The Jefferson Laboratory and the Italian collaboration Physics (excerpt)
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Transcript of The Jefferson Laboratory and the Italian collaboration Physics (excerpt)
IFAE 2012 / Ferrara E. Cisbani / Experimental Physics at JLab 1
27 Settembre 2013XCIX Congresso SIF 2013 – Trieste
G.M. Urciuoli, M. Battaglieri
L’esperimento JLAB12 The Jefferson Laboratory and the Italian collaboration Physics (excerpt)
• Nucleon Structure (Form Factor and Quark Distribution)• Parity Violation Experiments• Hypernuclei• Nuclear Structure
Technological Developments• HD Polarized Target• Photon Tagger• RICH/Clas12• GEM/SiD Trackers
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Thomas Jefferson National Laboratory
• Newport News / Virginia / USA (3 ore da Washington DC)
• DOE funding + Local Universities and Organizations
• Director: H. E. Montgomery (ex-associate director for research al Fermilab)
• 2000 International Users• Fundamental Research by electron
accelerator on 3+1 experimental Halls• Applied research by FEL and other facilities• Web site: www.jlab.org
more than
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CEBAF accelerator
A B C
Lina
c
Linac
Arc
Arc
Injector
• Linear Recirculating e- Accelerator with
superconductive cavities• Polarized beam
• High current (200 mA)• Max. energy 6 GeV
• 100% duty factor• Beam released
simultaneously on three experimental Halls: A, B
and C
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Hall A Hall B/CLAS Hall CTwo High Momentum
Resolution + one large angular acceptance spectrometers
Dedicated neutron and gamma detectors
Large acceptanceHigh multiplicity
reconstructionSix coils Toroidal
field
Two asymmetric spectrometers
High momentum range and high resolution
Dedicated detectors
High beam currents (>100 mA), lumi 1037
cm-2 s-1
Tagged real photons beam
High beam currents (>100 mA), lumi 1037
cm-2 s-1
3He T/L Polarized target, high flexibility unpol. from H to Pb
NH3/ND3 Polarized long. target
NH3/ND3 Polarized long. target, high flexibility unpol. from H to Pb
Large and flexible installations
4p coverage Moderately large and flexible installations
Current Experimental Halls
5
CEBAF after 2013
CHL-2
Upgrade magnets and power supplies
add Hall D (and beam line)6 GeV CEBAF (< 2013)
Max Current: 200 mAMax Energy: 0.8 - 5.7 GeVLong. Polarization: 75-85%
12 GeV CEBAF
(>2013)Max Current: 90 mAMax Energy Hall A,B,C: 10.9 GeVMax Energy Hall D: 12 GeVLong. Polarization: 75-85%
$ 310M
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Hall A Hall B/CLAS12 Hall C Hall D/GLUEX+ 1 large angular and
momentum, high lumi spectrometer with hadron ID
+ Solid detector+ Möller detectorNew beam line
New ~2p toroid detector with extended hadron ID
+ “super high” momentum spectrometer
+ dedicated equipment
Excellent hermetic coverage,
Solenoid fieldHigh multiplicity
reconstruction
+ lumi 1038 cm-2 s-1 + forward tagger for quasi-real photons
108 linearly polarized <12 GeV
real photons/s
+ targets with large thickness
+ long/trans polarized H/D target
hallaweb.jlab.org www.jlab.org/Hall-B www.jlab.org/Hall-Cwww.jlab.org/Hall-D
www.gluex.org
Experimental Halls after 2014
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JLab physics• Origin of quark and gluon confinement (B & D)– Gluonic excitations - existence and properties of exotic mesons (and baryons)– Heavy baryon and meson spectroscopy
• Structure of the Hadrons (A,B and C)– Parton Distributions Functions (and Fragmentation Functions)– New view of nucleon structure via the Generalized Parton Distributions (GPDs)
accessed in Exclusive Reactions– Form Factors - improve knowledge of charge and current in the nucleons;
constraints on the GPDs– Quark propagation and hadron formation
