy Sources in *Universe*. 2023; 9(7):336.
https://doi.org/10.3390/universe9070336

**Chicago/Turabian Style**

Kovács, László on behalf of the PHENIX Collaboration.
2023. "Charged Kaon Femtoscopy with Lévy Sources in *Universe* 9, no. 7: 336.
https://doi.org/10.3390/universe9070336