Polarization of a top quark produced in the decay of a gluino or a stop in an arbitrary frame

Arunprasath, V and Godbole, Rohini M and Singh, Ritesh K (2017) Polarization of a top quark produced in the decay of a gluino or a stop in an arbitrary frame. In: PHYSICAL REVIEW D, 95 (7).

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Abstract

We show that for values of masses of the gluino and stop favored by ``naturalness,'' the top quark produced in the decay (g) over tilde -> t (t) over tilde (1) can be polarized. This polarization depends only on the mixing in the stop sector as opposed to that of the top quark produced in decays (t) over tilde -> t (chi) over tilde (0)(i), (b) over tilde -> t (chi) over tilde (-)(i). In both the cases the polarization constructed through the distribution of top decay products in the laboratory frame, is different from the top polarization predicted in the rest frame of the mother particle (gluino/stop), which depends on the SUSY parameters as mentioned above. Here, we propose an estimator of lab frame top quark polarization, starting from the rest frame polarization of the top. This estimator depends only on the magnitude of velocity of the mother particle and assumes a narrow width for the mother particle. With a Monte-Carlo simulation of the full production and decay chain we establish our estimator to be accurate within 1% and the computation is a much simpler exercise compared to calculating from first principle. We also study effects of finite width of the mother particle using a suitably modified estimator and find it most useful for stop-quarks decays.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW D
Additional Information:	Copy right for this article belongs to the AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	25 May 2017 09:54
Last Modified:	25 May 2017 09:54
URI:	http://eprints.iisc.ac.in/id/eprint/57057

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