The hybrid mesons quest: the MesonEx experiment at Jefferson Laboratory

6th Young Researcher Meeting, L'Aquila 2015

Rizzo, A.^1

University of Rome Tor Vergata, INFN Roma2, Via della Ricerca Scientifica 1, Roma

00133, Italy^1

关键词: Analysis frameworks;    Constituent quark model;    Experimental apparatus;    Generation experiments;    National laboratory;    Partial wave analysis;    Scientific programs;    Statistical techniques;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/689/1/012022/pdf
DOI  :  10.1088/1742-6596/689/1/012022

来源: IOP

【 摘 要 】

The meson spectroscopy plays nowadays a central role in the investigation of hadron structure thanks to the possible existence of exotic hybrid mesons, quark-antiquark-gluon bound states. Their explicit gluonic degrees of freedom which should clearly emerge from a Partial Wave Analysis (PWA) of the corresponding Dalitz plot of the exotic particle decay, may result in final JPCconfigurations not allowed in the constituent quark model. Besides this clear signature, hybrid mesons are also expected to have a large particle multiplicity decays, requiring for their search an experimental apparatus with high performances in terms of rate capability, resolution and almost a full acceptance to apply PWA methods. New-generation experiments are planned at Thomas Jefferson National Laboratory (VA, USA) for which an unprecedented statistics of large multiplicity decay events with fully reconstructed kinematics will be available. In particular for the MesonEx (CLAS12) experiment in Hall B, a wide scientific program that will start in 2016 has been deployed to study the meson spectrum at energies up to 11 GeV. A key role in such program is played by the Forward Tagger apparatus of the experiment, which will allow to extend the study of meson electro-production to very low Q2values, in a quasi-real photo production kinematical region, where the production of hybrid mesons is expected to be favorite. Currently a new analysis framework for the search of the hybrid mesons is being set up by the HASPECT network, an international structure which gather people involved into theoretical and experimental hadronic physics all over the world. The goals of the network is to develop new analysis models and statistical techniques to unfold the signal and background distributions in high-statistics datasets. In this work are briefly presented the first preliminary results from the application of a statistical technique, namely the sPlot, to the data already acquired by the CLAS experiment for the decay f1(1285) → (η)π+π-.