FIRST THOUGHTS ABOUT EP/EA COLLISIONS AT PHENIX 1 E.C. Aschenauer PheniX & STAR meet EIC
Feb 22, 2016
1
FIRST THOUGHTS ABOUT EP/EA COLLISIONS AT PHENIX
E.C. Aschenauer PheniX & STAR meet EIC
E.C. Aschenauer PheniX & STAR meet EIC 2
Physics Topics unpolarised and polarised inclusive physics
detect only the scattered lepton F2 and FL for proton and nuclei, g1 and g2 for proton / He-3
d2σ empNC
dxdQ2 =2pαem2 Y+
xQ4 (F2 −y2Y+
FL±Y−Y+
xF3)
q(x, Q2 )+ q(x,Q2 ) g(x,Q2 ) q(x, Q2 )−q(x,Q2 )
antishadowing“sweet” spotR=1
shadowingLHC h=0RHIC h=3
Assumptions: 10GeV x 100GeV/n
√s=63GeV Ldt = 4/A fb-1
equiv to 3.8 1033 cm-2s-1
T=4weeks; DC:50% Detector: 100% efficient
Q2 up to kin. limit sx Statistical errors only
Note: L~1/A smearing effects can be significant
E.C. Aschenauer PheniX & STAR meet EIC 3
Physics Topics unpolarised and polarised inclusive physics
detect only the scattered lepton F2 and FL for proton and nuclei, g1 and g2 for proton / He-3
d2σ empNC
dxdQ2 =2pαem2 Y+
xQ4 (F2 −y2Y+
FL±Y−Y+
xF3)
q(x, Q2 )+ q(x,Q2 ) g(x,Q2 ) q(x, Q2 )−q(x,Q2 )
Lets get a feeling for systematic uncertainties: 1% energy-to-energy normalization low detector smearing will be crucial
tracking vs. calorimetry 1 - 2% vs. 5 - 10%
FL for fixed electron energy (4GeV)and proton energies:50, 70, 100, 250 GeVLuminosity: 4fb-1 each setting
E.C. Aschenauer PheniX & STAR meet EIC 4
Physics Topics unpolarised and polarised inclusive physics
detect only the scattered lepton F2 and FL for proton and nuclei, g1 and g2 for proton / He-3
d 2σ
dΩdE '~LmνΩ
mν
W mν =−gmνF1 −
pm pν
νF2 +
iνe mνλσqλσσ g1 +
iν 2
e mνλσqλ (p⋅qσσ −σ⋅qpσ )g2
Integrated Lumi: 5fb-
1
Same issues with detectorresolution as F2 and FLin addition need to reduce systematics due to polarisation
E.C. Aschenauer PheniX & STAR meet EIC 5
Kinematics
x
Q2
E.C. Aschenauer PheniX & STAR meet EIC 6
e’ Kinematics Lets concentrate on 4GeV lepton energy
electron beam “replaces” yellow hadron beamProton Energy
50 GeV 100 GeV 250 GeV
4x50
pe: 0-1 GeV pe: 1-2 GeV pe: 2-3 GeV pe: 3-4 GeV
e-p/A
180o 0o
E.C. Aschenauer PheniX & STAR meet EIC 7
Hadron Kinematics
4x100
4x250
4x250
4x1004x50
4x50
E.C. Aschenauer PheniX & STAR meet EIC 8
Diffractive Physics: p’ kinematics
4 x 100
t=(p4-p2)2 = 2[(mpin.mpout)-(EinEout - pzinpzout)]
4 x 50
4 x 50
4 x 250
?
Diffraction:
9E.C. Aschenauer PheniX & STAR meet EIC
Current PHENIX Detector at RHICMPC 3.1 < | h | < 3.9 2.5o < Q < 5.2o Muon Arms 1.2 < | h | < 2.4 South: 12o < Q < 37o
North: 10o < Q < 37o
Central Arms | h | < 0.35 60o < Q < 110o
e-
electrons will not make it to the south muon arm to much material
E.C. Aschenauer PheniX & STAR meet EIC 10
What will the current PheniX see4x
100
pe: 0-1 GeV pe: 1-2 GeV pe: 2-3 GeV pe: 3-4 GeV
4x100 4x100
Current PheniX detector not really useable for
DISacceptance not matched to DIS kinematics
E.C. Aschenauer PheniX & STAR meet EIC 11
HCALEMCAL
Preshower
How should a ePheniX look like Coverage in |h| =< 3 0.1 < Q2 < 100 (5o – 175o)
need an open geometry detector planes for next decadal plan
replace current central detector with a new one covering |h| =< 1 replace South muon arm by a endcap spectrometer able to do DY at |h| > 2.5, preferable 3 < |h| < 4
40cm
2T SolenoidEMCAL
HCAL
IPSilicon TrackerVTX + 1 layer
Silicon TrackerFVTX
1.2 < h < 2.7 8o < q < 37o
North Muon Arm
at least 1.5m
could be ILC-type HCAL with m-ID
might need a RICHfor HI physics or PID
5o @ 2m 17.4 cm dy
E.C. Aschenauer PheniX & STAR meet EIC 12
Questions which need answers is inclusive physics all we want to do? do we want to run through at all stages of eRHIC from
4x250 to 20x250 measuring luminosity for ep/eA symmetric vs. asymmetric collisions
for ep/eA collisions the IP would be much better not in the center of the detector but shifted to negative z
Problem silicon detectors: massive support material in the acceptance
material budget in the RHIC detectors momentum resolution critical for precision inclusive physics material and size of beam pipe