• Dynamics of the nucleons in the nuclei (A, B and C)– The Quark Structure of Nuclei (resolving the EMC effect)– The Short-Range Behavior of the N-N Interaction and its QCD Basis– Cold nuclear matter
• Electroweak Interaction (A and C)– High Precision Tests of the Standard Model at low energies via Parity-Violating
Electron Scattering Experiments– Measure nuclear properties by weak interaction
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Sezioni INFN partecipanti (BA, CA, CT, GE, FE, ISS, LNF, PD, RM, RM2, TO):Ricercatori + Tecnologi: ~ 60 (41.2 FTE)
Intensa attività sperimentale al JLab/6 GeV (prevalentemente in sala A e B) Forte coinvolgimento negli sviluppi legati al raddoppio di energia del fascio e aggiornamento degli apparati nelle sale sperimentali
Esperimento INFN formalmente attivo
dal 2009 per 7 anni, nasce dalla
sinergia delle ex sigle AIACE + LEDA
per sfruttare al meglio le opportunità
sperimentali offerte
dall’aggiornamento a 12 GeV
TMD’s latest results at JLab
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First ‘direct’ measurement on neutron
n - Collins small, largely compatible to 0; Sivers negative (?) for p+, zero for p-
Collins Moment = h1 Collins FF Clean probe of relativistic effects
Sivers Asymmetry = f1T TMD Unpol. FF
Link to quark Orbital Angular Momentum
Experimental limits:Modest statistics, integrated on the relevant kinematical variables (x,z,pT),no access to large x, valence region, no clean interpretation of the data.
Adapted from A. Puckett, JLab 2011
D
F TMDs @ JLab 12 GeV
E12-09-018: p/kE12-10-006: p
3He
Hall A SBS/SOLID
HALL CHMS+SHMS
E12-09-017: p/kC12-11-102 p0
Hall BCLAS12
C12-11-111: p/k
H2, D2NH3HDH2, NH3, D2,
ND3
E12-06-112: pE12-09-008: k
E12-07-107: pE12-09-009: k
A Multi-Hall TMDs program - Large variety of targets- Different species of detected hadrons
-High luminosity experiments- Extended phase space
Adapted from P. Rossi, JLab 2012
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E12-11-107: p
C12-11-108: p
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Proton Form Factors
2tan
2)( e
p
ebeam
l
t
Mp
Ep
MEE
PP
GG mm
Polarization transfer from the incident electron to the scattered proton
22MpEp GG
dd
Rosenbluth Separation: assume single photon approximation
Prior to JLab, expectations were that Gep/GMp was fairly constant with Q2
New focus on nucleon structure and description of elastis scattering (two photon exchange); possible role of quark OAM
e + p → e’ + p’
e→ + p → e’ + p →’
At JLab, new class of experiments show GE/GMp decreasing linearly with Q2
Extended measurements of p/n form factors at high Q2
Test different models (including different contributions from the quark OAM)
Investigate the transition region (perturbative / non perturbative)
Constraint the H and E GPDs
Electromagnetic Nucleon Form Factors @12GeVE-12-07-109: Polarization transfer E-12-09-016: Double polarization
E-12-09-019: Cross section ratio
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0Z
e e
+
2
Esperimenti di Violazione della Parità• Misura accurata della asimmetria nei processi elastici (e DIS) di elettroni
polarizzati longitudinalmente su nucleone/nucleo non polarizzato
• Accesso alle costanti di accoppiamento deboli elettroni-quark (u/d) delle correnti neutre, ovvero alla corrente debole del protone, ovvero all’angolo di mixing debole
• Pone limiti su esistenza di nuova fisica (PVDIS, QWeak, Möller) • Ha permesso la misura del contributo dei quark s ai fattori di forma del
nucleone (HAPPEX, G0)• Permette la misura di importanti grandezze nucleari soppressi nei
processi elettromagnetici PREX
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A neutron skin established at ~93 % CL
Neutron Skin = RN - RP = 0.33 + 0.16 - 0.18 fm
Neutron Radius = RN = 5.78 + 0.15 - 0.17 fm
Pins down the symmetry energy (1 parameter)
