Prof.
Konstantin Goulianos
(The Rockefeller University)

4/28/15, 8:30 AM

WG2 Small-x, Diffraction and Vector Mesons

Predictions of diffractive, total, and total-inelastic cross sections at the LHC, based on the pre-LHC renormalization model of diffraction RENORM, are reviewed and compared with the latest experimental results. RENORM is found to be in reasonable agreement with all aspects of the data and is extended to include predictions for the upcoming LHC run at 13 TeV.

Grzegorz Brona
(University of Warsaw (PL))

4/28/15, 8:55 AM

WG2 Small-x, Diffraction and Vector Mesons

The differential diffractive cross section is measured as a function of xi= M_X^2/s in the region dominated by single dissociation (SD) and double dissociation (DD), where M_X is the mass of one of the two final-state hadronic systems separated by the largest rapidity gap in the event. The cross section is also measured as a function of the width of the central rapidity gap in the region...

Dr
Mario Deile
(CERN)

4/28/15, 9:20 AM

WG2 Small-x, Diffraction and Vector Mesons

We present the final results on low-$|t|$ elastic proton-proton scattering at $\sqrt{s} = 8$ TeV based on two data sets acquired with different, dedicated beam-optics settings. A very high statistics sample allowed, for the first time at LHC energies, the exclusion of a purely exponential differential cross-section in the four-momentum range $0.027 < |t| < 0.2~\rm GeV^2$ with a significance...

Leszek Adamczyk
(AGH University of Science and Technology (PL)),
Leszek Adamczyk
(AGH University of Science and Technology (PL))

4/28/15, 9:45 AM

WG2 Small-x, Diffraction and Vector Mesons

The total pp cross section is a fundamental parameter of the strong interaction which cannot be calculated in QCD but still can be measured using the optical theorem, which states that the total cross section can be obtained from the extrapolation to t=0 of the differential elastic cross section measured at small four-momentum transfer t.
The ATLAS Collaboration has collected 80 mub-1 of...

Michael Albrow
(Fermi National Accelerator Lab. (US))

4/28/15, 10:45 AM

WG2 Small-x, Diffraction and Vector Mesons

The CMS-TOTEM Precision Proton Spectrometer, CT-PPS, is an approved project to add
3D silicon tracking and quartz Cherenkov timing detectors in Roman pots at z = +/- 210 m
from the CMS collision point to study final states p + X + p. The central state X can be a W-pair from photon-photon interactions, a set of high-ET jets from gluon collisions, among others, with M(X) obtained directly as...

Alex Kovner
(UConn)

4/28/15, 11:10 AM

WG2 Small-x, Diffraction and Vector Mesons

We reconsider the perturbative next-to-leading calculation of the single inclusive hadron production in the framework of the hybrid formalism, applied to hadron production in proton-nucleus collisions. We introduce the explicit requirement that fast fluctuations in the projectile wave function which only exist for a short time are not resolved by the target. This Ioffe time cutoff also...

Piotr Kotko

4/28/15, 11:35 AM

WG2 Small-x, Diffraction and Vector Mesons

We study forward dijet production in dilute-dense hadronic collisions. By considering the appropriate limits, we show that both the transverse-momentum-dependent (TMD) and the high-energy factorization formulas can be derived from the Color Glass Condensate framework. Respectively, this happens when the transverse momentum imbalance of the dijet system, $k_t$, is of the order of either the...

Adrian Dumitru
(Baruch College (City University of New York))

4/28/15, 12:00 PM

WG2 Small-x, Diffraction and Vector Mesons

Experiments at RHIC and the LHC have revealed anisotropic
multi-particle azimuthal correlations in high multiplicity pp and pA
collisions. These correlations are long range in rapidity (resp. log 1/x) and extend to semi-hard transverse momenta of several GeV. I discuss first steps towards understanding azimuthal correlations from
small-x QCD, and the information they could provide about...

Prof.
Chung-I Tan
(Brown University)

4/28/15, 2:00 PM

WG2 Small-x, Diffraction and Vector Mesons

We focus on a holographic approach to DIS at small-x in high energy where scattering is dominated by exchanging a Reggeized Graviton in $AdS_5$. We emphasize the importance of confinement, which corresponds to a deformation of $AdS_5$ geometry in the IR. This approach provides
an excellent fit to the combined HERA data at small $x$. We also discuss the constraints of unitarity and...

