arXiv subjects

M. V. Purohit

Publications and source records attributed to M. V. Purohit.

6 recordsLinked to original sources

arXiv2013

Report of the Quark Flavor Physics Working Group

This report represents the response of the Intensity Frontier Quark Flavor Physics Working Group to the Snowmass charge. We summarize the current status of quark flavor physics and identify many exciting future opportunities for studying the properties of strange, charm, and bottom quarks. The ability of these studies to reveal the effects of new physics at high mass scales make them an essential ingredient in a well-balanced experimental particle physics program.

hep-ex↗

arXiv2012

Track Finding Efficiency in BaBar

We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BaBar detector. The first two studies measure the tracking efficiency of a charged particle using $τ$ and initial state radiation decays. The third uses the $τ$ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of $K_S^0$ particles. The first section also examines the stability of the measurements vs BaBar running periods.

hep-ex↗

arXiv2009

Renaissance of the ~1 TeV Fixed-Target Program

This document describes the physics potential of a new fixed-target program based on a ~1 TeV proton source. Two proton sources are potentially available in the future: the existing Tevatron at Fermilab, which can provide 800 GeV protons for fixed-target physics, and a possible upgrade to the SPS at CERN, called SPS+, which would produce 1 TeV protons on target. In this paper we use an example Tevatron fixed-target program to illustrate the high discovery potential possible in the charm and neutrino sectors. We highlight examples which are either unique to the program or difficult to accomplish at other venues.

hep-ex↗

arXiv2001

On the $D^0$ -- $D_s$ lifetime difference and $τ\to 7π+ ν_τ$ decays

In this paper we discuss some aspects of inclusive decays of charmed mesons and also decays of the $τ$ lepton into $ν_τ+ 7π$. We find that phase space effects are likely to explain the observed lifetime ratio $τ(D_s^+) / τ(D^0)$ = 1.17. In particular one need not appeal to a large annihilation contribution in the inclusive $D^0$ decay which, being absent in $D_s^+$ decays could also contribute to the enhanced $D^0$ decay rate relative to that of the $D_s^+$. Examining a separate problem, we find that the rate for $τ\to ν_τ+ 7π$ is almost completely dominated by the tiny phase space for the final eight particle state. Using an effective chiral Lagrangian to estimate the matrix element yields a branching ratio into the channel of interest far smaller than the present upper bound.

hep-ph↗

arXiv2000

Light meson and baryon spectroscopy from charm decays in Fermilab E791

We present results from Fermilab experiment E791. We extracted the fractions of resonant components in the $Λ_c^+\to p K^- π^+$ decays, and found a significant polarization of the $Λ_c^+$ using a fully 5-dimensional resonant analysis. We also did resonant analyses of $D^+$ and $D^+_s$ decays into $π^+π^-π^+$. We observed an insignificant asymmetry in the Breit Wigner describing the $f_0(980)$ and found good evidence for a light and broad scalar resonance in the $D^+$ decays.

hep-ex↗

arXiv1996

Asymmetries between the production of D+ and D- mesons from 500 GeV/c pi- nucleon interactions as a function of xF and pt**2

We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used.

hep-ex↗