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First direct measurement of the neutron skin
PREX-II Approved by PAC (Aug 2011)
Lead (208Pb) Radius Experiment: PREXE = 850 MeV, =6° electrons on lead
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Future equipment for PaVi experiments at Jlab/Hall A
SOLID (PV e- - q scattering + SIDIS) - PV e-quark - High precision TMD Parity Violation Physics to test the SM at low energy: require high luminosity and
precise control of the systematics
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Publ
ished
Study Λ-N Interaction potential
Hypernuclei at JLab
Experimental requirements:- Excellent Energy Resolution- Detection at very forward angles (6°→septum magnets)
- Excellent PId for kaon selection →RICH- High luminosity
Reactions Investigated: 9Be→9LiΛ (3 spin doublets, information on Δ)
12C→12BΛ (evidence of excited core states → sN contribution)
16O→16NΛ (unmatched peak may indicate large sΛ term)
H →Λ,Σ0 (elementary process)
Experiment E94-107Hypernuclear spectroscopy9Be (e,e’k+) 9
ΛLi reaction
Thanks to energy resolution improvements a clear three peak structure appears in the excitation energy spectrum. RM1, ISS
Analisi dell’esperimento sulla produzione di ipernuclei a Jlab completamente in mano alla collaborazione italiana:- M. Iodice, F. Cusanno et al., Phys. Rev. Lett. 99, 052501 (2007) (ipernucleo 12
ΛB) - F. Cusanno, G.M. Urciuoli et al., Phys Rev. Lett. 103 202501 (2009) (ipernucleo 16
ΛN) - G.M. Urciuoli, F. Cusanno, S. Marrone et al. Sottomesso a PHYS REV C
Experiment E06-007208Pb(e,e’p)207Tl and 209Bi(e,e’p)207Pb cross sections at true
quasielastic kinematics (xB=1, q=1 GeV/c, ω=0.433 GeV/c ) and at both sides of q Never been done before for A>16 nucleus
RM1, ISS
★ Determine the spectroscopic factors dependence with Q2
★ Long range correlations: not needed!★ Relativistic effect in nuclei: needed!
Search for dark force: HPS in Hall-B
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- - - - - - - - - - - - 1 week 1.1 GeV
- - - - - - - - - - - - 1 week 2.2 GeV
3 months 2.2 GeV
3 months 6.6 GeV
Bump hunting
Bump hunting+ vertexing
Phase 1expected 2014/15
Phase 22015 or later
HPS Projected results
JLab1212 GeV era / Equipment
• HD Target,
• Forward Tagger,
• RICH,
• High Lumi Tracker
HD-ice: polarized frozen spin HD targetPolarized target of high dilution factor, made of solid Deuterium-Hydride:Longitudinal and Transverse Polarizations: up to 75% H and 40% DRelaxation time: > 1 year Polarization procedure » 3 monthsData taking: » monthsWide acceptance
Target cell
Comparison of signal over background ratio:HD versus conventional polarized target
INFN contribution:• Dilution Refrigerator• Contribution to the construction of the new In-
Beam Dilution Refrigerator Cryostat• Raman analysis of ortho-hydrogen and para-
deuterium contents in HD gas• Magnetic Vari-Temp Cryostat for HD
condensation and NMR polarization measurements
Target Transfer
In-beam cryostat
Run with polarized deuterons from HD-ice & circularly polarized photons started on Dec. 2011: D polarization 27%
Run with polarized deuterons from HD-ice & linearly polarized photons started on April 2012: D polarization 30%
Test of HD-ice & electron beam performed in February: on-going analysis
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The Forward Tagger for CLAS12
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New system to detect electrons at small angle and perform quasi-real photo-production experiments
Calorimeterelectron energy/momentumPhoton energy (ν=E-E')Polarization ε-1 ≈1 + ν2/2EE’PbWO4 crystals with APD/SiPM readout
Scintillation Hodoscopeveto for photonsScintillator tiles with WLS readout,…
Trackerelectron anglesPolarization scattering planeMicroMegas detectors
Moller Shield
CalorimeterTracker
