THE EXPERIMENT Curtis A. Meyer Carnegie Mellon 2 June - - PowerPoint PPT Presentation

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THE EXPERIMENT Curtis A. Meyer Carnegie Mellon 2 June - - PowerPoint PPT Presentation

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THE EXPERIMENT Curtis A. Meyer Carnegie Mellon 2 June 4, 2016 Meson 2016 - C.A. Meyer The GlueX Collaboration Arizona State, Athens, Carnegie Mellon, Catholic University, Univ. of Connecticut, Florida International, Florida State,

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SLIDE 1

THE EXPERIMENT

Curtis A. Meyer Carnegie Mellon

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SLIDE 2

The GlueX Collaboration

Arizona State, Athens, Carnegie Mellon, Catholic University,

  • Univ. of Connecticut, Florida International, Florida State,

George Washington, Glasgow, GSI, Indiana University, ITEP, Jefferson Lab, U. Mass Amherst, MIT, MePhi, Norfolk State, North Carolina A&T, Univ. North Carolina Wilmington, Northwestern, Santa Maria, University of Regina, Tomsk and Yerevan Physics Institute. Over 120 collaborators from 24 institutions with others joining and more are welcome.

June 4, 2016 Meson 2016 - C.A. Meyer

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SLIDE 3

Outline

  • The GlueX physics program.
  • The GlueX experiment and its performance

during commissioning.

  • Expected initial physics from GlueX.
  • Future plans and other physics.
  • Summary.

June 4, 2016 Meson 2016 - C.A. Meyer

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12-GeV beam, Dec.2015

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SLIDE 4

Quantum Chromo Dynamics

June 4, 2016 Meson 2016 - C.A. Meyer

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QCD describes the interactions of quarks and gluons and should predict the spectrum of bound- state baryons ( ) and mesons ( ). There should also be mesons in which the gluonic field contributes directly to the JPC quantum numbers of the states --- hybrid

  • mesons. Some are expected to have ``exotic’’

quantum numbers. qq qqq

Lattice QCD calculation of the light-quark meson spectrum.

``Constituent gluon’’: JPC = 1+- mass of 1-1.5 GeV. The lightest hybrid nonets 1--, (0-+,1-+, 2-+)

exotics

u ¯ d s¯ s u¯ u

2.0GeV

0+- 2+- 1-+

2.5Gev

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SLIDE 5

Lattice QCD

June 4, 2016 Meson 2016 - C.A. Meyer

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0.5 1.0 1.5 2.0 2.5

exotics isoscalar isovector YM glueball negative parity positive parity

Light-quark Mesons (u,d,s) 1 √ 2

  • uu − dd
  • 1

√ 2

  • uu + dd
  • (ss)

PRD83, 111502 & PRD88, 094505

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SLIDE 6

Lattice QCD

June 4, 2016 Meson 2016 - C.A. Meyer

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0.5 1.0 1.5 2.0 2.5

exotics isoscalar isovector YM glueball negative parity positive parity

Light-quark Mesons (u,d,s) 1 √ 2

  • uu − dd
  • 1

√ 2

  • uu + dd
  • (ss)

States with non-trivial gluonic fields.

Fj,µν F µν

j

1-- 0-+ 2-+ 1-+ 1--, 0-+ , 1-+ , 2-+ Supermultiplet

PRD83, 111502 & PRD88, 094505

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SLIDE 7

June 4, 2016 Meson 2016 - C.A. Meyer

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QCD Exotics

π1 IG(JPC)=1-(1-+) η’

1 IG(JPC)=0+(1-+)

η1 IG(JPC)=0+(1-+) K1 IG(JPC)= ½ (1-)

La#ce QCD suggests 5 nonets of mesons with exo7c quantum number: 1 nonet of 0+- exo7c mesons 2 nonets of 1-+ exo7c mesons 2 nonets of 2+- exo7c mesons π1 η1 Experimental evidence exists for π1 states.

``Constituent gluon’’ behaves like JPC = 1+- with a mass of 1-1.5 GeV The lightest hybrid nonets: 1--, (0-+,1-+, 2-+)

exotics

u ¯ d s¯ s u¯ u

2.0GeV

0+- 2+- 1-+

2.5Gev Kaon states do not have exotic QNs

PRD84, 074023

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SLIDE 8

Photoproduction Mechanisms

June 4, 2016 Meson 2016 - C.A. Meyer

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ρ,ω,φ γ p N X π,η,ρ,ω,P,...

