High-precision measurement of the hypertriton mass

Abstract

In recent years, the high-precision technique of decay-pion spectroscopy at the Mainz Microtron (MAMI), using high-resolution magnetic spectrometers, contributed to the accurate determination of the Λ binding energy of 4 Λ H. For the lightest hypernucleus, the hypertriton, the binding energy is known only from measurements carried out with nuclear emulsions. An account is given on the potential of observing the hypertriton with decay-pion spectroscopy from fragmentation of light target nuclei. Statistical decay calculations suggest that lithium is the optimal target material to observe hypertriton decays under relative clean conditions with only few other light hyperfragments being produced. Finally, a high-precision measurement of the hypertriton mass at MAMI is proposed.

Recalibration of the binding energy of hypernuclei measured in emulsion experiments and its implications *

“…MeV [28], and cannot ensure the deviations of measured Q value for Λ decay and hypernuclear decay are in the same direction [28]. Recent precise measurements show that for p-shell hypernuclei, there is a discrepancy in the range of 0.4-0.8 MeV between early emulsion measurements and their measurements [39]. The authors of Ref.…”

“…The authors of Ref. [39] also argued that the emulsion data significantly underestimated the systematic error, which is dependent on the specific hypernucleus. Based on the above statement, we believe that the compensating effect described above may not fully account for the systematic error, and a recalibration of the Q 0 differences seems to be a more reliable method.…”

Decay pion spectroscopy: A new approach

“…. Statistical model predictions for the hyperfragmentaion yields from for 6,7 and 9 target nuclei, with subsequent two-body pionic decay at rest, are presented in Table 2 (for details see [13]).…”

“…Recently a new experiment was proposed at MAMI for the study of the binding energy of the Λ in the lightest hypernucleus: the hypertriton, which can reveal important details of the strong nucleon-hyperon interaction. In this experiment a new design of lithium target was considered to increase the rate of the detected hypernuclei by about an order of magnitude [13].…”

Precise Measurements of the Mass and the Binding Energy (\(B_{\Lambda }\)) of the Hypertriton at \(\sqrt{s_{NN}} = 200\) GeV with the Heavy Flavor Tracker at RHIC-STAR

“…Therefore, the 3 Λ H can serve as an excellent experimental way to explore the Y N interaction. Recent precise lifetime measurements of 3 Λ H had been carried out in heavy-ion collisions [7,12,13], but the most precise measurements of the mass were made about 40 years ago [14][15][16][17][18] and they may suffer from a large systematic uncertainty [18,19]. The STAR detector [20][21][22] (the Solenoidal Tracker at RHIC) located in Brookhaven National Laboratory provides us an ideal playground to precisely measure the masses of 3 Λ H and its antimatter partner 3 Λ H [10].…”