10th International Workshop on Multiple Partonic Interactions at the LHC

Session

WG4

10 Dec 2018, 11:10

Auditorium Santa Cecilia , Perugia, Italy

Description

Antonio Ortiz, Klaus Werner

18. Small system physics from CMS: energy and multiplicity dependence of particle correlations

Arthur Moraes (CBPF - Brazilian Center for Physics Research (BR))

10/12/2018, 11:10

The CMS collaboration presents two talks on small-system physics. This contribution will focus specifically on the dependence of particle correlations on energy and multiplicity

7. Collectivity in small collision systems with ALICE

Katarina Gajdosova (Czech Technical University (CZ))

10/12/2018, 11:40

Measurements of anisotropic flow provide an important insight into the nature of collectively expanding hot and dense strongly coupled matter in heavy-ion collisions. Over the past years, striking similarities were revealed in numerous experimental results measured in high-multiplicity proton-proton and proton-lead interactions, where no emergence of such a medium was expected.

In this talk,...

13. Low-mass dielectron measurements in high-multiplicity pp collisions with ALICE at the LHC

Ivan Vorobyev (Technische Universitaet Muenchen (DE))

10/12/2018, 12:00

Electron-positron pairs produced in ultra-relativistic heavy-ion collisions at the LHC carry important information about the system space-time evolution unperturbed by strong final-state interactions. The dielectron continuum is very rich in physics sources: on top of Dalitz and resonance decays of pseudo-scalar and vector mesons, thermal black-body radiation contains the information about the...

32. Modification of inclusive and heavy-flavor jet structures in high-multiplicity pp collisions

Robert Vertesi (Hungarian Academy of Sciences (HU))

10/12/2018, 12:20

High multiplicity events of small colliding systems at high c.m.s. energies show similar collective features to heavy ion collisions with comparable multiplicities, such as long-range near-side correlations and v_n coefficients [1]. Whether this behaviour may be attributed to the presence of a deconfined state in small systems is an open question. Recent analyses of pp and p-Pb collisions also...

29. Measurements of correlated hadron production with the ATLAS detector

Sarka Todorova (Centre National de la Recherche Scientifique (FR))

10/12/2018, 12:40

Abstract: We present studies shedding light on the correlated hadron production. This is an important source of information about the early stages of hadron formation and is not yet understood from first principles. In this talk, we will present the measurement of Bose-Einstein correlations using the ATLAS detector along with an analysis of the momentum difference between charged hadrons in...

41. Measurements of two-particle correlations in $e^+e^-$ collisions at 91 GeV with ALEPH archived data

Austin Alan Baty (Massachusetts Inst. of Technology (US))

11/12/2018, 09:00

This talk summarize the results on two-particle angular correlations for charged particles emitted in $e^+e^−$ collisions data collected at 91 GeV with the ALEPH detector at LEP. With the archived data, the correlation functions are studied over a broad range of pseudorapidity $\eta$ and azimuthal angle $\phi$ with respect to the electron-positron beam axis and the event thrust axis....

11. Studying minijets and MPI with rapidity correlations

Mark Strikman (Penn State University)

11/12/2018, 09:20

We propose and carry a detailed study of an observable sensitive to different mechanisms of minijet production. The class of observables measures how the transverse momenta of hadrons produced in association with various trigger objects are balanced as a function of rapidity. It is shown that the observables are sensitive to the model parameters relevant for the minijet production mechanisms:...

40. Quarkonium production as a function of charged-particle multiplicity in pp collisions measured by ALICE at the LHC

Ms Tasnuva Chowdhury (Université Clermont Auvergne (FR))

11/12/2018, 09:40

Quarkonium (a bound state of $Q\bar{Q}$ pair) production as a function of charged-particle multiplicity has been measured in pp collisions at the LHC. They exhibit a non-trivial correlation that can lead to a better understanding of the multiple-parton interaction mechanism in the initial state of the collision as well as possible collective effects in small systems. The ALICE detector at the...

47. Energy and multiplicity dependence of identified particle production in small systems with ALICE at the LHC

Stefania Bufalino (Politecnico di Torino (IT))

11/12/2018, 10:00

One of the key results of the LHC Run 1 was the observation of an enhanced production
of strange particles in high multiplicity pp and p-Pb collisions at 7 and 5.02 TeV, respectively.
In addition, the multiplicity dependent results on particle production in pp collisions allowed the discovery of collective-like behavior in small systems at the LHC.
In order to provide further insights into the...

67. Multiplicity dependent J/ψ production in proton-proton collisions with PYTHIA8

Steffen Georg Weber (Technische Universitaet Darmstadt (DE))

11/12/2018, 10:20

The correlation of charmonium (and also of heavy quarks in general) production with the charged particle multiplicity is of high interest, as it could give new insight into the interplay between hard and soft mechanisms in particle production, both at parton level and at hadronization.
Experimental data shows an intriguing increase of the self-normalized J/ψ yield with multiplicity.
In this...

60. Investigating the flow-like correlations with new possibility

You Zhou (University of Copenhagen (DK))

13/12/2018, 17:10

Multiple experimental measurements have shown strong indications of flow in small collision systems. In this talk, I will examine the selected theoretical models with latest as well as well hidden experimental results in small collisions systems. I will discuss which experimental ''evidence" is solid and which might be misinterpreted. In addition, I will show the potential of deep learning in...

43. Effects of geometry initial-state fluctuations on the ridge structure in pp collisions.

Irais Bautista Guzman (Autonomous University of Puebla (MX))

13/12/2018, 17:40

One of the key signatures of collectivity in heavy-ion collisions is the appearance of a ridge structure over wide pseudorapidity interval. Recently it was also found in small collision systems such as proton-proton or proton-ion collisions which origin is still on debate. In this work, contributions from the geometry fluctuations in the initial-state in pp collisions to the ridge structure...

52. Collectivity and MPI

Boris Blok (Physics Department)

13/12/2018, 18:00

We develop a MPI based theory of ridge phenomena in `MPI, the origin of collectivity comes out to be quantum interference of different MPIs. We show that
in this approach we obtain a picture of ridge phenomena in pp collisions compatible both qualitatively and qualitatively with experimental data.
the talk is based on:
Collectivity from interference
Boris Blok (Technion), Christian D. Jäkel...

93. WG4 (High Multiplicity) - Summary

Robert Vertesi (Hungarian Academy of Sciences (HU))

14/12/2018, 09:10

94. Discussion

14/12/2018, 09:20