Inclusive prompt photon-jet correlations as a probe of gluon saturation in electron-nucleus scattering at small $x$

Kolbé, Isobel; Roy, Kaushik; Salazar, Farid; Schenke, Bjoern; Venugopalan, Raju

doi:10.1007/JHEP01(2021)052

Inclusive prompt photon-jet correlations as a probe of gluon saturation in electron-nucleus scattering at small $x$

Isobel Kolbé
(
- Washington U., Seattle and
- iThemba LABS
)
,
Kaushik Roy
(
- Brookhaven and
- SUNY, Stony Brook
)
,
Farid Salazar
(
- Brookhaven and
- SUNY, Stony Brook
)
,
Bjoern Schenke
(
- Brookhaven
)
,
Raju Venugopalan
(
- Brookhaven
)

Aug 10, 2020

61 pages

Published in:

JHEP 01 (2021) 052

Published: Jan 12, 2021

e-Print:

2008.04372 [hep-ph]

DOI:

10.1007/JHEP01(2021)052 (publication)

View in:

ADS Abstract Service

reference search32 citations

Citations per year

Abstract: (Springer)

We compute the differential cross-section for inclusive prompt photon+quark production in deeply inelastic scattering of electrons off nuclei at small x (e + A DIS) in the framework of the Color Glass Condensate effective field theory. The result is expressed as a convolution of the leading order (in the strong coupling α

_{s}

) impact factor for the process and universal dipole matrix elements, in the limit of hard photon transverse momentum relative to the nuclear saturation scale Q

_{s,A}

(x). We perform a numerical study of this process for the kinematics of the Electron-Ion Collider (EIC), exploring in particular the azimuthal angle correlations between the final state photon and quark. We observe a systematic suppression and broadening pattern of the back-to-back peak in the relative azimuthal angle distribution, as the saturation scale is increased by replacing proton targets with gold nuclei. Our results suggest that photon+jet final states in inclusive e + A DIS at high energies are in general a promising channel for exploring gluon saturation that is complementary to inclusive and diffractive dijet production. They also provide a sensitive empirical test of the universality of dipole matrix elements when compared to identical measurements in proton-nucleus collisions. However because photon+jet correlations at small x in EIC kinematics require jet reconstruction at small k

_{⊥}

, it will be important to study their feasibility relative to photon-hadron correlations.

Note:

41 pages, 7 figures

Deep Inelastic Scattering (Phenomenology)
QCD Phenomenology
photon: production
gluon: saturation
scale: saturation
photon: transverse momentum
jet: correlation
jet: final state
electron nucleus: deep inelastic scattering
track data analysis: jet

References(103)

Figures(10)

[1]

Semihard Processes in QCD

- Phys.Rept. 100 (1983) 1-150,
- Phys. Rep. 100 ( 1983) 1-150
•
DOI:
- 10.1016/0370-1573(83)90022-4

[2]

Gluon Recombination and Shadowing at Small Values of x

Alfred H. Mueller
(
- Columbia U.
)
,
Jian-wei Qiu
(
- Columbia U.
)

- Nucl.Phys.B 268 (1986) 427-452
•
DOI:
- 10.1016/0550-3213(86)90164-1

[3]

Electron Ion Collider: The Next QCD Frontier : Understanding the glue that binds us all

A. Accardi
(
- Jefferson Lab and
- Hampton U.
)
,
J.L. Albacete
(
- Orsay, IPN
)
,
M. Anselmino
(
- INFN, Turin and
- Turin U.
)
,
N. Armesto
(
- Santiago de Compostela U.
)
,
E.C. Aschenauer
(
- Brookhaven
)

et al.

- Eur.Phys.J.A 52 (2016) 9, 268
•
e-Print:
- 1212.1701
•
DOI:
- 10.1140/epja/i2016-16268-9

The electron–ion collider: assessing the energy dependence of key measurements

et al.

