arXiv subjects

A. Asratyan

Publications and source records attributed to A. Asratyan.

7 recordsLinked to original sources

arXiv2015

The transverse momentum dependence of charged kaon Bose-Einstein correlations in the SELEX experiment

We report on the measurement of the one-dimensional charged kaon correlation functions using 600~GeV/{\it c} $Σ^-$, $π^-$ and 540~GeV/{\it c} $p$ beams from the SELEX~(E781) experiment at the Fermilab Tevatron. $K^{\pm}K^{\pm}$ correlation functions are studied for three transverse pair momentum, $k_T$, ranges and parameterized by a Gaussian form. The emission source radii, $R$, and the correlation strength, $λ$, are extracted. The analysis shows a decrease of the source radii with increasing kaon transverse pair momentum for all beam types.

hep-ex↗

arXiv2010

A New Measurement of the $π^0$ Radiative Decay Width

High precision measurements of the differential cross sections for $π^0$ photoproduction at forward angles for two nuclei, $^{12}$C and $^{208}$Pb, have been performed for incident photon energies of 4.9 - 5.5 GeV to extract the ${π^0 \to γγ}$ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The ${π^0 \to γγ}$ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is $Γ{(π^0 \to γγ)} = 7.82 \pm 0.14 ~({\rm stat.}) \pm 0.17 ~({\rm syst.}) ~{\rm eV}$. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current PDG average of this fundamental quantity and it is consistent with current theoretical predictions.

nucl-ex↗

arXiv2008

Nuclear Targets for a Precision Measurement of the Neutral Pion Radiative Width

A technique is presented for precision measurements of the area densities, density * T, of approximately 5% radiation length carbon and 208Pb targets used in an experiment at Jefferson Laboratory to measure the neutral pion radiative width. The precision obtained in the area density for the carbon target is +/- 0.050%, and that obtained for the lead target through an x-ray attenuation technique is +/- 0.43%.

nucl-ex↗

arXiv2003

Neutrino Superbeams and the Magic Baseline

We examine the sensitivity to ν_μ--> ν_e of a conceptual neutrino experiment that involves a neutrino superbeam, a Megaton-scale water Cherekov detector, and a "magic" baseline ~7300 km. With realistic beam intensity and exposure time, the mixing parameter sin^2 2θ_{13} and the sign of "atmospheric" mass-squared difference may be unambiguously probed down to sin^2 22θ_{13} values below 10^{-3}.

hep-ex↗

arXiv2003

Multi-ring signatures of the oscillation nu_mu --> nu_e in a water Cherenkov detector

Multiring signatures of the oscillation nu_mu --> nu_e are formulated for a water Cherenkov detector. These are appropriate for relatively high neutrino energies (over 2 GeV) that emphasize the matter effect and, therefore, may allow to measure the sign of the atmospheric mass-squared difference.

hep-ex↗

arXiv2002

A non-QE signature of nu_e appearance in a water Cherenkov detector

We argue that analyzing the nu_e- and bar{nu_e}-induced CC reactions nu_e n --> e^- pi^0 p and bar{nu}_e p --> e^+ pi^0 n along with quasielastics may significantly enhance the sensitivity of a water Cherenkov detector to subleading oscillations nu_mu --> nu_e and bar{nu}_mu --> bar{nu}_e at neutrino energies ~ 2 GeV, as projected for the off-axis neutrino beam of NuMI.The neutral-current background to these reactions is less than to quasielastics, and can be further suppressed by reconstructing theprimary vertex of the collision.

hep-ex↗

arXiv2000

Detecting the (Quasi-)Two-Body Decays of $τ$ Leptons in Short-Baseline Neutrino Oscillation Experiments

Novel detector schemes are proposed for the short-baseline neutrino experiments of next generation, aimed at exploring the large-$Δm^2$ domain of \omutau oscillations in the appearance mode. These schemes emphasize good spectrometry for charged particles and for electromagnetic showers and efficient reconstruction of \ypi_gg decays. The basic elements are a sequence of relatively thin emulsion targets, immersed in magnetic field and interspersed with electronic trackers, and a fine-grained electromagnetic calorimeter built of lead glass. These elements act as an integral whole in reconstructing the electromagnetic showers. This conceptual scheme shows good performance in identifying the $τ$ (quasi-)two-body decays by their characteristic kinematics and in selecting the electronic decays of the $τ$.

hep-ex↗