ICPAQGP, Kolkata, February 2-6, 2015 Itzhak Tserruya PHENIX
highlights
Slide 2
Introduction Itzhak Tserruya ICPAQGP, Kolkata, February 2-6,
2015 2 RHIC is a unique machine for its versatility Can collide any
species from p up to U, at any energy from the top energy of s NN =
200 GeV down to 7 GeV PHENIX capitalizes on this versatility
performing systematic studies of observables as function of system
size and colliding energy This talk will focus on recent PHENIX
results on these studies
Slide 3
Outline Introduction Small vs large systems: change of
paradigm? Long range correlations in d, 3 He + Au v 2 in d, 3 He +
Au HBT radii in d+Au, Cu+Cu HF and J/ R AA in d+Au, Cu+Cu Lower
energies HBT radii vs energy dN ch /d scaling v 2 energy dependence
HF R AA vs energy Photons Summary 3
Slide 4
Small systems: paradigm change? Itzhak Tserruya ICPAQGP,
Kolkata, February 2-6, 2015 4 p+p: reference baseline p,d+A: System
size too small for quark matter formation Reference for cold
nuclear matter effects Is that so? Many features seen in A+A
collisions are also seen in high multiplicity p,d+A
collisions:
Slide 5
Small systems: paradigm change? Small systems: paradigm change?
Itzhak Tserruya ICPAQGP, Kolkata, February 2-6, 2015 5 p+p:
reference baseline p,d+A: System size too small for quark matter
formation Reference for cold nuclear matter effects Is that so?
Many features seen in A+A collisions are also seen in high
multiplicity p,d+A collisions: Long range correlations in d, 3
He+Au
Slide 6
Ridge in small systems at RHIC Long-range near-side peak
clearly visible in central d+Au collisions Not present in minimum
bias p+p collisions Min bias p+pCentral d+Au Two particle
correlations measured over a large | | > 2.75 gap (charged track
in central arm and tower hit in forward calorimeter)
arXiv:1404.7461 Central 3 He+Au Long-range near-side peak clearly
visible in central d+Au and central 3 He+Au collisions Not present
in minimum bias p+p collisions
Slide 7
and at LHC 7 ICPAQGP, Kolkata, February 2-6, 2015 Long-range
near-side peak clearly visible in high multiplicity p+Pb collisions
as observed in AA collisions at RHIC and LHC CMS p+Pb s NN =5.02
TeV N trk > 110STAR Au+Au central s NN =200 GeV PLB 718, 795
(2013)PRC 80, 064912 (2009) very similar to AA Itzhak Tserruya
Slide 8
Long-range correlations in d+Au No ridge in d-going direction.
Shape of correlation changes with centrality Ridge seen only in
Au-going direction. Strong centrality dependence Peripheral
collisions: very similar correlations in d-going and Au-going sides
arXiv:1404.7461
Slide 9
Ridge in central 3 He+Au Long-range correlations seen on both
Au-going and 3 He-going sides 9Itzhak Tserruya ICPAQGP, Kolkata,
February 2-6, 2015 Hydro can explain and reproduce the ridge Also
CGC effective field theory (initial state gluon saturation) can
explain the ridge (Phys. Rev. D87, 094034 (2013)).
Slide 10
Small systems: paradigm change? Small systems: paradigm change?
Itzhak Tserruya ICPAQGP, Kolkata, February 2-6, 2015 10 p+p:
reference baseline p,d+A: System size too small for quark matter
formation Reference for cold nuclear matter effects Is that so?
Many features seen in A+A collisions are also seen in high
multiplicity p,d+A collisions: Long range correlations in d, 3
He+Au Flow in d, 3 He+Au
Slide 11
Flow in small systems at RHIC 11 ICPAQGP, Kolkata, February
2-6, 2015 Mass ordering seen in d+Au v 2 Data consistent with
viscous hydrodynamics (using /s =1/4) at p T
Slide 12
and at the LHC 12 ICPAQGP, Kolkata, February 2-6, 2015 very
similar to AA PLB 726, 164 (2013)PRC 72, 014904 (2005) ALICE Itzhak
Tserruya Flow observed in small systems at RHIC and LHC Similar
magnitude and mass ordering as observed in AA collisions
Slide 13
Small systems: paradigm change? Small systems: paradigm change?
Itzhak Tserruya ICPAQGP, Kolkata, February 2-6, 2015 13 p+p:
reference baseline p,d+A: System size too small for quark matter
formation Reference for cold nuclear matter effects Is that so?
Many features seen in A+A collisions are also seen in high
multiplicity p,d+A collisions: Long range correlations in d, 3
He+Au Flow in d, 3 He+Au HBT radii in d+Au
Slide 14
14 HBT radii scale with size arXiv:1410.2559 PHENIX Au+Au and
Cu+Cu: HBT radii scale linearly with initial transverse size ALICE
Pb+Pb : same behavior
Slide 15
15 ICPAQGP, Kolkata, February 2-6, 2015 also in small systems a
HBT radii scale linearly with the initial transverse size from
small (d+Au, p+Pb) to large (Au+Au, Pb+Pb) systems at RHIC and LHC.
