3-10 August 2016
Chicago IL USA
US/Central timezone
There is a live webcast for this event.

Exploring the Masses of Exotic Heavy Pentaquarks

Aug 6, 2016, 6:00 PM
2h
Riverwalk A/B

Riverwalk A/B

Poster Strong Interactions and Hadron Physics Poster Session

Speaker

Dr Ballari Chakrabarti (Jogamaya Devi College, Kolkata, India)

Description

After the recent discovery of charmed pentaquarks $P_c^*$ (4380) and, $P_c^*$ (4450) [1] quick search has been set in for other pentaquarks. In the present work, the masses of the cryptoexotic pentaquarks with hidden beauty $P_b^*$ ($uudb\bar{b}$), and strangeness $P_s^*$ ($uuds\bar{s}$) have been estimated considering a di-hadronic state consisting of a meson and a baryon. In addition to this, other exotic heavy pentaquarks such as, $\Theta_c^0$($uudd\bar{c}$), $\Theta_b^{+}$($uudd\bar{b}$), $\Theta_{cs}^{++}$ ($cuud\bar{s})$, $\Theta_{bs}^{+}$ ($buud\bar{s}$) and related family members have been probed. The results agree well with the existing literature [2]. The interaction between the meson and the baryon, i.e., the residual interaction of the confined gluons has been taken to be Van der Waals’ type of molecular interaction $V(r_{12})=-(K_{mol}/r_{12})\exp(-c^2 r_{12}^2/2)$ , where, $K_{mol}$ is the residual strength of the strong interaction molecular coupling, $c$ is the effective color screening of the confined gluons. The mass formula for calculating the heavy pentaquark masses now stands out to be, \begin{equation} M_ {pentaquark} = M_{meson} + M_{baryon} + E_{BE}+ E_{SD} \end{equation} Here, $E_{BE}$ and $E_{SD}$ represent the binding energy and the hyperfine spin interaction of the system, which are being estimated in the present work following the prescription of a statistical model, and are given by, $ E_{BE} = \frac{2.25 K_{mol}}{r_{12}} \left [_{2}F_2(1.5,1.0),(2.75,2.25), -\beta \right ] $, with $\beta=c^2r_{12}^2/2$, and Re$\beta >0$, and $ E_{SD} = \frac{8}{9} \frac{\alpha_s}{M_{meson} M_{baryon}} (\vec{S_1}.\vec{S_2}) |\psi_0|^2 $. Here, $\alpha_s$ is the strong interaction constant, taken to be equal to 0.59. $K_{mol}=0.65$, and $c=50$ MeV [3]. The masses of the cryptoexotic pentaquarks, as estimated in our calculation, are given for $P_b^*$(1) , $P_b^*$(2) , $P_s^*$(1) , and $P_s^*$(2) are 10.638, 10.881, 2.110, and 2.381 GeV respectively. The masses of $\Theta_c^0$ , $N_c^0$ , $\Xi_c^0$ , $\Theta_{cs}^{++}$, $\Theta_b^+$, $N_b^+$, $\Xi_b^+$, and $\Theta_{bs}^+$ have been estimated as, 2.656, 2.752, 2.905, 2.752, 6.043, 6.127, 6.366, and 6.128 GeV respectively. The reported values for the masses of these exotic pentaquarks may inspire furute experiments. References: [1] R. Aaij et al, (LHCb Collab.), Phys. Rev. Lett. 115 (2015), 072001. [2] D. Diakonov, arXiv hep-ph/1003.2157; V. Kopeliovich et al, arXiv hep-ph/1510.05958; R. Jaffe et al, Phys. Rev. Lett. 91 (2003), 232003; M. Karliner et al, arXiv hep-ph/1030.7343. [3] B. Chakrabarti et al, Phys. Scr. 79 (2009), 025103.

Primary author

Dr Ballari Chakrabarti (Jogamaya Devi College, Kolkata, India)

Presentation materials