Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x
-
Upload
gwendolyn-leblanc -
Category
Documents
-
view
23 -
download
0
description
Transcript of Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x
![Page 1: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/1.jpg)
04/19/23 1
Mapping the Phase Structure of Cold Nuclei-- Gluon Saturation at small-x
Feng Yuan
Lawrence Berkeley National Laboratory
Refs: Mueller, Xiao, Yuan, to be published;
Stasto, Xiao, Yuan, arXiv:1109.1817;
Dominguiz, Xiao, Yuan, PRL 106, 022301 (2011);
Marquet, Dominguiz,Xiao,Yuan, PRD83, 105005 (2011)
![Page 2: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/2.jpg)
Outlines
Introduction Sudakov double logarithms in hard
processes Two-particle correlations as probe for
the phase structure of cold nuclei
04/19/23 2
![Page 3: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/3.jpg)
QCD dynamics in cold nuclei
Inclusive observables DIS structure functions P+Ah+x
Gluon density in integral form or limited access to the kt-dependence
Full exploration of the dynamics needs kt-dependence in hard processes
04/19/23 3
![Page 4: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/4.jpg)
Kt-dependent observables
Hard processes probe the kt-dependent gluon distributions directly
Saturation phenomena manifest in the observables
04/19/23 4
CSS
PJ>>KT
KT
![Page 5: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/5.jpg)
5
Sudakov Double Logarithms
Differential cross section depends on Q1, where Q2>>Q1
2>>2QCD
We have to resum these large logs to make reliable predictions QT: Dokshitzer, Diakonov, Troian, 78; Parisi Petronzio,
79; Collins, Soper, Sterman, 85 Threshold: Sterman 87; Catani and Trentadue 89
![Page 6: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/6.jpg)
6
Collins-Soper-Sterman Resummation Large Logs are re-summed by solving the energy
evolution equation of the TMDs
K and G obey the renormalization group eq.
The large logs will be resummed into the exponential form factor
A,B,C functions are perturbative calculable.
![Page 7: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/7.jpg)
Sudakov resummation at small-x
Take massive scalar particle production p+A->H+X as an example to demonstrate the double logarithms, and resummation
04/19/23 7
p H,MH
WW-gluon distribution
A
![Page 8: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/8.jpg)
Explicit one-loop calculations
04/19/23 8
Collinear divergence DGLAP evolution Small-x divergence BK-type evolution
Dominguiz-Mueller-Munier-Xiao, 2011
![Page 9: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/9.jpg)
Final result Double logs at one-loop order
Collins-Soper-Sterman resummation
04/19/23 9
![Page 10: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/10.jpg)
Comments Sudakov double logs can be re-summed
consistently in the small-x formalism Kinematics of double logs and small-x
evolution are well separatedSoft vs collinear gluons
If Qs is small, back to dilute region
If Qs is large (~Q), we can safely neglect the Sudakov effects
04/19/23 10
![Page 11: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/11.jpg)
Effective kt-factorization is formulated
In forward region of dAu collisions at RHIC and pA at LHC, Qs is large enough to neglect the Sudakov effects
Di-jet correlations in pA
04/19/23 11
![Page 12: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/12.jpg)
Central dAu collisions η1~η2~3.2
Q2sA~0.85A(1/3) Qsp
2
GBW model
No Sudakov effects No-BK evolution Geometric scaling
12
![Page 13: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/13.jpg)
Mapping the phase structure
RHIC
04/19/23 13
CSS
1GeV
pA at LHC
![Page 14: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/14.jpg)
Universality of UGD
Un-ambiguously study at the EIC
04/19/23 14
![Page 15: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/15.jpg)
Conclusion
Sudakov double logs are re-summed in the small-x saturation formalism
Hard processes are used to map the phase structure of cold nuclei at small-x
Further developments shall follow to fully investigate the QCD dynamics at small-x in dense medium
04/19/23 15
![Page 16: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/16.jpg)
PHENIX JdA
16
![Page 17: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/17.jpg)
EIC predictions
17
![Page 18: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/18.jpg)
pA at the LHC
18
PT
![Page 19: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/19.jpg)
Violation effects
04/19/23 19
xG(2)
xG(1)
xG(1)Fqgqg
![Page 20: Mapping the Phase Structure of Cold Nuclei -- Gluon Saturation at small-x](https://reader030.fdocuments.net/reader030/viewer/2022032606/56812ca0550346895d914777/html5/thumbnails/20.jpg)
Compare to the STAR data
η1~η2~3.1 GBW model for UGDs Qs
2~(3.10-4/x)0.28GeV2
Q2sA~0.45A(1/3) Qsp
2
No Sudakov effects No-BK evolution Geometric scaling
20