Simple quantum number counting for production: (IG)JPC up to L=2 ρπ,ρω π1 ωω,ρρ η1 ωω,ρρ,φω η’1 ρP b0 ωP h0 ωP, φP h’0 ωπ,ρη,ρP b2 ρπ,ωη,ωP h2 ρπ,ωη,φP h’2

ρπ is charge-exchange only Can couple to all the lightest exotic hybrid nonets through photo- production and VMD. Linear polarization is a filter on the naturality of the exchanged particle.

P = Pomeron exchange

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SLIDE 9

June 4, 2016 Meson 2016 - C.A. Meyer

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Hybrid kaons do not have exotic QN’s

Decay Modes of Exotic Hybrids

π1 → πρ πρ, πb1 , πf1,πη’, ηa1 η1 → ηf2,a2π,ηf1, ηη ηη’,π(1300)π, a1π, η1’→ K*Κ, Κ1(1270)Κ, Κ1(1410)Κ , ηη ηη’ b2 → ωπ ωπ, a2π, ρη ρη, f1ρ, a1π, h1π, b1η h2 → ρπ ρπ,b1π,ωη, f1ω h’2 → Κ1(1270)Κ, Κ1(1410)Κ, K2

*Κ, φη, f1φ

b0 → π(1300)π , h1π, f1ρ, b1η h0 → b1π , h1η h’0 → K1(1270)Κ, Κ(1460)Κ, h1η

Early Reach With Statistics Hard

Models suggest narrower states are in the spin-1 and spin-2 nonets, while the spin-0 nonets are broad.

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SLIDE 10

The GlueX Experiment

June 4, 2016 Meson 2016 - C.A. Meyer

10 barrel calorimeter time-of

  • flight

forward calorimeter photon beam electron beam electron beam superconducting magnet target tagger magnet tagger to detector distance is not to scale diamond wafer

GlueX

central drift chamber forward drift chambers

Photo Production of Hybrids, Light-quark Mesons and Strangeonium States Initial Physics in 2016

BaBar DIRC Bars

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SLIDE 11

The GlueX Experiment

June 4, 2016 Meson 2016 - C.A. Meyer

11 75 m Collimator

select < 25 r polarized photons

Hall-D

Diamond Radiator

​"↑− "%→&​"↑− % Tagger Area

Photon Tagger Pair Spectrometer GlueX Spectrometer Photon Beam Dump Electron Beam Dump East ARC North LINAC

  • 12 GeV e- beam up to 2.2 µA.
  • Linearly polarized photons (Pɣ≈40%) from

coherent bremsstrahlung on thin diamond radiator.

  • Polarization parallel and perpendicular to

floor.

  • Design intensity of 108 ɣ/s in coherent peak

(Eɣ = 8.4-9 GeV)

Polarimeter

Goniometer with diamonds

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SLIDE 12

The GlueX Experiment

June 4, 2016 Meson 2016 - C.A. Meyer

12 75 m Collimator

select < 25 r polarized photons

Hall-D

Diamond Radiator

​"↑− "%→&​"↑− % Tagger Area

Photon Tagger Pair Spectrometer GlueX Spectrometer Photon Beam Dump Electron Beam Dump East ARC North LINAC Polarimeter

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SLIDE 13

GlueX Commissioning

June 4, 2016 Meson 2016 - C.A. Meyer

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Generated: April 25, 2016

Integrated Beam Time [Days]

10 5 15

Number of Events Collected / 109

10 20 30

Total Unpolarized || Polarization ⊥ Polarization

Spring 2016 run with 12-GeV electrons on thin diamond

  • radiators. Linear polarization, both perpendicular and

parallel to the earth, collected.

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SLIDE 14

GlueX Calorimeter Performance

June 4, 2016 Meson 2016 - C.A. Meyer

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Mγγ [GeV/c2]

0.00 0.05 0.10 0.15 0.20 0.25 0.30

Candidates / 2 MeV/c2

50 100 150 200 250 50 100 150 200 250 300 0.00 0.05 0.10 0.15 0.20 0.25 0.30

Candidates / 2 MeV/c2 Mγγ [GeV/c2]

Design Goal Design Goal Forward Lead Glass Calorimeter Barrel Lead-Scintillating Fiber Calorimeter

