View
5
Download
0
Category
Preview:
Citation preview
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Cornell 75SLAC 75SLAC 76 (Unpublished)CERN NA14FNAL E401FNAL E687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
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3"SIGNAL" Setting (9 days)"BACKGROUND" Setting (2 days)Cornell 75SLAC 76 (Unpublished)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
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
Recommended