MAEDI-JSPS Sakura program●●●

A bilateral cooperative program between
France and JapanTo form sustained networks evolved fromindividual scientist exchanges including
young scientists
France {Marquet, Gelis, Iancu, Schoeffel, Soyez, Royon,Kohara, Petreska, Saimpert }●Japan {Fujii, Hatta, Itakura, Nara, Sako, Yamazaki,
Hagiwara, Taya, Zhou }JSPS Sakura, 29-Oct-2016

H. FujiiUpdateof
heavy quark production in pA
H. Fujii(U Tokyo, Komaba)

HF and K. Watanabe, NPA915(2013)1; 920(2013)78; 951(2016)45

Outline●Introduction●Heavy quark production from CGC●

Numerical results– J/y– D meson– decay leptons●Discussion & Summary

JSPS Sakura, 29-Oct-2016

H. Fujii

Parton saturation●Dense partonic system at small x ischaracterized with the new scale, Qs2
Stasto, Geloc-Bienat, Kwiecinski
PRL 86 (2001) 596

ep

t = Q2/Qs2
JSPS Sakura, 29-Oct-2016

H. Fujii

Parton saturation●

Recombination of partons becomes important at
Phase space density●

suggesting a scale, below which saturation operates,●For a nucleus, atomic number enhances the scale:JSPS Sakura, 29-Oct-2016

H. Fujii

Phase diagram

JSPS Sakura, 29-Oct-2016

H. Fujii(c) Gelis

Classic evidence at RHIC
●Saturation is consistent with suppressed
particle production in dA, compared to pp,
at forward rapidity
BRAHMS,
Phys.Rev.Lett.93:242303,200
4

JSPS Sakura, 29-Oct-2016

H. Fujii

Heavy quark production in pA●

Why pA?
– to study saturation effects, enhanced by big A●

Why heavy quark?
– produced from gluons– can probe saturation Qs (～ mQ)– computed in pQCD as mQ ≫ L

JSPS Sakura, 29-Oct-2016

H. Fujii

QCDQuark pair production in large Nc●kT-factorization (for small x1,2)●Hybrid formula (for large x1 and small x2)●probe the dense gluons through 3pt func.

JSPS Sakura, 29-Oct-2016

H. Fujii

Blaizot-Gelis-Venugopalan 2002
HF-Watanabe 2013

Dipole amplitude●

Wilson line - effective d.o.f.

●

BK evolution & I.C. constained by DIS data●

“gluon dist.” (incl. higher twists):
2

φ(k , y) = k F.T. N(r , y)
JSPS Sakura, 29-Oct-2016

H. Fujii

Choice of Qs for a nucleus
Qs0A2 = c A1/3 Qs02 = ( 3?, 6? ) Qs02●

Effective Qs2 averaged over impact parameter●c=0.5 is preferred for heavy nuclei

Dusling, et al., NPA836 (2010), 159
JSPS Sakura, 29-Oct-2016

H. Fujii

Evolution of dipole●

Non-linearity leads to a universal shape of f●

More recombination in dense target– gluon suppression in heavy nuclei

JSPS Sakura, 29-Oct-2016

H. Fujii

Numerical results
Quarkonium●

JSPS Sakura, 29-Oct-2016

H. Fujii

RpA for J/y at the LHC●Color evaporation model –Q

2s0A=(4-6)Q

2s0
ALICE, 1404.1615

ALICE, 1308.6726

JSPS Sakura, 29-Oct-2016

H. Fujii

HF, Watanabe, NPA915,1, 2013

RpA for J/y at the LHC●

Color evaporation model Qs0A2 = 4,6 Qs0A2
Qs0A2 = 3 Qs0A2forward

JSPS Sakura, 29-Oct-2016

H. Fujii

HF, Watanabe, NPA915,1 (2013);
NPA951, 45 (2016)

RpA for J/y at the LHC●Color evaporation model Qs0A2 = 4,6 Qs0A2

Qs0A2 = 3 Qs0A2 mid-rapidity

JSPS Sakura, 29-Oct-2016

H. Fujii

HF, Watanabe, NPA915,1 (2013);
NPA951, 45 (2016)

Numerical results
D meson●

JSPS Sakura, 29-Oct-2016

H. Fujii

RpA for D at the LHC●using frag. fn.
ALICE, 1310.1714●

Qs0A2 = 4,6 Qs0A2
JSPS Sakura, 29-Oct-2016

H. Fujii

HF, Watanabe, NPA920 (2013);
NPA951, 45 (2016)

RpA for D at the LHC●

At mid rapidity
ALICE, 1310.1714

Qs0A2 = 3 Qs0A2

better agreement

Qs0A2 = 6 Qs0A2
JSPS Sakura, 29-Oct-2016

H. Fujii

HF, Watanabe, NPA920 (2013);
NPA951, 45 (2016)

RpA for D at the LHC●at forward rapidity

Qs0A2 = 6 Qs0A2

y=-1...0y=2...3.5

HF, Watanabe, NPA920 (2013)
JSPS Sakura, 29-Oct-2016

H. Fujii

RpA for D at the LHC●at forward rapidity

Qs0A2 = 6 Qs0A2

y=-1...0y=2...3.5

y=2.5 ...4

HF, Watanabe, NPA920 (2013)
JSPS Sakura, 29-Oct-2016

H. Fujii

LHCB-CONF-2016-003

Numerical results
Decay leptons●

JSPS Sakura, 29-Oct-2016

H. Fujii

Decay leptons from D at RHIC●

Not inconsistentRHIC

Qs0A2 = 3 Qs0A2

HF, Watanabe, NPA951 (2016)
JSPS Sakura, 29-Oct-2016

H. Fujii

Decay leptons from D at the LHC●

Not inconsistent, but systematically lower
than the data
LHCQs0A2 = 3 Qs0A2

HF, Watanabe, NPA951 (2016)
JSPS Sakura, 29-Oct-2016

H. Fujii

Discussions●Results with Qs0A2 ~ 3Qs0p2 is moreconsistent to data●

Optical Glauber model Ducloue et al. in effectcorresponds to similar value of Qs0A2●

Fluctuations in centrality is large in pA●Should use Monte Carlo to treat a nucleus

JSPS Sakura, 29-Oct-2016

H. Fujii

Summary●

Updated results with Qs0A2 ~ 3Qs0p2 , which value
is consistent with nDIS, describe the data on– J/y,●D mesons, decay leptons

Monte Carlo description for pA seems important– we plan to implement it

JSPS Sakura, 29-Oct-2016

H. Fujii

JSPS Sakura, 29-Oct-2016

H. FujiiThank you!
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Thank all of you for gathering at Komaba
today.
I hope the discussions today help yourresearch tomorrow.
Hope to expand the collaboration between
France and Japan in our field.
Look forward!

JSPS Sakura, 29-Oct-2016

H. Fujii