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SLIDE 15

GlueX Tracking Performance

June 4, 2016 Meson 2016 - C.A. Meyer

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Track to Wire Distance (d) [mm] 1 2 3 4 5 6 7 8 Straw Effjciency 0.0 0.2 0.4 0.6 0.8 1.0 d 8 mm Central Drift Chamber (CDC) 1 2 3 4 140 160 180 200 220 240 260 Wire Position Resolution [µm] Track to Wire Distance [mm] Forward Drift Chamber (FDC)

Design Resolution for Cathodes and Wires: 200 µm

Achieved Cathode Resolution: 150 µm

Position Resolution [µm] 200 400 600 800

Design Resolution: 150 µm

1000 Track to Wire Distance (d) [mm] 1 2 3 4 5 6 7 8 9 10 x Coordinate [mm]

  • 400
  • 200

200 0.82 0.86 0.90 0.94 0.98 3D Reconstruction Effjciency 400

Colors Index Chambers in the Third Package

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SLIDE 16

GlueX Particle Identification

June 4, 2016 Meson 2016 - C.A. Meyer

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Track Momentum [GeV/c] 0.0 0.5 1.0 1.5 2.0 2.5 3.0 β from Time of Flight 0.0 0.2 0.4 0.6 0.8 1.0 1 10 102

Positively Charged Particles

0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 0.2 0.4 0.6 0.8 1.0 1 10 102 Track Momentum [GeV/c] β from Time of Flight

Negatively Charged Particles

2 4 6 8 10 12 0.0 0.5 1.0 1.5 2.0 2.5 50 100 150 200 250 300 350 400 450

FCAL Energy / Track Momentum Track Polar Angle [degrees]

0.0 0.5 1.0 1.5 2.0 2.5 3.0 CDC dE/dx [keV/cm] 2 4 6 8 10 12 14 1 10 102 103 104

Positively Charged Particles

Track Momentum [GeV/c]

e+/e- hadrons p π/K/e p K π e K π e

Incorrect RF Bunch

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SLIDE 17

Start of Physics in GlueX

  • Initial reactions will be polarization transfer and

beam asymmetry measurements.

  • Spin-density matrix elements to understand

production mechanisms.

  • Opportunistic results from data exploration.
  • Cross section measurements.
  • Identify known mesons in PWA.
  • Move on to the search for exotic hybrids.

June 4, 2016 Meson 2016 - C.A. Meyer

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γp → (π0, η, η0)p γp → (ρ0, ω, φ)p

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SLIDE 18

Early Physics in GlueX

  • Initial reactions will be polarization transfer and

beam asymmetry measurements.

  • Spin-density matrix elements to understand

production mechanisms.

  • Opportunistic results from data exploration.
  • Cross section measurements.
  • Identify known mesons in PWA.
  • Move on to the search for exotic hybrids.

June 4, 2016 Meson 2016 - C.A. Meyer

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γp → (π0, η, η0)p γp → (ρ0, ω, φ)p

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SLIDE 19

Degree of Polarization

0.0 0.2 0.4 0.6 0.8 1.0

Energy [MeV]

2000 4000 6000 8000 10000 12000

Model Fit to Coherent Enhancement

Beam Asymmetry in ρ Photoproduction

June 4, 2016 Meson 2016 - C.A. Meyer

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  • 150 -100 -50

50 100 150

φ [degrees] dN/dφ [Arbitrary Units]

  • 150 -100 -50

50 100 150

⊥ Polarization || Polarization φ [degrees]

Lab Floor

ρ Decay Plane

ρ

π+ π−

Photon Beam Polarization Plane

φ

|| Polarization

  • 0.3
  • 0.2
  • 0.1

0.0 0.1 0.2 0.3

  • 150
  • 100
  • 50

50 100 150

φ [degrees] Asymmetry

dσ⊥ ∝ 1 − P⊥Σ cos 2φ dσk ∝ 1 + PkΣ cos 2φ PΣ cos 2φ = Nk − N? Nk + N? ~40% Polarization

Large polarization transfer to the ρ Between 100 and 1000 times the 3000 existing events from SLAC. Working with JPAC on models for analysis

Acceptance errors not included

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SLIDE 20

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π0 beam asymmetry

Beam asymmetry Σ provides insight into dominant production mechanism Understanding production mechanism critical to disentangling JPC of observed states in exotic hybrid search. From experimental standpoint easily extended to ɣp→η where there are no previous measurements!

