ERR: E12-16-007 (Hall C) OVERVIEW, DETECTOR, COLLABORATION

Sylvester Joosten sylvester.joosten@temple.edu

JLab ERR for E12-16-007, June 2017

This work is supported in part by DOE grant DE-FG02-94ER4084

Discovery of the LHCb charmed “pentaquark” Pc

2

⇤b ! ⇤⇤J/ ! (K�p)J/

⇤b ! K�Pc ! K�(pJ/ )

⇤b ! K�pJ/ Aaij, R, et. al (LHCb) PRL 115-7 (2015)

wide: Pc(4390) (9σ)

2 Pc states needed to describe results

narrow: Pc(4450) wide: Pc(4380)

spin/parity either: 5/2+, 3/2- (most likely!) 5/2-, 3/2+ 3/2-, 5/2+

narrow: Pc(4450) (12 σ)

3

[GeV]γE10 15 20

[nb]

σ2−10

1−10

1

10

210

310Cornell 75

SLAC 75

SLAC 76 (Unpub.)

2-gluon fit

Pc?

P c

s − channel

γ J/ ψ

(a)

P c

u − channel

γ J/ ψ

(b)P’P

P P’

s-channel u-channel

Signal�p ! J/ p

Access through near-threshold photo-production of J/ψ

[GeV]γE10 210 310 410 510 610

[nb]

σ

2−10

1−10

1

10

210

310

Cornell 75SLAC 75SLAC 76 (Unpublished)CERN NA14FNAL E401FNAL E687

)*γH1 Combined ()*γZEUS Combined (

)*γLHCb 2014 (

γJ/Ψ

P

e−

e+

P’

c

c

t-channel

Background

4

”pentaquark” Setting (9 days): minimizes accidentals and maximizes signal/background:

HMS: 34o, 3.25 GeV electrons SHMS: 13o, 4.5 GeV positrons

”t-channel” Setting (2 days): precise determination of the t-channel background

HMS: 20o, 4.75 GeV electrons SHMS: 20o, 4.25 GeV positrons

Setup similar to E-05-101(WACS) 50μA electron beam at 10.7 GeV (or 11 GeV) 9% copper radiator 15cm liquid hydrogen target total 10% RL

Standard Detector Package, Radiator Well Understood

To beamdump

1

3

D

Q

Q

Q

Incident

beam

Hydrogen

target

e-

Detector Stacks:

Tracking/ Timing:

1. Drift Chambers

2. Hodoscopes

3. Gas erenkov

4. Lead Glass Calorimeter

2

2

4

Particle ID:

9% Cu Radiator

D

Q

SHMS

HB

Argon/N

eon Cere

nkov

HGC

S1XS1Y

AGC

DC1

DC2

S2X

S2YLGC

A1

C4F10

Cere

nkov

12

2

3

1

4

QQ

HMS

e+

electron in HMS

positron in SHMS

E12-16-007: Pc search at Hall C�p ! J/ p

2 settings

5

E12-16-007: Pc search at Hall C

[GeV]-e+eM3 3.02 3.04 3.06 3.08 3.1 3.12 3.14 3.16 3.18 3.2

Arbi

trary

Uni

ts

0

2

4

6

8

reconstructed J/ψ mass: σ = 5 MeV (FWHM: 12MeV)

Photon energy fully constrained by the reconstructed J/ψ

[GeV]γE8 8.5 9 9.5 10 10.5 11 11.5 12

[nb]

σ

0

1

2

3"SIGNAL" Setting (9 days)"BACKGROUND" Setting (2 days)Cornell 75SLAC 76 (Unpublished)

(5% coupling)c with PψJ/

Projected ResultsTo beamdump

1

3

D

Q

Q

Q

Incident

beam

Hydrogen

target

e-

Detector Stacks:

Tracking/ Timing:

1. Drift Chambers

2. Hodoscopes

3. Gas erenkov

4. Lead Glass Calorimeter

2

2

4

Particle ID:

9% Cu Radiator

D

Q

SHMS

HB

Argon/N

eon Cere

nkov

HGC

S1XS1Y

AGC

DC1

DC2

S2X

S2YLGC

A1

C4F10

Cere

nkov

12

2

3

1

4

QQ

HMS

e+

electron in HMS

positron in SHMS

Radiator Position

6

SHMS upstream acceptance to almost 100 cm at 13o

radiator needs to be upstream by >1m (outside of the target chamber), no additional shielding needed ensure we don’t hit flow diverters of the target and entrance cylinder to the target (0.5in opening) Assuming a raster of ± 1 mm, multiple scattering of ±2.35 mm (within current target parameters)

More details in next talk by Mark Jones!

7

Particle Identification

(GeV) pHMS pSHMS

#1 3.25 4.5#2 4.75 4.25

Momentum Settings

Do not need SHMS noble gas detector Can be replaced by vacuum snout

Heavy gas detector used with shower in both arms Can use any of the available gasses

(atm) pressure (HMS)

pressure (SHMS)

C4F10 <0.2 <0.2

N2/CO2 <0.5 <0.5

Gas Pressure Requirements

C4F10

CO2

Background: single e± and π± tracks

8

electron rate estimated using CTEQ5, cross checked with F1F209 positron rate estimated using EPC combined with a background program from E94-010 coincidence rate < 10-5 Hz (50ns trigger window)pion rates estimated using Wiser Assuming a pion rejection > 103 from the Cherenkov + Calorimeter, coincidence rate ~ 10-5 Hz

Accidental Rate < 10-2 x Signal Rate NEGLIGIBLE!

Invariant Mass Acceptance for Accidentals

9

Reconstructed invariant mass range for accidentals much wider than J/ψ mass resolution

-e+eM2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8

Arbi

trary

Uni

ts

3−10

2−10

1−10

1

10

210

310

410 "SIGNAL" Setting"BACKGROUND" Setting

ψReconstructed J/

to scale!

Run Plan

10

Total Approved Beam Time: 11 days (264h), 10.7 GeV (or 11 GeV), 50μA, Hall C

Run Plan: 1. t-channel “BACKGROUND”: 40 hours 2. radiator out: 8 hours (longer if needed) 3. main “SIGNAL” measurement: 216 hours

11 days, standard equipment!

Collaboration Readiness

11

57 collaborators across 13 institutions Dedicated workforce from the Temple University group:

Burcu Duran (PhD Student) Melanie Rehfuss (PhD Student) Sylvester Joosten (Postdoc) Michael Paolone (Research Professor) Nikos Sparveris (Professor) Zein-Eddine Meziani (Professor)

Physics Division Liaison: Dave Mack

Only 11 days: plenty of staffing available

Documentation

12

Experiment uses standard equipment + radiator

New OSP to be created for radiator

Will use standard COO, ESAD, OSPs and operation

manual

Will get RSAD from RadCon

Physics Division Liaison: Dave Mack

Summary

13

High impact experiment will either confirm Pc resonance, or strongly exclude its existence

Straightforward experiment, able to run early with a standard Hall C package Radiator well understood, radiation levels under control (see next talk) Plenty of workforce available

Dedicated personal from Temple University Supported by JLab staff

Standard documentation, supplemented with OSP for radiator