Systematic Study of Spin Effects at SPASCHARM Experiment at 70-GeV Accelerator in Protvino

V V Mochalov,A P Meshchanin,N S Borisov,V L Rykov,Y A Usov,A A Derevschikov,S V Ryzhikov,S B Nurushev,N G Minaev,A N Vasiliev,A V Ryazantsev,D A Morozov,N A Bazhanov,V V Abramov,A S Evdokimova,M N Strikhanov,P A Semenov

doi:10.1142/s201019451660106x

Abstract

A new experiment SPASCHARM for systematic study of polarization phenomena in the inclusive and exclusive hadronic reactions in the energy range of IHEP accelerator U-70 (12–50[Formula: see text]GeV) is currently under development. The universal experimental setup will detect dozens of various resonances and stable particles produced in collisions of unpolarized beams with the polarized target, and at the next stage, using polarized proton and antiproton beams. At the beginning, the final states consisting of light quarks ([Formula: see text], [Formula: see text], [Formula: see text]) will be reconstructed, and later on the charmonium states will be studied. Measurements are planned for a variety of beams: [Formula: see text], antiprotons. Hyperon polarization and spin density matrix elements of the vector mesons will be measured along with the single-spin asymmetry (SSA). The 2[Formula: see text]-acceptance in azimuth, which is extremely useful for reduction of systematic errors in measurements of spin observables, will be implemented in the experiment. The solid angle acceptance of the setup, [Formula: see text] mrad vertically and 350 mrad horizontally in the beam fragmentation region, covers a wide range of kinematic variables [Formula: see text] and [Formula: see text]. This provides the opportunity for separating dependences on these two variables which is usually not possible in the setups with a small solid angle acceptance. Unlike some previous polarization experiments, the SPASCHARM will be able to simultaneously accumulate and record data on the both, charged and neutral particle production.

Highlights

The interest in studying spin dependences in strong interactions arises from the study of hadron’s spin structure through interactions of the constituent partons having non-zero spin
There has been a considerable progress achieved in the experimental study of spin effects at high energies
The main physics motivation of the SPASCHARM experiment is the systematic study of spin phenomena for a wide range of inclusive and exclusive reactions in collisions of high-energy polarized hadrons in the QCD non-perturbative region

Summary

Introduction

The interest in studying spin dependences in strong interactions arises from the study of hadron’s spin structure through interactions of the constituent partons having non-zero spin. There has been a considerable progress achieved in the experimental study of spin effects at high energies. The new experimental program, the SPASCHARM for 70-GeV proton synchrotron (U-70), is currently under development at the Institute for High Energy Physics (IHEP), Protvino, Russia. The main physics motivation of the SPASCHARM experiment is the systematic study of spin phenomena for a wide range of inclusive and exclusive reactions in collisions of high-energy polarized hadrons in the QCD non-perturbative region. This opens the possibility to detect charged and neutral particles in the final state in a large solid angle in the energy range of 12–50 GeV. Along with a number of various beams available in the channel, including polarized proton and antiproton beams at the second stage of the experiment, the large acceptance would allow us to explore dozens of different reactions

Physics Motivation

The Main Objectives of the Experiment

Findings

Summary