Exchange JPC

Mathieu et al. PRD 92, 074013 Data at different beam energies

June 4, 2016 Meson 2016 - C.A. Meyer

See Adam Szczepaniak’s talk on JPAC

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SLIDE 21

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π0 model: integration with JPAC

Similar to ρ0 model, simply calculate intensity based on JPAC provided function Generate ɣp→π0p events and process through full detector simulation and reconstruction Before Spring 2016 run estimated yields for 12 hours of beam; evaluated statistical precision

Actually collected >10x more data!

Simulation from JPAC Model

  • V. Mathieu (JPAC) PRD 92, 074013

A Donnachie PRC 93, 025203 12 hours of beam: statistical errors only

Σ

June 4, 2016 Meson 2016 - C.A. Meyer

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SLIDE 22

Pseudoscalar Beam Asymmetries

June 4, 2016 Meson 2016 - C.A. Meyer

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γp → π0p γp → ηp

Preliminary Preliminary

∼ PΣπ0 cos 2φ ∼ PΣη cos 2φ

From a subset of all available data. Polarization not yet determined.

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SLIDE 23

Physics Opportunities

June 4, 2016 Meson 2016 - C.A. Meyer

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ρ’? SLAC:

PRL 53, 751 (1984)

In the ρ event sample, we can look for higher-mass vector mesons. We

  • bserve an enhancement around 1.6

GeV with significantly more statistics than existed and we should be able to measure polarization observables.

mπ+π−[GeV/c2]

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SLIDE 24

Four photon final states

June 4, 2016 Meson 2016 - C.A. Meyer

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M(4γ) [GeV/c2]

0.0 0.5 1.0 1.5 2.0 100 200 300 400 500 20 40 60 80 100 120 140 160 180 200 220

Candidates / 10 MeV/c2

0.0 0.5 1.0 1.5 2.0 2.5

M(4γ) [GeV/c2] Candidates / 10 MeV/c2 π0π0 Region ηπ0 Region f2(1270) σ/f0(980) a0(980) a2(1320)

0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0

1 10

2

10

3

10

M(γγ) for Pair 1 [GeV/c2] M(γγ) for Pair 2 [GeV/c2] ηπ0 ηπ0 π0π0

γp → pγγγγ

π0π0 ηπ0 π0η ηη

About 6% of the spring 2016 statistics from early in the run and using a very preliminary production run. Clear signals for σ, f0(980), f2(1270), a0(980) and a2(1320).

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SLIDE 25

Forward Kaon Identification

June 4, 2016 Meson 2016 - C.A. Meyer

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Beam Axis Bar Boxes Focusing Box and Readout Existing GlueX Forward Carriage GlueX DIRC Support Structure Time of Flight and Forward Calorimeter

  • Four of the BaBar DIRC bar

boxes will be installed in front of the TOF wall.

  • This combined with the
  • ther PID systems in GlueX

will allow us to fully study final states with strange quarks.

  • Strangeonium mesons and

hybrids can be studied.

  • Hyperon and cascade

baryons can be studied. Expected in 2018/2019

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SLIDE 26

GlueX Experiments

June 4, 2016 Meson 2016 - C.A. Meyer

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GlueX—Hybrid mesons/spectroscopy PR-06-102, PR-12-002 & PR-13-003 GlueX—PrimEx-eta PR-10-011 (calorimeter plug) GlueX—Pion polarizability PR-13-008 (forward muon detector) GlueX—JEF: Rare eta decays PR14-004 (calorimeter upgrade) A rating 340-540 PAC days A- rating 79 PAC Days A- rating 25 PAC Days Conditionally Approved

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SLIDE 27

GlueX Experiments

June 4, 2016 Meson 2016 - C.A. Meyer

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GlueX—Study of ω photoproduction

  • n nuclei.

Workshop held in February 2016 https://www.jlab.org/conferences/kl2016/ GlueX—Physics opportunities with a secondary KL beam Workshop held in April 2016 https://www.jlab.org/conferences/photoproduction16/ LOI 2015 LOI 2015

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SLIDE 28

Summary

  • GlueX is installed, commissioned and ready to start

physics running in Fall 2016.

  • All detector systems are near design specifications.
  • We are aggressively moving ahead on our first physics

measurements.

  • The broader program of exotic mesons is in sight.
  • Addition of kaon identification and five-times higher

intensity is planned in 2018 to allow us to cover all parts

  • f the GlueX exotic hybrid program.
  • We have an extensive program beyond exotic hybrids

and are excited to have new ideas and new collaborators.

June 4, 2016 Meson 2016 - C.A. Meyer

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