arXiv subjects

A. S. Fomin

Publications and source records attributed to A. S. Fomin.

4 recordsLinked to original sources

arXiv2019

The prospect of charm quark magnetic moment determination

In this paper, we discuss the theoretical framework and the experimental measurements of the magnetic moment of the charm baryons. The $Λ_c^+$ magnetic moment is particularly interesting since it is equal to the magnetic moment of the charm quark. The measurements of the magnetic moments of other charm baryons, such as $Ξ_c$, allow to perform detailed spectroscopy studies. The magnetic moment of the $Λ_c$ can be determined using radiative charmonium decay and the present results show a tension with majority of theoretical predictions. As recently pointed out, the magnetic moment of the charm baryons can be directly measured using bent-crystal experiments at LHC. The possibility of precisely measure the magnetic moments of charm baryons needs precise measurement of their polarisation and weak decay parameters. In this paper, we revisit the formalism of the angular analysis needed for these measurements and make a detailed evaluation of initial polarisation of deflected $Λ_c$ baryons as a function of crystal orientation. We found a special orientation of the crystal that gives the opportunity to measure the $Λ_c$ dimensionless electric dipole moment almost with the same precision as its $g$-factor, which is more than an order of magnitude more efficient than suggested before. In conclusion, we stress the importance to perform precise measurements of initial polarisation and weak decay parameters of $Λ_c$ baryon to effectively compare the direct and from decay measurements of magnetic moments.

hep-ph↗

arXiv2019

Layouts for fixed-target experiments and dipole moment measurements of short-living baryons using bent crystals at the LHC

Several studies are on-going at CERN in the framework of the Physics Beyond Collider study group, with main aim of broadening the physics research spectrum using the available accelerator complex and infrastructure. The possibility to design a layout that allows fixed-target experiments in the primary vacuum of the CERN Large Hadron Collider (LHC), without the need of a dedicated extraction line, is included among these studies. The principle of the layouts presented in this paper is to deflect beam halo protons on a fixed-target placed in the LHC primary vacuum, by means of bent crystals (i.e. crystal channeling). Moreover, interaction products emerging from the target can be used to perform electromagnetic dipole moments measurements of short-living baryons. Two possible layouts are reported, together with a thorough evaluation on their expected performance and impact on LHC operations.

physics.acc-ph↗

arXiv2019

Feasibility of tau lepton electromagnetic dipole moments measurement using bent crystal at the LHC

In this paper we discuss the possibility of measuring the anomalous magnetic and electric dipole moments of the $τ$ lepton. The method consists in studying the spin precession induced by the strong effective magnetic field inside channels of a bent crystal with a dedicated setup at the CERN Large Hadron Collider.

hep-ph↗

arXiv2017

Feasibility of measuring the magnetic dipole moments of the charm baryons at the LHC using bent crystals

In this paper we revisit the idea of measuring the magnetic dipole moments of the charm baryons and, in particular, of charmed Lambda by studying the spin precession induced by the strong effective magnetic field inside the channels of a bent crystal. We present a detailed sensitivity study showing the feasibility of such an experiment at the LHC in the coming years.

hep-ph↗