Hyperon Polarization with ATLAS at the LHC

Introduction

We propose to compile, in these pages, up to date information on our investigation of Lambda-Hyperon (, ) Polarization studies at the LHC using the ATLAS detector. Earlier experiments at Fermilab (E799), DESY (HERA/HERMES) and BNL (/RHIC/STAR) have shown Lambda-hyperons which are by definition unpolarized, to acquire significant induced polarization. The mechanism through which this polarization is acquired is yet to be understood although many models exist.

FERMILAB: proton beam incident on Be target

HERA: polarized positron beam incident on unpolarized gas targets.

RHIC: proton-proton collisions with one of the protons longitudinally polarized.

LHC: unpolarized proton-proton beams.

Although our attempts to measure lambda polarization at ATLAS is not the first one conducted with unpolarized beams (NOMAD experiment at CERN) there is no doubt that it is the first time such attempt is made with the energy regime provided by the LHC.

Documents

Analysis and Results

Results presented here are the fruits of efforts conducted at 3 institutes: Yale University (O. Keith Baker, Moustapha Thioye, Dan Guest), University of Michigan ( Homer Neal, Daniel Scheirich, Junjie Zhu, Ray Zhang), and St-Petersburg Technical Institute (Oleg Grebenyuk)

Datasets

V0Finder hypothesis verification

Acceptance

Fakes

Links

-- MoustaphaThioye - 30-Apr-2010