Study of Charge Symmetry Breaking in A = 4 hypernuclei in √SNN = 3 GeV Au+Au collisions at RHIC

Tianhao Shao,G David,S Mukherjee,P Garg,T Ullrich,Z Xu,I.-K Yoo,A Kalweit

doi:10.1051/epjconf/202225913003

Tianhao Shao, G David + Show 6 more

Open Access

https://doi.org/10.1051/epjconf/202225913003

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Abstract

In this paper, we present the measurement of the charge symmetry breaking in A = 4 hypernuclei in Au+Au collisions at √SNN = 3 GeV. The signal reconstruction and binding energy measurement of Λ4H and Λ4He, including corrections and systematic uncertainty evaluation, are discussed. Combined with the energy levels of excited states, our preliminary result of Λ binding energy difference for excited states is ΔBΛ(1+) = −190±130(stat.)±70(syst.) keV which shows a negative value and its magnitude is comparable to the result of ground states ΔBΛ(0+) = 130 ± 130(stat.) ± 70(syst.) keV. These results are compared with previous measurements and theoretical model calculations.

Highlights

The charge symmetry of strong interactions predicts that the Λ-p and Λ-n interactions should be identical as they cannot be influenced by charge
The E13 collaboration combined the Λ binding energies of ground states from emulsion experiments of 1970s [1] with a γ-ray transition energy for 4ΛH measured in 1976 [3] and their new γ-ray transition measurement for 4ΛHe to determine the difference in excited states to be ∆B4Λ(1+exc) = 30 ± 50 keV [2] which is much smaller than that in ground states
Gazda and Gal reported a large splitting in ground states and a large value in excited states with an opposite sign and a similar magnitude, ∆B4Λ(1+exc) ≈ −∆B4Λ(0+g.s.) < 0 [10], which is slightly favored by our preliminary results

Summary

Introduction

The charge symmetry of strong interactions predicts that the Λ-p and Λ-n interactions should be identical as they cannot be influenced by charge. In 2015, the J-PARC E13 γ-ray spectroscopy experiment measured the transition energy from the 1+ first excited state of 4ΛHe to be 1406 ± 2 ± 2 keV [2]. The E13 collaboration combined the Λ binding energies of ground states from emulsion experiments of 1970s [1] with a γ-ray transition energy for 4ΛH measured in 1976 [3] and their new γ-ray transition measurement for 4ΛHe to determine the difference in excited states to be ∆B4Λ(1+exc) = 30 ± 50 keV [2] which is much smaller than that in ground states. In 2016, the MAMI A1 collaboration used spectrometers to provide a new measurement of the ground state Λ binding energy of 4ΛH [4]. STAR fixed target program gives us an opportunity to study the binding energy of

Analysis details and results

Conclusions