XXV DAE-BRNS High Energy Physics Symposium 2022

Newly observed $B_{sJ}(6063)$ and $B_{sJ}(6114)$ mesons in HQET

16 Dec 2022, 14:00

1h

LHC Foyer (IISER Mohali)

Poster Poster - 4

Speakers

Keval Gandhi (Department of Computer Sciences and Engineering, Institute of Advanced Research, Gandhinagar 382426, INDIA)Mrs Pooja Jakhad (Department of Physics, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat 395007, INDIA)Ms Juhi Oudichhya (Department of Physics, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat 395007, INDIA)Dr Ajay Kumar Rai (Department of Physics, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat 395007, INDIA)

Description

Over the past ten years, the evidence for charmed mesons has increased rapidly and remarkably in comparison to the bottom mesons [1]. In the bottom sector, however, it is challenging to identify the broad resonance states because of large non-resonant continuum contributions. To date, the experimental groups have confirmed only ground and low-lying excited states of bottom mesons [2-4]. In the upcoming years, we hope that more experimental data may be published. The CERN-based LHCb experiment will be in a unique position for this.

Recently, the LHCb [5] measured the masses $(M)$ and decay widths ($\Gamma$) of two new states of excited $B_s$ mesons into $BK$ decay mode as

$B_{sJ}(6063)$: $(M, \Gamma) = (6063.5 \pm 1.2 \pm 0.8, 26 \pm 4 \pm 4)$ MeV,
$B_{sJ}(6114)$: $(M, \Gamma) = (6114 \pm 3 \pm 5, 66 \pm 18 \pm 21)$ MeV,

considering the first statistical and second systematic uncertainty. Theories and phenomenological studies for the masses of excited $B_s$ mesons suggest that these recently discovered states could be the first orbitally excited states [6-8]. Now is a good time to do a detailed theoretical analysis of excited bottom mesons.

Motivated by the recent observation of the orbital excitation $B_{sJ}(6063)$ and $B_{sJ}(6114)$ by the LHCb Collaboration [5], we have carried out a systematic study of the excited $B_s$ mesons in a framework of heavy quark effective theory (HQET). Using the spin-flavor symmetry of the heavy-quark and chiral symmetry of the light quark, we explore the flavor independent parameters $\Delta_F^{(c)} = \Delta_F^{(b)}$ and $\lambda_F^{(c)} = \lambda_F^{(b)}$ to calculate the masses of experimentally unknown bottom mesons [9]. Moreover, their strong decay behavior to the ground state bottom mesons plus light pseudoscalar mesons is determined [10, 11]. We believe that the present study will not only shed light on the properties of these observed bottom mesons, but will also provide useful clues for future experimental research of the radially and orbitally excited states.

References:

[1] P.A. Zyla et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2020.8 (2020), p. 083C01.
[2] R. Aaij et al. (LHCb Collaboration), JHEP 2015.4 (2015), p. 1.
[3] R. Aaij et al. (LHCb Collaboration), Phys. Rev. lett. 110.15 (2013), p. 151803.
[4] T. Aaltonen et al. (CDF Collaboration), Phys. Rev. D 90.1 (2014), p. 012013.
[5] R. Aaij et al. (LHCb Collaboration), Eur. Phys. J. C 81.7 (2021), p. 601.
[6] D. Ebert, R. Faustov and V. Galkin, Eur. Phys. J. C 66.1 (2010), p.197.
[7] N. Devlani, A.K. Rai, Eur. Phys. J. A 48.7 (2012) p. 104.
[8] V. Kher, N. Devlani, A.K. Rai, Chin. Phys. C 41.9 (2017), p. 093101.
[9] P. Colangelo, F De. Fazio, F. Giannuzzi, S. Nicotri, Phys. Rev. D 86.5 (2012), p. 054024.
[10] K. Gandhi, A.K. Rai, Eur. Phys. J. C 82.9 (2022), p. 777.
[11] K. Gandhi, A.K. Rai, Eur. Phys. J. A 57.1 (2021), p. 23.