A global analysis of charmless two body hadronic decays for anti-triplet charmed baryons

Abstract

Recently Belle collaboration reported new measurements for the branching fractions with the first observing two processes of $$ \mathcal{B}\left({\Xi}_c^0\to \Lambda {K}_S^0\right) $$ B Ξ c 0 → Λ K S 0 , $$ \mathcal{B}\left({\Xi}_c^0\to {\Sigma}^0{K}_S^0\right) $$ B Ξ c 0 → Σ 0 K S 0 and updating data for $$ \mathcal{B}\left({\Xi}_c^0\to {\Sigma}^{+}{K}^{-}\right) $$ B Ξ c 0 → Σ + K − . Combined with other known data on charmless two body decays of anti-triplet charmed baryons, a lot of information can be derived with the assistance of SU(3) flavour symmetry. Using SU(3) relations between different decay modes, we can give some predictions based on the new measurements which can be tested with the high luminosity experiments in the future. More interestingly, we find that a global fit is now possible with the addition of new Belle data. In general, there are 18 complex SU(3) invariant amplitudes. We find that a scenario of all amplitudes being real can fit the data well with a χ2/d.o.f. only 0.773. This indicates that neglecting the phases of the amplitudes is a reasonable assumption. When more data become available, one may be able to get more information for phases in the amplitudes. We give several comments on the feature of global fit regarding the branching fractions, relations between different decays, and decays involving K0 and $$ \overline{K} $$ K ¯ 0. Many of the unknown branching fractions and polarization asymmetry parameters of anti-triplet charmed baryon for charmless two body decays are predicted to be accessible by experiments at Belle, Belle II, BES-III, and LHCb. The validity of SU(3) for charmless two body hadronic decays can be more accurately tested.

Measurement of Branching Fractions of Singly Cabibbo-suppressed Decays $Λ_c^+ \rightarrow Σ^{0} K^+$ and $Σ^{+} K_{S}^0$

“…Furthermore, improved measurements may clarify the tension between the predictions in Ref. [6] and Refs. [2][3][4][5].…”

“…The study of charmed baryon decays is valuable for both understanding charmed-baryon dynamics and probing the effects of the weak and strong interactions. Since the ground state of the charmed baryons Λ + c was discovered [1], many efforts have been made to predict its branching fractions (BFs) into two-body hadronic final states, Λ + c → B n M [2][3][4][5][6][7], where B n and M denote the octet baryon and nonet meson states, respectively. However, progress has been hindered, due to the limited precision of experimental measurements [8] and difficulties in the theoretical treatment of non-perturbative strong interaction effects.…”

“…In addition, the BESIII, LHCb and Belle collaborations have carried out complementary analyses of charmed baryons, such as lifetime measurements [17][18][19][20][21] and studies of semi-leptonic decays [22][23][24][25][26]. Improved measurements of the BFs of the Λ c decays can provide crucial inputs for the theoretical models [3][4][5][6], in particular those of the SCS Λ c → ΣK decays for which there exists very limited experimental information.…”

“…In Ref. [6], the irreducible representation amplitude (IRA) approach is used to extract amplitudes from experimental data inputs, which gives quite different predictions for B(Λ + c → Σ 0 K + ) and B(Λ + c → Σ + K 0 S ). In particular, Ref.…”

“…Those predictions in Refs. [4][5][6] are from fits that take an ensemble of measured BFs as inputs, and are limited by the precision of these measurements. Thus, new determinations of the BFs of Λ c → ΣK decays, in particular the mode Λ + c → Σ + K 0 S , are important for validating and improving these theoretical-model calculations.…”