Upload
trevor-barnard-morris
View
243
Download
0
Tags:
Embed Size (px)
Citation preview
Transverse Spin Physics with PHENIX 1
TransverseSpin Physics with the
current PHENIX
K. Oleg EyserUC Riverside
RHIC Spin: The next decadeMay 14-16, 2010 – Iowa State University, Ames
Transverse Spin Physics with PHENIX 2
Disclaimer How do we get from now to the future?
The physics should be our main objective.
We should not measure something just because we can measure it.
This will be part summary and part outlook of how the current PHENIX can do to contribute to an exciting physics program.
A less bound perspective will follow in the next talk.
Transverse Spin Physics with PHENIX 3
Nucleon Collisions
fa
fb
σ
FFq
initialstate
hardscattering
finalstate
Sources of Asymmetries
SiversTransversityCollins
Transverse Spin Physics with PHENIX 4
Three major questions
RHIC Spin Plan 2007/2008 How do gluons contribute to the proton
spin? large x range
What is the flavor structure of the polarized sea in the nucleon?
What are the origins of transverse-spin phenomena in QCD? Transversity Connections to orbital angular momentum
Transverse Spin Physics with PHENIX 5
Input for theory… Separate Sivers and Collins
Hadron in jet
Di-hadron correlation
Transversity two-hadron interference fragmentation
Non-universality test of Sivers Drell Yan
gamma-jet
Transverse Spin Physics with PHENIX 6
Objectives Transverse spin phenomena
asymmetries at high xF
large rapidities
QCD test
separate Sivers and Collins
Flavor separated PDFsgamma-jet, pion-jetIFF for identified hadronsjet AN, direct photons
Transverse Spin Physics with PHENIX 7
From now to soon…
A. Sivers & Collins meson & hadron forward AN
B. transversity driven asymmetries interference fragmentation
analysis
C. Sivers-type asymmetries heavy flavor back-to-back hadrons AN at mid-rapidity
A. Sivers & Collins meson & hadron forward AN
B. transversity driven asymmetries interference fragmentation
analysis
C. Sivers-type asymmetries heavy flavor back-to-back hadrons AN at mid-rapidity
Transverse Spin Physics with PHENIX 8
PHENIX
Muon Arms 1.2 < | η | < 2.4 J/Ψ unidentified charged hadrons heavy flavor
Central Arms | η | < 0.35 identified charged hadrons π0, η direct photon J/Ψ heavy flavor
MPC 3.1 < | η | < 3.9 π0, η
Transverse Spin Physics with PHENIX 9
Where can we look?
pseudorapidity-4 -3 -2 -1 0 1 2 3 4
azi
muth
muon p
isto
n c
alo
rim
ete
r
muon p
isto
n c
alo
rim
ete
r
muon a
rm
muon a
rm
centralarms
Transverse Spin Physics with PHENIX 10
Forward AN
Processs contribution to pi0, eta=3.3, sqrt(s)=200 GeV
Guzey et al, PLB 603,173 (2004)
Transversity x Collins Sivers
very valuable for a global analysis
Transverse Spin Physics with PHENIX 11
Forward AN
Cluster contribution decay photon π0
direct photon
also: hadronsin muon arms
Double transversity: ATT
η < 3.3 η > 3.3
xF xF
Transverse Spin Physics with PHENIX 12
Heavy flavor
a.u
. (p
yth
ia)
di-muonxF ≈ -1
di-electronxF = 0
di-muonxF ≈ 1
200 GeV500 GeV
J/Psi single spin asymmetry production mechanism gluon dynamics larger xFlever arm?
Run6 / Run8 statistics
xF
Transverse Spin Physics with PHENIX 13
VTX & FVTX
Additional tracking -2.4 < η < 2.4 Improved J/Psi mass
resolution 100 MeV/c2
Additional tracking -2.4 < η < 2.4 Improved J/Psi mass
resolution 100 MeV/c2
Transverse Spin Physics with PHENIX 14
Where can we look?
pseudorapidity-4 -3 -2 -1 0 1 2 3 4
azi
muth
muon p
isto
n c
alo
rim
ete
r
muon p
isto
n c
alo
rim
ete
r
muon a
rm
muon a
rm
centralarms
Transverse Spin Physics with PHENIX 15
Heavy Flavorsingle leptons / no full D-meson reconstruction dominated by charm production in kinematic range no transversity (no transversity x Collins)
Transverse Spin Physics with PHENIX 16
Back-to-back jets
The Sivers effect can manifest itself as an azimuthal asymmetry in back-to-back jets in polarized p+p collisions.