Scintillation Hodoscope
HTCC Moller cup
GEMC implementation
e-*
CLAS12
p
e-
ForwardTagger
Adapted from M. Battaglieri, Genova 2012 22
AerogelElliptical mirrors
Photo-detectors
+ Planarmirrors
Proximity Focusing RICH + MirrorsRICH Conceptual Design
Goal: reduce the photon detection area of MA-PMTs H8500 to ~ 1m2/sector
Elliptical and planar mirrors to focus the Cherenkov light of particles emitted at angles > 12°
10 H8500
8 R8900
- Test with hadron beam at CERN with a prelininary RICH prototype (summer 2011)
number of Np.e obtained for direct ring in consistent with simulations- Test with electron beam at LNF (july 2012)- test of full prototype with p/K beam at CERN (august 2012) 23
UvaJLabINFNRutgers U.College WMU. of GlasgowNorfolk State U.Carnegie Mellon U.U. of New Hampshire
SBS Spectrometer in Hall A
SiD
High luminosity ~1039/s/cm2 Moderate acceptanceForward angles Reconfigurable detectors
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40x150 cm2 GEM Tracker70 mm spatial resolution
High photons up to 250 MHz/cm2 and electrons 160 kHz/cm2 background
Spare
RICH detector for CLAS12DC R3R2R1
EC
Torus
TOF
PCAL
HTCC
Solenoid
LTCC
INSTITUTIONS
ARGONNE NL
INFNBari, Ferrara, Genova, Frascati, Roma/ISSGLASGOW U.JLABU. CONNUTFSM (Chile)
GeV/c
1 2 3 4 5 6 7 8 9 10
p/K
p/p
K/p
TOFHTCC
LTCC
TOF
TOF
LTCCHTCC
full pion / kaon / proton separation in 2–8 GeV/c range
p/K separation of 4-5 @ 8 GeV/c for a rejection factor ~1000
x RICH
Aerogel mandatory to separate hadrons in the 2-8 GeV/c momentum range collection of visible Cherenkov light use of MA-PMTs
Option under investigation:proximity focusing RICH + mirrors (innovative geometry)
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CLAS12 PID
RICH
GeV/c 1 2 3 4 5 6 7 8 9 10
p/K
p/p
K/pe/p
HTCC
TOF
TOF
TOF
HTCC
HTCC
HTCCEC/PCAL
LTCC
RICHRICH
LTCCRICHLTCCLTCCRICHLTCCRICH
4-5 p/K separation @ 8 GeV/c
Aerogel mandatory to separate hadrons in the 2-8 GeV/c momentum range collection of visible Cherenkov light use of PMTs
Challenging project, crucial to minimize Detector area
Option under investigation: proximity focusing RICH + mirrors
IFA
E 20
12 /
Ferr
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E. C
isba
ni /
Expe
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tal P
hysi
cs a
t JLa
b27Adapted from P. Rossi, JLab 2012
New RICH geometry
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Aerogel
Flat Mirror + Aerogel Active Photon Detector
Adapted from L. Pappalardo Roma 2011
RICH preliminary prototype
10 H8500
8 R8900
Aerogel
MA-PMTs
Electronics
Maroc2 front end electronics developed for nuclear medicine• preamplifier, adjustable from 1/8 to 4• ADC, about 80fC per channel
Hit distributions
Ebeam
(GeV)Aerogel <d>
(cm)<R(p)>
cmt (cm) n
10 1 1.05 35.1 11.210 2 1.05 34.6 11.110 3 1.05 34.1 10.910 3 1.03 48.8 12.04 1 1.03 49.8 12.2
N.B. 1 and 2 cm means 2 or 3 blocks of 1 cm
1cm 2cm 3cm
aerogel n=1.03
aerogel n=1.05
integrated distributions of hits above
threshold3cm
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Meson Spectroscopy in CLAS12The study of the light-quark meson spectrum and the search for exotic quark-gluon configurations is crucial to reach a deep understanding of QCD:• identify relevant degrees of freedom• understand the role of gluons and the origin of
confinementPhoto-production is the ideal tool:• linearly polarized photon beam (NEW!)• large acceptance detector (CLAS12)
Forward TaggerE’ 0.5-4.5 GeVn 7-10.5 GeVq 2.5-4.55 degQ2 0.007 – 0.3 GeV2
W 3.6-4.5 GeVPhoton Flux 5 x 107 /s @ Le=1035
Quasi-real photoproduction with CLAS12(Low Q2 electron scattering)
e-γ*
CLAS12
p
e-
ForwardTagger
Tracker Electron angle
Hodoscope Photon veto
Calorimeter Electron Momentum/EnergyAdapted from R. De Vita, Roma/2011
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Choice of the technology
