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Measurement of the H Λ3 lifetime in Au+Au collisions at the BNL Relativistic Heavy Ion Collider

  • Author(s): Adamczyk, L;
  • Adams, JR;
  • Adkins, JK;
  • Agakishiev, G;
  • Aggarwal, MM;
  • Ahammed, Z;
  • Ajitanand, NN;
  • Alekseev, I;
  • Alford, J;
  • Anderson, DM;
  • Aoyama, R;
  • Aparin, A;
  • Arkhipkin, D;
  • Aschenauer, EC;
  • Ashraf, MU;
  • Attri, A;
  • Averichev, GS;
  • Bai, X;
  • Bairathi, V;
  • Barish, K;
  • Behera, A;
  • Bellwied, R;
  • Bhasin, A;
  • Bhati, AK;
  • Bhattarai, P;
  • Bielcik, J;
  • Bielcikova, J;
  • Bland, LC;
  • Bordyuzhin, IG;
  • Bouchet, J;
  • Brandenburg, JD;
  • Brandin, AV;
  • Brown, D;
  • Bryslawskyj, J;
  • Bunzarov, I;
  • Butterworth, J;
  • Caines, H;
  • Calderón De La Barca Sánchez, M;
  • Campbell, JM;
  • Cebra, D;
  • Chakaberia, I;
  • Chaloupka, P;
  • Chang, Z;
  • Chankova-Bunzarova, N;
  • Chatterjee, A;
  • Chattopadhyay, S;
  • Chen, X;
  • Chen, X;
  • Chen, JH;
  • Cheng, J;
  • Cherney, M;
  • Christie, W;
  • Contin, G;
  • Crawford, HJ;
  • Das, S;
  • Dedovich, TG;
  • Deng, J;
  • Deppner, IM;
  • Derevschikov, AA;
  • Didenko, L;
  • Dilks, C;
  • Dong, X;
  • Drachenberg, JL;
  • Draper, JE;
  • Dunlop, JC;
  • Efimov, LG;
  • Elsey, N;
  • Engelage, J;
  • Eppley, G;
  • Esha, R;
  • Esumi, S;
  • Evdokimov, O;
  • Ewigleben, J;
  • Eyser, O;
  • Fatemi, R;
  • Fazio, S;
  • Federic, P;
  • Federicova, P;
  • Fedorisin, J;
  • Feng, Z;
  • Filip, P;
  • Finch, E;
  • Fisyak, Y;
  • Flores, CE;
  • Fujita, J;
  • Fulek, L;
  • Gagliardi, CA;
  • Geurts, F;
  • Gibson, A;
  • Girard, M;
  • Grosnick, D;
  • Gunarathne, DS;
  • Guo, Y;
  • Gupta, A;
  • Guryn, W;
  • Hamad, AI;
  • Hamed, A;
  • Harlenderova, A;
  • Harris, JW;
  • He, L
  • et al.
Abstract

An improved measurement of the HΛ3 lifetime is presented. In this paper, the mesonic decay modes HΛ3→He3 + π- and HΛ3→d+p+π- are used to reconstruct the HΛ3 from Au+Au collision data collected by the STAR collaboration at Relativistic Heavy Ion Collider (RHIC). A minimum χ2 estimation is used to determine the lifetime of τ=142-21+24(stat.)±29(syst.) ps. This lifetime is about 50% shorter than the lifetime τ=263±2 ps of a free Λ, indicating strong hyperon-nucleon interaction in the hypernucleus system. The branching ratios of the mesonic decay channels are also determined to satisfy B.R.(He3+π-)/(B.R.(He3+π-)+B.R.(d+p+π-))=0.32±0.05(stat.)±0.08(syst.). Our ratio result favors the assignment J(HΛ3)=12 over J(HΛ3)=32. These measurements will help to constrain models of hyperon-baryon interactions.

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