• Browse all
Measurement of the $^3_{\Lambda}$H lifetime in Au+Au collisions at the BNL Relativistic Heavy Ion Collider

The collaboration
Phys.Rev.C 97 (2018) 054909, 2018.

Abstract
A precise measurement of the hypertriton lifetime is presented. In this letter, the mesonic decay modes $\mathrm{{^3_\Lambda}H \rightarrow ^3He + \pi^-}$ and $\mathrm{{^3_\Lambda}H \rightarrow d + p + \pi^-}$ are used to reconstruct the hypertriton from Au+Au collision data collected by the STAR collaboration at RHIC. A minimum $\chi^2$ estimation is used to determine the lifetime of $\tau = 142^{+24}_{-21}\,{\rm (stat.)} {\pm} 31\,{\rm (syst.)}$ ps. This lifetime is about 50\% shorter than the lifetime $\tau = 263\pm2$ ps of a free $\Lambda$, indicating strong hyperon-nucleon interaction in the hypernucleus system. The branching ratios of the mesonic decay channels are also determined to satisfy B.R.$_{(^3{\rm He}+\pi^-)}/$(B.R.$_{(^3{\rm He}+\pi^-)}+$B.R.$_{(d+p+\pi^-)})$ = $0.32\rm{\pm}0.05\,{\rm (stat.)}\pm 0.08\,{\rm (syst.)}$. Our ratio result favors the assignment $J(\mathrm{^{3}_{\Lambda}H})$ = $\frac{1}{2}$ over $J(\mathrm{^{3}_{\Lambda}H})$ = $\frac{3}{2}$. These measurements will help to constrain models of hyperon-baryon interactions.

• #### Table 1(a)

Data from Figure 2(a)

10.17182/hepdata.102407.v1/t1

The hypertriton yield as a function of ~l/βγ for each of the two analyzed decay channels. The redpoints are for...

• #### Table 1(b)

Data from Figure 2(a)

10.17182/hepdata.102407.v1/t2

The hypertriton yield as a function of l/βγ for each of the two analyzed decay channels. The bluesquares are for...

• #### Table 2(a)

Data from Figure 3

10.17182/hepdata.102407.v1/t3

A summary of worldwide $^3_{\Lambda}$H lifetime experimental measurements and theoretical calculations. The two star markers are the STAR collaboration’s measurement...

• #### Table 3(a)

Data from Figure 4

10.17182/hepdata.102407.v1/t4

A summary of worldwide $^3_{\Lambda}$H R_3 experimental measurements and theoretical calculations. The marker represents the present analysis. This Fig. summarizes...