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N ew detectors for meson spectroscopy in Hall B at JLab

N ew detectors for meson spectroscopy in Hall B at JLab. Baryons2013, June 27 2013. Gabriel Charles. New detectors for meson spectroscopy in hall-B at Jefferson Lab . 1) Meson spectroscopy at CLAS12 2) Feasibility 3) Detector development and time schedule.

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N ew detectors for meson spectroscopy in Hall B at JLab

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  1. New detectors for meson spectroscopy in Hall B at JLab Baryons2013, June 27 2013 Gabriel Charles

  2. New detectors for meson spectroscopy in hall-B at Jefferson Lab 1) Mesonspectroscopyat CLAS12 2) Feasibility 3) Detector development and time schedule Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 1

  3. Whymesonspectroscopy ? MesonspectroscopyatCLAS12 In the quark model, quantum numbers of mesons are constrained: Total angularmomentum J : |L-S|<J<L+S Parity P = Charge conjugation C = where L and S are respectively the orbital angularmomentum and the spin States for L=0,1,2 Forbidden states (, ...) are calledexoticmesons. Theycanbeglueballs, tetraquarks, a mesoncomposed of two quarks and one gluon ... The discovery of one these states wouldgive a strong proof of the existence of other quark-gluon configurations. The MesonEx collaboration has proposed to performmesonspectroscopyat CLAS12. Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 2

  4. Jefferson Lab, Newport News, Virginia MesonspectroscopyatCLAS12 • About the Hall B : • Started to take data in 1996 • Around 160 collaborators in 12 countries from more than 40 different institutions • Focused on understandingnucleon structure Hall C Hall A Hall B Main physics focus of the Hall B : What is the longitudinal and transverse structure of the hadron ? Whatis the 3D structure of the hadrons ? Whatis the hadronicspectra ? Hadrons and cold nuclear matter • About the accelerator : • Twolinearacceleratorsconnected by recirculation arcs • Continuouselectronbeam • Upgradedverysoon to deliver a 12 GeVelectronbeamat a luminosity of Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 3

  5. CLAS12 MesonspectroscopyatCLAS12 • Fixedtargetexperiment • 11 GeVcontinuouselectronbeam • liquidhydrogentarget • 4 detectors • good particule identification and energyresolution Spectropscopywill use quasi-real photons as a probe. As = 4EE’(θ/2), electronatlow angles must bedetected. new detectors atlow angles are required Example of studiedreactions Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 4

  6. Forward Tagger MesonspectroscopyatCLAS12 The Forward Tagger is 1.8 m awayfrom the target. It aims to reconstruct the scatteredelectronbetween 2.5° and 4.5°. Electromagneticcalorimeter Hodoscope Micromegastracker Three new detectors willbeadded to the Hall B : • Electromagneticcalorimeter to reconstruct the energy of the electron • Hodoscope to differenciate photons and electrons • Micromegastracker to determine the space variables of the electron The Forward Tagger has been implemented to Gemc and a full analysisperformed. Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 5

  7. Simulations Feasibility Full reconstruction of a 3reactionwith the software framework of CLAS12 has been performed. Missing mass reconstruction Acceptance Fast MC simulations Gemc X mass resolutionisaround 10 MeV/c². Good agreement betweenfastMonte Carlo and realistic simulations Excellent differenciation of 3 from 4 events + PWA to determine the quantum numbers Experimenthas been approvedwith 118 days of beam time. Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 6

  8. Calorimeter Detector developpment APD LED • The main elements of the calorimeter are : • a matrix of 332 crystals • eachcrstalis made of and has a rectangular shape of 15 x 15 x 200 • cooling system • APDs and pre-amplifiers amplifier crystal downstreampeek support Momentumresolutionfrom simulations Tooling for crystalassembly Resolutionis about 3.5 % from 2 to 4.5 GeV/c and 2 % at 0.5 GeV/c Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 7

  9. Hodoscope Detector developpment • The main elements of the hodoscope are : • twolayers of plastic scintillators (Eljen-204) to minimise photon mis-ID • The first layer is 7 mm thick and the second 15 mm thick • WLS fibers • silicon PM Time resolution (from simulations) Photon misidentification (from simulations) • Recent and on-goingwork : • design of the fiberholder • fiber protection • fiberconnector to the SiPM Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 8

  10. Micromegastracker Detector developpment • The main elements of the tracker are : • twolayers of twoMicromegas detectors • each detector has an internal radius of 67 mm and an external radius of 142 mm • a dedicatedelectronics for the 3,600 channels • signal cables of about 1 m Angularresolutions (from simulations) The detector isverysimilar to the Micromegasdevelopped by the CEA Saclay for the ForwardMicromegasTracker (FMT). Prototypes for the FMT have already been succefullytested and a prototype for the Forward Tagger willbetestedduring the summer. Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 9

  11. Mechanical design Detector developpment Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 10

  12. Time schedule Detector developpment Gabriel.Charles@cea.fr CEA Saclay Baryons2013, 06/27/2013 11

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