Imply radial expansion in small systems and final state interaction
arXiv:1404.5291 Itzhak Tserruya
Slide 16
Small systems: paradigm change? Small systems: paradigm change?
Itzhak Tserruya ICPAQGP, Kolkata, February 2-6, 2015 16 p+p:
reference baseline p,d+A: System size too small for quark matter
formation Reference for cold nuclear matter effects Is that so?
Many features seen in A+A collisions are also seen in high
multiplicity p,d+A collisions: Long range correlations in d, 3
He+Au Flow in d, 3 He+Au HBT radii in d+Au HF and J/ R AA in d+Au
and Cu+Cu
Slide 17
HF R AA system-size dependence Itzhak Tserruya ICPAQGP,
Kolkata, February 2-6, 2015 17 PRC 90, 034903 (2014) Smooth
evolution of HF R AA from enhancement in small systems to
suppression in large systems
Slide 18
18 J/ system-size dependence PRC 90, 064908 (2014) Similar
suppression for smaller (CuCu) and larger (AuAu) systems. PRL 101,
122301 (2008) Similar suppression in Cu+Au (Au-going direction) and
Au+Au Stronger suppression in Cu+Au (Cu-going direction) opposite
of expected trend if suppression is prop to particle density
HBT vs. collision energy Itzhak Tserruya ICPAQGP, Kolkata,
February 2-6, 2015 20 PHENIX, STAR and ALICE results combined
Non-monotonic behavior of R out 2 R side 2 (proportional to
emission duration and (R side -2R)/ R long (related to medium
expansion velocity). softening of equation of state near the CEP?
arXiv:1410.2559
Slide 21
dN ch /d scaling Itzhak Tserruya ICPAQGP, Kolkata, February
2-6, 2015 21 N part scalingN quark scaling
Slide 22
dN ch /d scaling Itzhak Tserruya ICPAQGP, Kolkata, February
2-6, 2015 22 N part scalingN quark scaling Normalize highest
multiplicity point at each energy to 1 N part scaling works well at
low energies N quark scaling works well at high energies Transition
at ~ 39 GeV.
Slide 23
v 2 in Cu+Cu and Au+Au collisions at s NN =62.4 and200 GeV 23
arXiv:1412.1043 Au+Au Cu+Cu Almost no difference in v 2 at 200 and
62 GeV in Au+Au and Cu+Cu
Slide 24
v 2 energy dependence Itzhak Tserruya ICPAQGP, Kolkata,
February 2-6, 2015 24 Flow saturates at s NN = 39 200 GeV
Significant decrease at s NN = 7.7 GeV
Slide 25
R AA vs energy Itzhak Tserruya ICPAQGP, Kolkata, February 2-6,
2015 25 Central Cu+Cu: Onset of suppression between 22.4 and 62.4
GeV Central Au+Au: Onset of suppression at energies lower than 39
GeV But very different N part Cu+Cu PRL 101, 162301 (2008) Au+Au
PRL 109, 152301 (2012) N part 90-98 N part 315-325
Slide 26
HF R AA in Au+Au Strong suppression Large v 2 Enhancement
opposite to energy loss models Same v 2 within uncertainties
arXiv:1405.3301PRC 84, 044905 (2011) 200 GeV62.4 GeV 26
Slide 27
Photons Photons Itzhak Tserruya ICPAQGP, Kolkata, February 2-6,
2015 27
Slide 28
Direct photons Itzhak Tserruya ICPAQGP, Kolkata, February 2-6,
2015 28 New measurement using external conversion of real photons
Consistent with previous result Extend range to lower p T, higher
statistics arXiv:1405.3940 v 2 remains a challenge for theory. New
v 3 data provide additional constraint
Slide 29
Direct photons excess: Centrality dependence Itzhak Tserruya
ICPAQGP, Kolkata, February 2-6, 2015 29 Subtract N coll scaled p+p
spectrum excess photon yield Fit excess photon yield with Y = A
exp(-p T /T) Inverse slope T independent of centrality
arXiv:1405.3940 Integrated excess yield scale as dN/dy = B N part
with =1.480.080.04
Slide 30
Future Future Itzhak Tserruya ICPAQGP, Kolkata, February 2-6,
2015 30
Slide 31
The future: sPHENIX Itzhak Tserruya ICPAQGP, Kolkata, February
2-6, 2015 31 arXiv:1501.06197 Excellent jet, dijet, h, -jet
quarkonia capabilities Designed to be the basis for a future eIC
detector DOE Science Review in July 2014 1.5 T BaBar magnet being
moved to BNL
Slide 32
Summary Many phenomena observed in A+A collisions are also seen
in small systems p,d+A. Interesting features observed at low
energies. Direct photons remain a puzzle sPHENIX 32 ICPAQGP,
Kolkata, February 2-6, 2015 Itzhak Tserruya
Slide 33
Other recent PHENIX results Itzhak Tserruya ICPAQGP, Kolkata,
February 2-6, 2015 33 arXiv:1412.1038 HF and J/ in d+Au at 200 GeV
in Au+Au J/ in U+U, Au+Au, Cu+Cuv 2, v 3, v 4 in Au+AuDark Photons
arXiv:1404.2246 arXiv:1409.0651