System RequirementsTracking Technology
Drift MPGD Silicon
High Background Rate (up to):(low energy and e) 1 MHz/cm2
NO MHz/mm2 MHz/mm2
High Resolution (down to):70 mm
Achievable 50 mm 30 mm
Large Area:from 40×150 to 80×300 cm2
YES Doable Very Expensive
… and modular: reuse in different geometrical configurations Flexibility in readout geometry
and lower spark rate
GEM mMs
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GEM working principle
Ionization
Multiplication
Readout
Multiplication
Multiplication
Readout independent from ionization and multiplication stages
Recent technology: F. Sauli, Nucl. Instrum. Methods A386(1997)531
GEM foil: 50 mm Kapton + few mm copper on both sides with 70 mm holes, 140 mm pitch
Strong electrostatic field in the GEM holes
SBS Tracker GEM Chambers configuration
Modules are composed to form larger chambers with different sizes
Electronics along the borders and behind the frame (at 90°) – cyan and blue in drawing
Carbon fiber support frame around the chamber (cyan in drawing); dedicated to each chamber configuration
Front TrackerGeometry
x6
Back Trackers Geometry
X(4+4)
GEp(5) SBS
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MonteCarlo + Digitazation + Tracking
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High + e background hits~ MHz/cm2
(Signal is red)
Bogdan Wojtsekhowski + Ole Hansen+ Vahe Mamyan et al.
6 GEM chambers with x/y readoutUse multisamples (signal shape)
for background filtering
Assembling the first 40x50 cm2 module
Stretching
Gluing the nextframe with spacers
Foil Tension: T = 2 kg/cmSpacer Sector: S = 170 cm2Expected maximum pressure on foil P 10 N/m2
Maximum foil deformation:u 0.0074 * P * S / T = 6.4 mm
Use stretching and spacersto keep foil flat
Stretcher design from LNF / Bencivenni et al.
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Beam test @ DESY / Full Module Size 40x50 cm2
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Electronics Readout (GEM and SiD)
GEM FEC MPD DAQ
2D R
eado
ut
75 mm
49.5
mm
8 mm
Up to 10mtwisted,shielded
copper cable(HDMI)
Passive backplane(optional)
Main features:• Use analog readout APV25 chips (analog and time information)• 2 “active” components: Front-End card and VME64x custom module • Copper cables between front-end and VME• Optional backplane (user designed) acting as signal bus, electrical
shielding, GND distributor and mechanical support
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+ Small Silicon Detector
Track
Angular Range
Chamber doubletDipole
SD(x/y)
21 Set 2009 / CSN III JLab12 - E. Cisbani 39
5mm
5mm
10mm
10mm
8.5mm8.5mm6.5mm
A
A
B
B
C
C
D
D103500
Disegno custom per JLAB12da un wafer di 6” (152mm)
40
30 cm
23 cm
41
fori di fissaggio
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Fan Out PCB
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Equipment / Physics Matrix @ 12 GeV
EquipmentPhysics
HDTarget RICH Forward
TaggerGEM
TrackerSi
Detector
TMDs, nucleon
spin structure
X X X X
Meson Study X
Form Factors X X
Parity Violating Electron
ScatteringX
Intensa attività di sviluppo tecnologico per un esteso programma di fisica
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The “ultimate” description of the nucleon
3D view of the nucleon
Transverse Momentum Dependent (TMD) parton distribution and fragmentation functions • Describe correlations between the transverse
momentum of quarks/gluons and spin• 3D picture of nucleon in momentum space
Generalized Parton Distribution functions (GPD) • Describe correlations between the transverse
coordinates of quarks and spin• 3D picture of nucleon in mixed momentum and
transverse spaceN
ucle
on
Quark
Information on: nucleon spin origin, quark orbital angular momentum,relativistic effects in QCD, quark/gluon Q2 evolution,
QCD gauge invariances ...