- Rept.Prog.Phys. 82 (2019) 2, 024301
•
e-Print:
- 1708.01527
•
DOI:
- 10.1088/1361-6633/aaf216

Measurement of isolated photons accompanied by jets in deep inelastic $ep$ scattering

ZEUS

Collaboration

•

H. Abramowicz
(
- Tel Aviv U.
)

et al.

- Phys.Lett.B 715 (2012) 88-97
•
e-Print:
- 1206.2270
•
DOI:
- 10.1016/j.physletb.2012.07.031

Isolated photons in deep inelastic scattering

A. Gehrmann-De Ridder
(
- Zurich, ETH
)
,
T. Gehrmann
(
- Zurich U.
)
,
E. Poulsen
(
- Zurich U.
)

- Phys.Rev.Lett. 96 (2006) 132002
•
e-Print:
- hep-ph/0601073
•
DOI:
- 10.1103/PhysRevLett.96.132002

Measuring the Photon Fragmentation Function at HERA

A. Gehrmann-De Ridder
(
- Zurich, ETH
)
,
T. Gehrmann
(
- Zurich U.
)
,
E. Poulsen
(
- Zurich U.
)

- Eur.Phys.J.C 47 (2006) 395-411
•
e-Print:
- hep-ph/0604030
•
DOI:
- 10.1140/epjc/s2006-02574-x

Photon plus jet-cross sections in deep inelastic e p collisions at order O(alpha**2 alpha(s))

A. Gehrmann-De Ridder
(
- Karlsruhe U.
)
,
G. Kramer
(
- Hamburg U.
)
,
H. Spiesberger
(
- Mainz U., Inst. Phys.
)

- Nucl.Phys.B 578 (2000) 326-350
•
e-Print:
- hep-ph/0003082
•
DOI:
- 10.1016/S0550-3213(00)00228-5

[9]

Photon-Jet cross sections in Deep-Inelastic Scattering

P. Aurenche
(
- Annecy, LAPTH
)
,
M. Fontannaz
(
- Orsay, LPT
)

- Eur.Phys.J.C 75 (2015) 2, 64
•
e-Print:
- 1411.4878
•
DOI:
- 10.1140/epjc/s10052-015-3296-x

[10]

Photon–jet correlations in deep-inelastic scattering

P. Aurenche
(
- Annecy, LAPTH
)
,
M. Fontannaz
(
- Orsay, LPT
)

- Eur.Phys.J.C 77 (2017) 5, 324
•
e-Print:
- 1704.08074
•
DOI:
- 10.1140/epjc/s10052-017-4910-x

Computing quark and gluon distribution functions for very large nuclei

Larry D. McLerran
(
- Minnesota U.
)
,
Raju Venugopalan
(
- Minnesota U.
)

- Phys.Rev.D 49 (1994) 2233-2241
•
e-Print:
- hep-ph/9309289
•
DOI:
- 10.1103/PhysRevD.49.2233

Gluon distribution functions for very large nuclei at small transverse momentum

Larry D. McLerran
(
- Minnesota U.
)
,
Raju Venugopalan
(
- Minnesota U.
)

- Phys.Rev.D 49 (1994) 3352-3355
•
e-Print:
- hep-ph/9311205
•
DOI:
- 10.1103/PhysRevD.49.3352

Green's functions in the color field of a large nucleus

Larry D. McLerran
(
- Minnesota U.
)
,
Raju Venugopalan
(
- Minnesota U.
)

- Phys.Rev.D 50 (1994) 2225-2233,
- Phys. Rev. D50 (1994) 2225-2233, and Minnesota Univ. Minneapolis - TPI-MINN-94-07-T (94/02,rec.Feb.) 21 p. (407292) Minnesota Univ. Minneapolis - NUC-MINN-94-02-T (94/02,rec.Feb.) 21 p
•
e-Print:
- hep-ph/9402335
•
DOI:
- 10.1103/PhysRevD.50.2225