Thorsten Renk

https://www.jyu.fi/fysiikka/en/research/highenergy/urhic
Ultrarelativistic heavy ion collisions – theory group at Jyväskylä
Thorsten Renk, for the group
• Personnel
Seniors
Kari J. Eskola
Tuomas Lappi
Thorsten Renk
Postdocs
Harri Niemi
Hannu Paukkunen
Redamy Perez-Ramos
PhD students
Risto Paatelainen
Ilkka Helenius
Heikki Mäntysaari
+ 5 MSc Students
professor
Academy research fellow, QCD HIP-project leader
Academy research fellow
JYFL
HIP
Academy/HIP
Wihuri foundation  postdoc at USC, Spain 10/2014
Väisälä f. / HIP
 postdoc at Lund U., Sweden 9/2014
PANU grad. school
• Funding, averaged over the last years:
O(0.5M€/year) = JU budget 34% + Academy of Finland 38% + HIP 12%
+ private f’s 9% + PANU 7%
Our group’s history
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URHIC hydrodynamics since ’80s: prof. Ruuskanen (founder, retired in 2006)
perturbative QCD in URHIC: Eskola since 1997 (prof. in 2007)
URHIC jet simulations: Renk since 2005
small-x (CGC) studies: Lappi since 2009
• Initiative for the local ALICE exp. group 1998 from Äystö, Ruuskanen, Kajantie
• URHIC theory part of the Helsinki Institute of Physics (HIP) Theory Programme
since 2002: currently QCD project by Lappi
Close local collaboration with
• particle theory & cosmology groups
teaching + student recruitment
• JYFL/HIP ALICE group
+ physics + common weekly seminars
Strong international collaboration
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Individual researchers from Santiago de C., Frankfurt, Duke, Saclay, BNL, VECC,…
Theory collaborations: Hard Probes, TECHQM & JET collaborations, …
EU networking: TORIC/TURIC WPs of Hadronphysics1,2,3,…
Physics planning of future EIC (USA), LHeC, FCC
URHIC physics
• Testing the strong interaction part of the Standard Model
- determine the properties of elementary-particle QCD matter, Quark-Gluon Plasma
- understand QCD collision dynamics at high energies and densities
• Our long-term goal
a simultaneous theory-analysis of various URHIC-observables, based on which the
QGP properties can be determined from CERN-LHC and BNL-RHIC measurements
• Methods
perturbative QCD, high-energy QCD (“CGC”), relativistic hydrodynamics,
MC simulations, supercomputing at CSC
Initial state
Hydrodynamic expansion
photons
decoupling
jets
• We are wordwide one of the few theory groups able to address
this full evolution and different probes with ”in-house” expertise!
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Examples of our world-expertise:
1. Perturbative QCD analysis of quark and gluon densities in nuclei: nuclear PDFs
our pioneering work EKS98 is a standard reference [Eskola, Kolhinen, Salgado, Eur.Phys.J.C9:61, 1999 – 622 cit.]
our EPS09 NLO is the current state of the art [Eskola, Paukkunen, Salgado, JHEP 0904:065,2009 – 360 cit.]
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Nuclear modifications of PDFs
We have quantified the unknown:
using the EPS09 error sets, one can compute
how these uncertainties propagate into
hard-process cross sections
in A+A, p+A, d+A, … collisions
 Many applications at RHIC & LHC!
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EPS09s: spatially dependent nPDFs
[Helenius, Eskola, Honkanen, Salgado, JHEP 1207 (2012) 073]
[dijets; CMS at QM14]
”ridge”
2. Small-x physics
= QCD in the high-E limit  gluon saturation & CGC
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The “ridge” in p+p collisions at the LHC
 QCD origin for the ridge correlation, observed in highmultiplicity p+p events, in the Color-Glass Condensate
framework [Dumitru, Dusling, Gelis, Jalilian-Marian, Lappi,
Venugopalan, Phys. Lett. B697 (2011) 21 – 99 cit.]
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J/Psi in ultraperipheral Pb+Pb at LHC
[Lappi, Mäntysaari, Phys.Rev. C87 (2013) 032201]
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BK-RGE phenomenology
from HERA to particle production at the LHC
[Lappi, Mäntysaari, Phys. Rev. D88 (2013) 114020]
[ALICE, Eur.Phys.J. C73 (2013) 2617]
[ALICE at QM2014]
3. Hydrodynamical simulations
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Event-by-event MC simulations
[Holopainen, Eskola, Niemi,
Phys.Rev. C83 (2011) 034901 –118 cit.]
explain the measured azimuthal
momentum asymmetry in Au+Au at RHIC
 NPA Young Scientist Award, best theory talk in QM11
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Limits for QCD matter viscosity
 Developed the EKRT pQCD+saturation model for
computing the QGP initial densities for hydro
[Paatelainen et al, Phys.Lett. B731 (2014) 126-130]
 multiobservable analysis after viscous hydro
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Kinetic theory foundations of hydro
[Denicol, Niemi, Molnar, Rischke, Phys.Rev.D85(2012) 114047]
4. Hard and electromagnetic probes
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Thermal photons in A+A vs hard pQCD photons
[Chatterjee, Holopainen, Helenius, Renk, Eskola,
Phys.Rev. C88 (2013) 034901]
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Jets & high-pT hadrons
MC simulations of in-medium parton showers
 YaJEM [Renk, Phys.Rev. C78 (2008) 034908]
Hydro w. QCD-based initial
state modeling
LHC
p+p, pQCD
Jet quenching
[Renk, Holopainen, Paatelainen,
Phys.Rev. C84 (2011) 014906]
Renk, Phys.Rev. C87 (2013) 2, 024905
We are internationally well connected and visible
e.g. at the Quark Matter 2014 conference (Darmstadt 5/2014; ~900 participants)
we had
• 7 participants
• 1 plenary talk (Niemi; hydro review)
• 3 parallel talks (Lappi, Paukkunen, Renk)
• 3 posters (Mäntysaari, Paatelainen, Paukkunen/Helenius)
• invited lectures at the Student Day (Renk)
• a member in the IAC (Eskola)
and Tuomas Lappi received the 2014 Zimanyi Medal
= the most prestigious international
young researcher award in this field