44Adapted from P. Rossi, JLab 2012
Some TMDs projections
SOLID: e3He →e’p+/-X
E12-11-007
E12-09-009
CLAS12: e p →e’K+/-X longitudinally polarized target
6 GeV data
SBS: e3He →e’K+/- X(transverse target)
E12-09-018 45Adapted from P. Rossi. JLab 2012
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Different (e,e’h) experimental configurationsExperiments Luminosity
(s·cm2)-1
Tracking Area(cm2)
ResolutionAngular(mrad)
Vertex(mm)
Momentum(%)
GMn - GEn up to 7·1037 40x150 and 50x200
< 1 <2 0.5%
GEp(5) up to 8·1038
40x120, 50x200 and
80x300
<0.7~1.5
~ 1 0.5%
SIDIS up to 2·1037 40x120,40x150 and
50x200
~ 0.5 ~1 <1%
Maximum reusability: same trackers in different setups
Most demanding
HighRates
LargeArea
Down to ~ 70 mmspatial resolution
47
Confinement Mechanism
(hadronization and spectroscopy)
Hadronization of quarks
48
H. Matevosyan et al., Phys. Rev. D85 (2012) 014021
Transverse momentum distributions in hadronization may be flavor dependent
Employ nuclei as analyzers of hadronization processes, to probe:- The hadronization formation length
(0-10 fm)
- The time scale on which a qq pair becomes dressed with its own gluonic field
Study the SIDIS reaction on nuclei;
observables:
- The hadronic multiplicity ratio
- The transverse momentum broadening
Adapted from P. Rossi, JLab 2012 E12-06-117
How hadrons form inscattering processes ?
Beyond the quark model: hybrids and exotics
mesons
Quarks are confined inside colorless hadronsthey combine to 'neutralize' color force
baryons
Other quark-gluon configuration can give colorless objects
QCD does not prohibit such states but not yet unambiguously observed
q qq
molecules glueball mesons hybrid mesonspentaquarks
qqq
q
q
q
q q
qqq
Adapted from M. Battaglieri, Genova 2012 49
Hybrid mesons and glueballs mass range
1.4 – 3.0 GeV
Lattice-QCD predictions for the lowest exotics states:
0+- 1.9 GeV1-+ 1.6 GeV
This mass range is accessible in photoproduction experiments with a beam energy in the range 5 GeV < E <12 GeVPerfectly matched to JLab12 energy!
QCD Lattice calculations
Exotics
ρ
Standard mesons
J.Dudek et al Phys.Rev.D82 (2010) 034508
Adapted from M. Battaglieri, Genova 2012 50
Unambiguous experimental signature for the presence of gluonic degrees of freedom in the spectrum of mesonic states
S=S1+S2 J= L+S P = (-1) L+1 C= (-1) L+S
Combine excited glue quantum number with those of the quarks
Normal meson:flux tube in ground statem=0CP=(-1) S+1
Hybrid meson:flux tube in excited statem=1CP=(-1) S
Flux tube JPC 1-+ , 1+-
Search for mesons with 'exotic' quantum numbers(not compatible with quark-model)
Not-allowed: JPC = 0-- , 0+- , 1-+ , 2+- ...
Meson spectroscopy with photons at JLab
Adapted from M. Battaglieri, Genova 2012 51
Hall-D - GlueX Detector Hall-B - CLAS12 Detector
Meson spectroscopy with photons at JLab-12 GeV
• Good resolution• Good pID• Reasonable hermeticity• Un-uniform acceptance
• Good hermeticity• Uniform acceptance• Limited resolution• Limited pID
Forward Tagger
• Determination of JPC of meson states requires PWA• Decay and production of exclusive reactions• Good acceptance, energy resolution, particle identification
52Adapted from M. Battaglieri, Genova 2012