Boer, VogelsangPhys. Rev. D 69, 094025
Bomhof, Mulder, Vogelsang and YuanPRD 75, 074019
)( TT kpS
jet
jetδφ
Transverse Spin Physics with PHENIX 17
Di-hadron Correlations In the central arm triggered
neutral pion
associated hadron
other possible combinations
Transverse Spin Physics with PHENIX 18
Interference fragmentation
Di-hadron asymmetry of hadron pairs:interference fragmentation
probes δq(x) x H1
Fragmentation should be universal compare with same IFF
in lepton scattering first (non-zero) results of
IFF from BELLE
21 ,
,
hh
UTA
++
++__
__qq
IFFIFF
Transverse Spin Physics with PHENIX 19
IFF at mid-rapidity
Transverse Spin Physics with PHENIX 20
A forward calorimeter
Si-W calorimeter Combines tracking with calorimetry Excellent gamma-pion separation
Transverse Spin Physics with PHENIX 21
Where can we look?
pseudorapidity-4 -3 -2 -1 0 1 2 3 4
azi
muth
muon p
isto
n c
alo
rim
ete
r
muon p
isto
n c
alo
rim
ete
r
muon a
rm
muon a
rm
centralarms
Transverse Spin Physics with PHENIX 22
FoCal x Coverage
x versus h (p+p, 500 GeV)
x coverage weak pT dependence
strong dependence complementary to
MPC
Transverse Spin Physics with PHENIX 23
photon-jet productionPRL 99, 212002 (2007)standard partonic cross sectionsmax gluon Siversmax Boer-Muldersgluonic-pole cross sections
200 GeV
Moment is dominated by quark Sivers function
Validation of framework Sign change is a
fundamental QCD prediction
Would require substantial transverse running…
Transverse Spin Physics with PHENIX 24
two dedicated trigger Resistive Plate Chamber stations per arm
approx. 1 degree pitch in azimuth
Muon Trigger Upgrade
for AL of W bosons also good for
transverse asymmetriesKang, Qiu arxiv:0903.3629v1
Transverse Spin Physics with PHENIX 25
Excursion: Drell Yan, again…
Too good to be ignored No fragmentation Separate initial from
final state effects Sivers vs. Collins
If we could choose… What is the best kinematic range? What signal/background can we achieve? What energy yields the optimum result? Which flavor is most promising?
Transverse Spin Physics with PHENIX 26
Simulation @ 500 GeV Muon pairs in different rapidity rangesall, central (|y|<1), forward (|y|>2), very forward (|y|>3)
minimum bias*
jet processesdiffractive, multiplewide rapidity (±4)very basic cuts
Drell Yanqualitative
not properly scaled≈ x10-6
Transverse Spin Physics with PHENIX 27
Very forward muons Modest upgrade
Muon detectors
Choice of technology RPC or other
Background Behind muon piston Impact on ZDC
Magnetic field Charge separation
Only in south arm
Modest upgrade Muon detectors
Choice of technology RPC or other
Background Behind muon piston Impact on ZDC
Magnetic field Charge separation
Only in south arm
Transverse Spin Physics with PHENIX 28
Simulation @ 500 GeV Electron pairs in different rapidity rangesall, central (|y|<1), forward (|y|>2), very forward (|y|>3)
minimum bias*
jet processes
diffractive, multiple
wide rapidity (±4)
very basic cuts
Drell Yanqualitative
not properly scaled≈ x10-6
Transverse Spin Physics with PHENIX 29
Electron/muon pairs PYTHIA ISUB 1 is virtual photon and Z0
not all is Drell Yan!all ISUB 1 (10M evts)
quarks e mu quarks e mu
lepton pairs (+/-)
electronsmuons
lepton pair in event
look at leptonpairs only
ɣ*decays
into
Transverse Spin Physics with PHENIX 30
Summary Different origins of spin
asymmetries Focus on what we (as in
hadron collisions) can do best
Finish current spin plan We need a thorough
investigation for future upgrades
Transverse Spin Physics with PHENIX 31
backup
Transverse Spin Physics with PHENIX 32
Heavy Flavor
pp↑→DX @LO
PRD 70,074025
Transverse Spin Physics with PHENIX 33
Forward AN Charged Hadrons
• Unidentified charged hadron AN
• Asymmetries corrected for bin sharing and interactions in magnet/absorber
• Non-zero AN persists to moderate pseudorapidity
Transverse Spin Physics with PHENIX 34
IFF Definitions
1 2
1 2
1 2
, : momenta of protons
, : momenta of hadrons
( ) / 2
: proton spin orientation
A B
h h
C h h
C h h
B
P P
P P
P P P
R P P
S
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^
1hP^^^^^^^^^^^^^^
2hP^^^^^^^^^^^^^^
AP^^^^^^^^^^^^^^
BP^^^^^^^^^^^^^^
CP^^^^^^^^^^^^^^
BS^^^^^^^^^^^^^^
pp hhX
1 2hadron plane: ,
scattering plane: ,
h h
C B
P P
P P
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^ : from scattering plane
to hadron planeR : from polarization vector
to scattering plane S
Bacchetta and Radici, PRD70, 094032 (2004)
2 CR^^^^^^^^^^^^^^
Transverse Spin Physics with PHENIX 35
BELLE IFF
8x8 m1 m2 binning
Preliminary
A. Vossen Dubna, Sept. 09
Measurement probes ( H1< )2
Non-zero and large spin-dependant FF
Preliminary