BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Status of WASA-FRS HypHI Experiment: Study of light hypernuclei at
  GSI-FAIR
DTSTART;VALUE=DATE-TIME:20241119T143000Z
DTEND;VALUE=DATE-TIME:20241119T144500Z
DTSTAMP;VALUE=DATE-TIME:20260421T082705Z
UID:indico-contribution-25489@indico.ific.uv.es
DESCRIPTION:Speakers: Samuel Escrig López (Instituto de Estructura de la 
 Materia (IEM-CSIC))\nThe WASA-FRS HypHI Experiment focuses on the study of
  light hypernuclei by means of heavy-ion induced reactions. It is part of 
 the WASA-FRS experimental campaign\, and so is the Eta-prime Experiment [1
 ]. The distinctive combination of the high-resolution spectrometer FRS [2]
  and the high-acceptance detector system WASA [3] is used. The experiment 
 was successfully conducted at GSI-FAIR in Germany in March 2022 as a compo
 nent of the FAIR Phase-0 Physics Program\, within the Super-FRS Experiment
  Collaboration. Currently\, the data from the experiment is under analysis
 .\n\nIn this experiment\, the production of the hypernuclei is achieved by
  bombarding a diamond target with a 6Li beam at 1.96 GeV/u. In this collis
 ion\, Λ hyperon can merge with the nuclear fragment\, forming a hypernucl
 eus. The production of hypernuclei in the spectator rapidity region\, with
  a similar velocity of the incident beam\, allows for the in-flight study 
 of the hypernuclei behind the target material. The hypernuclear events are
  identified by detecting both the residual nuclei and the π- particles em
 itted from the mesonic weak decay of the hypernuclei.\n\nThe second half o
 f the FRagment Separator FRS serves as a high-resolution spectrometer for 
 measuring the decay fragments. Additionally\, the Wide Angle Shower Appara
 tus (WASA)\, placed in the mid-focal plane of the FRS\, is employed for tr
 acking the decay π- particle. The WASA system consists of a superconducti
 ng magnet and a group of detectors\, including a drift chamber of several 
 layers of strawtubes and plastic scintillator barrel and walls. The hypern
 ucleus is subsequently reconstructed\, and its properties\, such as invari
 ant mass and lifetime\, are analysed.\n\nThe primary objectives of this ex
 periment are twofold: to shed light on the hypertriton puzzle [4] and to i
 nvestigate the existence of the previously proposed nnΛ bound state [5]. 
 Firstly\, the significantly shorter hypertriton lifetime reported by three
  independent state-of-the-art experiments\, namely ALICE [6]\, STAR [7]\, 
 and HypHI [8]\, compared to the predictions of theoretical models remains 
 poorly understood. Therefore\, obtaining new accurate results for the inva
 riant mass and lifetime of 3ΛH (and 4ΛH) is crucial to reach a definitiv
 e conclusion. Secondly\, the observed enhancement in the invariant mass di
 stributions of the d+π- and t+π- final states\, as reported by the HypHI
  Collaboration [5]\, cannot be accounted for by existing theoretical calcu
 lations\, which indicate the absence of a neutral nnΛ bound state. Conseq
 uently\, the WASA-FRS HypHI Experiment aims to produce more precise and st
 atistically significant experimental results that can provide clarificatio
 n on the potential existence of nnΛ.\n\nMy contribution to the conference
  will provide an overview of the WASA-FRS HypHI Experiment\, including its
  objectives and methodology. Details of the experiment approach that combi
 nes for the first time a cylindrical detection system with a fragment sepa
 rator will be presented. I will also discuss the current state of the expe
 riment analysis\, emphasizing the GNN implementation for particle tracking
  and the ion-optics calibration. Finally\, I will show the first prelimina
 ry results of the invariant mass of Λ and 3ΛH.\n\n[1] Y.K. Tanaka *et al
 .*\, J. Phys. Conf. Ser. **1643** (2020) 012181.\n[2] H. Geissel *et al.*\
 , Nucl. Instr. and Meth. B **70** (1992) 286-297.\n[3] C. Bargholtz *et al
 .*\, Nucl. Instr. and Meth. A **594** (2008) 339-350.\n[4] T.R. Saito *et 
 al.*\, Nature Reviews Physics **3** (2021) 803-813.\n[5] C. Rappold *et al
 .*\, Phys. Rev. C **88** (2013) 041001.\n[6] S. Acharya *et al.*\, Phys. L
 ett. B **797** (2019) 134905.\n[7] L. Adamczyk *et al.*\, Phys. Rev. C **9
 7** (2018) 054909.\n[8] C. Rappold *et al.*\, Nucl. Phys. A **913** (2013)
  170-184.\n\nhttps://indico.ific.uv.es/event/7664/contributions/25489/
LOCATION:
URL:https://indico.ific.uv.es/event/7664/contributions/25489/
END:VEVENT
END:VCALENDAR