Dr
Stefan Schmitt
(Deutsches Elektronen-Synchrotron (DE))

4/28/15, 2:25 PM

WG2 Small-x, Diffraction and Vector Mesons

A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic ep scattering at HERA using data collected by the H1 experiment corresponding to an integrated luminosity of 290 pb^{-1}. The investigated phase space is spanned by the photon virtuality in the range of 4< Q^{2} <100 GeV^{2} and by the fractional proton longitudinal momentum loss...

Dr
Stefan Schmitt
(Deutsches Elektronen-Synchrotron (DE))

4/28/15, 2:50 PM

WG2 Small-x, Diffraction and Vector Mesons

The cross section of the diffractive process e^+p -> e^+Xp is measured at a centre-of-mass energy of 318 GeV, where the system X contains at least two jets and the leading final state proton p is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction with photon virtualities Q^2 <2 GeV^2 and in deep-inelastic scattering with 4 GeV^2< Q^2 <80 GeV^2....

Leszek Adamczyk
(Cracow AGH-UST),
Leszek Adamczyk
(AGH University of Science and Technology (PL))

4/28/15, 3:15 PM

WG2 Small-x, Diffraction and Vector Mesons

The exclusive dijet production in diffractive deep inelastic $e^\pm p$ scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 372 pb$^{−1}$. The measurement was performed for $\gamma^*-p$ centre-of-mass energies in the range $90 < W < 250$ GeV and photon virtualities in the range $Q^2$ > 25 GeV$^2$ . Energy and transverse-energy flows around the jet axis...

Michal Praszalowicz
(Jagellonian University, Krakow)

4/28/15, 4:15 PM

WG2 Small-x, Diffraction and Vector Mesons

Gluon distrubutions of colliding hadrons saturate
as a consequence of non-linear evolution equations of QCD.
Saturation implies the existence of the so called
saturation momentum, which is related to the gluon density
per unit rapidity per transverse area. At large energies
in some regions of phase space the saturation momentum
is the only scale for physical processes. As a...

Martin Hentschinski
(Institute for Nuclear Science, UNAM)

4/28/15, 4:40 PM

WG2 Small-x, Diffraction and Vector Mesons

We present the results for the calculation of the forward jet vertex associated to a rapidity gap (coupling of a hard pomeron to the jet) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism at next-to-leading order (NLO). We handle the real emission contributions making use of the high energy effective action proposed by Lipatov, valid for multi-Regge and quasi-multi-Regge kinematics. This...

Amir Rezaeian
(Universidad Tecnica Federico Santa Maria)

4/28/15, 5:05 PM

WG2 Small-x, Diffraction and Vector Mesons

I will discuss that diffractive production at small-x, including diffractive photo production of vector mesons and dijet can be a powerful probe of non-linear gluon-saturation dynamics [1,2]. In particular, I will focus on the diffractive dijet production at HERA and the LHC within the color-glass-condensate approach [2]. I will show that the t-distribution of photoproduction of dijet and...

Prof.
Kirill Tuchin
(Iowa State University)

4/28/15, 5:30 PM

WG2 Small-x, Diffraction and Vector Mesons

I calculate the Coulomb corrections to the total and diffractive cross sections
in DIS off heavy nuclei. I show that they violate the geometric
scaling and have important phenomenological implications for a future EIC program.

Joakim Nystrand
(University of Bergen (NO))

4/29/15, 8:30 AM

WG2 Small-x, Diffraction and Vector Mesons

Particle production through photon-induced processes in
ultra-peripheral collisions has attracted an increasing interest
following the first heavy-ion runs at the CERN Large Haron Collider.
The increased collision energy compared with the Relativistic
Heavy-Ion Collider (RHIC) at BNL implies that also heavy final states
can be produced in abundance. The focus has so far been on...

