arXiv subjects

N. Savvinov

Publications and source records attributed to N. Savvinov.

10 recordsLinked to original sources

arXiv2010

Probing Quark-Gluon Interactions with Transverse Polarized Scattering

We have extracted QCD matrix elements from our data on double polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element \tilde{d_2}, which arises strictly from quark- gluon interactions, to be unambiguously non zero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham Sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer.

nucl-ex↗

arXiv2007

Large underground, liquid based detectors for astro-particle physics in Europe: scientific case and prospects

This document reports on a series of experimental and theoretical studies conducted to assess the astro-particle physics potential of three future large-scale particle detectors proposed in Europe as next generation underground observatories. The proposed apparatus employ three different and, to some extent, complementary detection techniques: GLACIER (liquid Argon TPC), LENA (liquid scintillator) and MEMPHYS (\WC), based on the use of large mass of liquids as active detection media. The results of these studies are presented along with a critical discussion of the performance attainable by the three proposed approaches coupled to existing or planned underground laboratories, in relation to open and outstanding physics issues such as the search for matter instability, the detection of astrophysical- and geo-neutrinos and to the possible use of these detectors in future high-intensity neutrino beams.

hep-ph↗

arXiv2007

Track reconstruction in the emulsion-lead target of the OPERA experiment using the ESS microscope

The OPERA experiment, designed to conclusively prove the existence of $\rm ν_μ\to ν_τ$ oscillations in the atmospheric sector, makes use of a massive lead-nuclear emulsion target to observe the appearance of $\rm ν_τ$'s in the CNGS $\rm ν_μ$ beam. The location and analysis of the neutrino interactions in quasi real-time required the development of fast computer-controlled microscopes able to reconstruct particle tracks with sub-micron precision and high efficiency at a speed of 20 cm^2 / h. This paper describes the performance in particle track reconstruction of the European Scanning System, a novel automatic microscope for the measurement of emulsion films developed for OPERA.

physics.ins-det↗

arXiv2007

Proton Spin Structure in the Resonance Region

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q^2 = 1.3 GeV^2. Using the Jefferson Lab polarized electron beam, a spectrometer, and a polarized solid target, we measured the asymmetries A_parallel and A_perp to high precision, and extracted the asymmetries A_1 and A_2, and the spin structure functions g_1 and g_2. We found a notably non-zero A_perp, significant contributions from higher-twist effects, and only weak support for polarized quark--hadron duality.

nucl-ex↗

arXiv2007

Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network

We have studied the performance of a new algorithm for electron/pion separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion films. The software for separation consists of two parts: a shower reconstruction algorithm and a Neural Network that assigns to each reconstructed shower the probability to be an electron or a pion. The performance has been studied for the ECC of the OPERA experiment [1]. The $e/π$ separation algorithm has been optimized by using a detailed Monte Carlo simulation of the ECC and tested on real data taken at CERN (pion beams) and at DESY (electron beams). The algorithm allows to achieve a 90% electron identification efficiency with a pion misidentification smaller than 1% for energies higher than 2 GeV.

physics.data-an↗

arXiv2006

Hardware performance of a scanning system for high speed analysis of nuclear emulsions

The use of nuclear emulsions in very large physics experiments is now possible thanks to the recent improvements in the industrial production of emulsions and to the development of fast automated microscopes. In this paper the hardware performances of the European Scanning System (ESS) are described. The ESS is a very fast automatic system developed for the mass scanning of the emulsions of the OPERA experiment, which requires microscopes with scanning speeds of about 20 cm^2/h in an emulsion volume of 44 micron thickness.

physics.ins-det↗

arXiv2006

A novel automatic film changer for high-speed analysis of nuclear emulsions

This paper describes the recent development of a novel automatic computer-controlled manipulator for emulsion film placement and removal at the microscope object table (also called stage). The manipulator is designed for mass scanning of emulsion films for the OPERA neutrino oscillation experiment and provides emulsion changing time shorter than 30 seconds with an emulsion film positioning accuracy as good as 20 microns RMS.

physics.ins-det↗

arXiv2006

Searching for neutrino oscillations with OPERA

The OPERA experiment will search for neutrino oscillations using a muon neutrino beam and a hybrid emulsion-scintillator detector. Basic principles, current status and expected performance of the experiment are discussed.

hep-ex↗

arXiv2004

Measurement of the Electric Form Factor of the Neutron at Q^2=0.5 and 1.0 (GeV/c)^2

The electric form factor of the neutron was determined from measurements of the \vec{d}(\vec{e},e' n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find G_E^n = 0.0526 +/- 0.0033 (stat) +/- 0.0026 (sys) and 0.0454 +/- 0.0054 +/- 0.0037 at Q^2 = 0.5 and 1.0 (GeV/c)^2, respectively.

nucl-ex↗

arXiv2002

Measurement of the Charge Form Factor of the Neutron $G^{E}_{n}$ from ${\vec{d}(\vec{e},e'n)p}$ at $Q^{2}=0.5$ and $1.0 (GeV/c)^{2}$

We determined the electric form factor of the neutron $G_E^n$ via the reaction ${\vec{d}(\vec{e},e'n)p}$ using a longitudinally polarized electron beam and a frozen, polarized $^{15}ND_3$ target at Jefferson Lab. The knocked out neutrons were detected in a segmented plastic scintillator in coincidence with the quasi-elastically scattered electrons which were tracked in Hall C's High Momentum Spectrometer. To extract $G_E^n$, we compared the experimental beam--target asymmetry with theoretical calculations based on different $G_E^n$ models. We report the preliminary results of the fall 2001 run at $Q^{2}=0.5$ and $1.0 (GeV/c)^{2}$.

nucl-ex↗