Maria Beatriz Gay Ducati
(UFRGS)

4/29/15, 8:55 AM

WG2 Small-x, Diffraction and Vector Mesons

Recent results for the coherent photoproduction of vector mesons psi(1S),
psi(2S) and Upsilon (1S) in the hadron-hadron and nucleus-nucleus collisions in the LHC energies are presented. Predictions for the rapidity distributions are obtained using the color dipole formalism and including saturation effects, expected to be relevant at high energies. Comparison is done to the J/psi and Psi(2S)...

Michael Murray
(University of Kansas (US))

4/29/15, 9:20 AM

WG2 Small-x, Diffraction and Vector Mesons

The nature of the initial state can be studied in photon-nucleus collisions at the LHC. Ultra-peripheral collisions (UPCs) of heavy ions involve long range electromagnetic interactions at impact parameters larger than twice the nuclear radius. At TeV energies, the strong electromagnetic field due to the coherent action of the Z=82 proton charges generates a large flux of photons, which can be...

Jaroslav Adam
(Czech Technical University (CZ))

4/29/15, 9:45 AM

WG2 Small-x, Diffraction and Vector Mesons

Ultra-relativistic heavy ions generate strong electromagnetic fields, which
offer the possibility to study gamma-gamma, gamma-nucleus and gamma-proton
processes at the LHC in ultra-peripheral Pb-Pb and p-Pb collisions (UPC).
Exclusive photoproduction of vector mesons is sensitive to
the gluon distribution of the interacting target (proton or nucleus).
The reactions allow one to study...

Prof.
Thomas Ullrich
(BNL)

4/29/15, 10:45 AM

WG2 Small-x, Diffraction and Vector Mesons

The demand for detailed simulations of diffractive processes at an electron-ion collider (EIC) required the realization of an event generator that described these processes not only in ep but especially also in eA. Since gluon saturation is one of the key topics in eA collisions at an EIC, the generator was also required to be able to describe these non-linear QCD phenomena but also be able...

Nataliia Kovalchuk
(Hamburg University (DE))

4/29/15, 11:10 AM

WG2 Small-x, Diffraction and Vector Mesons

The exclusive deep inelastic electroproduction of $\psi(2S)$ and $J/\psi$ has been studied with the ZEUS detector at HERA in the kinematic range $2 \le Q^2 \le 80$ GeV$^2$, $30 \le W \le 210$ GeV and $|t| \le 1$ GeV$^2$, where $Q^2$ is the photon virtuality, $W$ is the photon-proton centre-of-mass energy and $t$ is the squared four-momentum transfer at the proton vertex. The data for $2 \le...

Ronan James Wallace
(University College Dublin (IE))

4/29/15, 11:35 AM

WG2 Small-x, Diffraction and Vector Mesons

The recent LHCb results on central exclusive production are presented.

Dr
Michael Albrow
(Fermi National Accelerator Laboratory)

4/29/15, 12:00 PM

WG2 Small-x, Diffraction and Vector Mesons

We measure exclusive pi+pi- production in proton-antiproton collisions at center-of-mass energies sort(s) = 0.9 and 1.96 TeV in the Collider Detector at Fermilab. We select events with two oppositely charged particles, assumed to be pions, with pseudorapidity
|eta| < 1.3 and with no other particles detected in |eta| < 5.9. We require the pi+pi- system to have rapidity |y| < 1.0. The...

Michael Lublinsky

4/29/15, 2:00 PM

WG2 Small-x, Diffraction and Vector Mesons

We present a construction of an effective high energy QCD Hamiltonian at NLO accuracy. This Hamiltonian is an NLO extension of the JIMWLK LO Hamiltonian, known to incorporate BFKL dynamics with gluon saturation phenomena. We are to demonstrate how the conformal symmetry is realized within the NLO JIMWLK.

Andrey Grabovskiy
(Budker Institute of Nuclear Physics (RU))

4/29/15, 2:25 PM

WG2 Small-x, Diffraction and Vector Mesons

The next to leading order low x evolution equation for the next after the dipole operator will be discussed.

Dr
Giovanni Chirilli

4/29/15, 2:50 PM

Madrigal Martínez José Daniel
(IPhT CEA Saclay)

4/29/15, 4:15 PM

WG2 Small-x, Diffraction and Vector Mesons

Starting at NLO, the BFKL-BK evolution in high-energy QCD develops severe convergence problems. The most important source for this behavior can be traced down to large double collinear logarithms. We show via explicit computation of Feynman diagrams that corrections enhanced by double logs correspond to soft gluon emissions strongly ordered in lifetime, while other potential contributions...

Andrey Tarasov
(Jefferson Lab)

4/29/15, 4:40 PM

WG2 Small-x, Diffraction and Vector Mesons

A TMD factorization generalizes the usual concept of parton density by allowing PDFs to depend on intrinsic transverse momenta in addition to the usual longitudinal momentum fraction variable. The available analysis of TMD evolution is mostly restricted to the evolution of quark TMDs at moderate x. However at high collider energies the majority of produced particles will be small-x gluons. In...

Dr
Peter Bussey
(University of Glasgow)

4/29/15, 5:05 PM

WG2 Small-x, Diffraction and Vector Mesons

Using data from HERA, the ZEUS collaboration present measurements of the diffractive production of isolated ("prompt") photons in photoproduction, with and without a jet. First cross sections are evaluated for centrally produced photons with jets as a function of the photon and jet transverse energy and pseudorapidity, and also for the fraction of incoming photon energy imparted to the...

Anna Stasto
(Penn State)

4/30/15, 8:30 AM

WG2 Small-x, Diffraction and Vector Mesons

We construct a theoretical framework to match the formulas for forward inclusive hadron productions in pA collisions in the small-x saturation formalism and collinear factorization. The small-x calculation can be viewed as a power series in Q2s/k2⊥, in which the collinear factorization result corresponds to the leading term. At high transverse momentum, the subleading correction terms are...

Tolga Altinoluk
(Universidade de Santiago de Compostela)

4/30/15, 8:55 AM

WG2 Small-x, Diffraction and Vector Mesons

We present a new method to systematically calculate corrections to the eikonal approximation in the background field formalism. We calculate the subleading power-suppressed corrections due to the finite width of the target to first and second orders. The method is of generic applicability. As a first example, we study both polarized and unpolarized gluon production in pA collisions.

Douglas Wertepny
(The Ohio State University)

4/30/15, 9:20 AM

WG2 Small-x, Diffraction and Vector Mesons

The classical single-gluon production amplitude in nucleus-nucleus collisions
including the first saturation correction in one of the nuclei (the projectile) while keeping multiple-rescattering (saturation) corrections to all orders in the other nucleus (the target) is presented.
We expand one of the two nuclei up to two Wilson lines (i.e only two nucleons interact in the projectile...

Feng Yuan
(LBNL)

4/30/15, 9:45 AM

WG2 Small-x, Diffraction and Vector Mesons

In this talk, we will discuss the theory developments on the next-to-leading order calculation for forward hadron production in pA collisions in the small-x factorization framework. In particular, we emphasize the matching between this calculation and the collinear factorization calculation at large transverse momentum. The small-x calculation can be viewed as a power series in $Q_s^2/k_T^2$,...

Dr
Erez Reinherz-Aronis

4/30/15, 10:45 AM

WG2 Small-x, Diffraction and Vector Mesons

This talk will present recent results on neutrino interaction cross sections from the T2K experiment.

Jonathan Asaadi
(Syracuse University),
Jonathan Asaadi
(urn:Google)

4/30/15, 11:10 AM

WG2 Small-x, Diffraction and Vector Mesons

The analysis and interpretation of the present and future neutrino oscillation experiments
strongly rely on the quantitative understanding of neutrino and antineutrino interactions with nuclei in the "few GeV" energy range. With the advent of the Liquid Argon Time Projec-
tion Chamber (LArTPC) experimental techniques for neutrino detection, a novel approach and
methodology in neutrino data...

Dr
Xinchun Tian
(Univ. of South Carolina)

4/30/15, 11:35 AM

WG2 Small-x, Diffraction and Vector Mesons

New measurements of coherent ρ0 and ρ+ production in NOMAD are reported. We present simulation of neutrino induced coherent ρ-meson production in charged and neutral current interactions. Sensitivity studies of this process for next generation neutrino scattering experiments is presented.