DETAILED ANALYSIS OF JETS IN P-P AND PB-PB

COLLISIONS AT ALICE EXPERIMENT - JETALICE

COLLABORATIONCuriosity – Expertise – Collaboration – Challenge - Discovery

Programme : RO-CERNCapacities - Module 3 CERN

Project type : Romania’s participation at CERN

Project leader : Dr. Daniel Felea

October 22, 2013

ISS @ ALICE Offline

Mihaela Gheata– Participates in the CWG9 for QA and DQM, for Run3 software upgrade in the future ALICE O2 facilityand operates the central QA and AOD filtering trains.– She is involved in the data preservation activities in ALICE, contributing to the open access policy, to be approved by the CB.

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Mihai Niculescu– Is responsible for the development and maintenance of the ALICE Offline Event Display and for the visualization framework in general.– He has been adding new functionality and features, as required by the evolution of the ALICE detector and offline reconstruction code for RUN2.

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A rho event in Alieve (ALICE event display) –

AliRoot version 5-02-13-AN. LHC10h run 138730 pass 2 data,

10000138730001.20/AliESDs.root event 6

ISS @ ALICE PWG JE : JETS

Main Objective:To study the leading jets structure (traces of leading parton in event) and the underlying event (remnants of secondary interactions) in order to establish the basic energy distribution in hard collisions .

Secondary Objectives (per year):

2012: to study and characterize proton-proton collisions at 0.9 TeV.

2014: to study and characterize Pb-Pb collisions at 2.76 TeV and compare results with p-p reference data.

JETALICE – JETS6

JETALICE – JETS7

Slide from Rosi Reed’s presentation : “Jet Measurements in ALICE”, at “Jet quenching: the interface between theory and experiment” workshop, CERN, 11-14 February 2013

ISS@ALICE.LHC.CERN.CH � Adrian Sevcenco, Andrea Danu, Daniel Felea, Ciprian Mihai Mitu,

and Catalin Ristea have been studying the leading jets, with

kinematical cuts: 5 – 30 GeV in pT , for the proton-proton data

analysis.

� We will study the distribution of the main partonic energy through

hadronisation (i.e., the study of the transverse momentum

distributions and multiplicity in 20%, 40%, 60%, 80% from N and pT).

� Andrea Danu has produced a draft article with a comparative

analysis on the applicability of the Blast-Wave model for the ALICE

and BRAHMS experiments.

� Andrea Danu, Ion Sorin Zgura, Catalin Ristea, Adrian Sevcenco, and

Ciprian Mihai Mitu have submitted an article to the Romanian

Journal of Physics : “Comparisons among the hadron production in

ultra-relativistic heavy ion collisions in different transverse

momentum ranges. Preliminary results”

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ISS @ ALICEDistribution of highest energetic particles;

FastJet 3.x – AntiKT algorithm (0.4 radius)

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Interesting behavior

Interesting behavior

Analysis problem ?

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ISS @ ALICEDistribution of highest energetic particles;

FastJet 3.x – AntiKT algorithm (0.4 radius)

Jet core + UE effects?

Neutral tracks contribution ~ √s ?

“Full jets” definition problem?

ISS @ ALICE

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� Identification of redundant and inefficient use of cmake

include directives ;

� Identification of RangeDefinition usage and replacement

with Selector ;

� JetMedianBackgroundEstimator :: quantify the difference

in ρ determination and provide an easy method for legacy

usage ;

� JetMedianBackgroundEstimator :: σ calculation fixed.

Quantify the difference and provide a legacy method.

� GhostedAreaSpec :: bias in ρ estimates fixed; (different

ghosts placing). Quantify the difference and provide a

legacy method.

Validation of FastJet 3.x version for usage by ALICE

ISS @ ALICE12

Perspectives for 2014 (and 2015)

CERN collaboration

Figure from “Method for separating jets and the underlying

event in heavy ion collisions at the BNL Relativistic Heavy Ion”,

(J.A. Hanks et al.) Phys. Rev. C 86, (2012) 024908

Modified figure from the Gavin Salam’s presentation : “Thoughts on jet reconstruction in heavy-ion collisions”, at

“Jet quenching: the interface between theory and experiment” workshop, CERN, 11-14 February 2013

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ISS @ ALICEPerspectives for 2014 (and 2015)

CERN collaboration

Correlation function C(R) vs. distance between particles (R) in Leading Jet, in p-p at 2.76 GeV Pythia event : Dc = 2.5 0.1

Ongoing p-p, p-Pb, and Pb-Pb Monte Carlo simulations and data analysis at LHC energies

ISS @ ALICE

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� 14 ALICE papers published (B. Abelev, …, A. Danu, D. Felea, A.

Gheata, M. Gheata, M. Haiduc, C.M. Mitu, A. Sevcenco, I. Stan, I.S. Zgura et al.)

� 1 Oral presentation at the ACAT 2013, Beijing (M. Gheata)

� 1 Oral presentation at the CHEP 2013 (M. Niculescu)

� 1 Participation at GridKa School 2013 – at the Karlsruhe Institute of Technology, Germany (A. Sevcenco)

Result capitalization

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ISS @ ALICE Outreach

The Romanian researchers study the beginning of the Universe.

The novel experiment from Geneva

Interview by Andrada Fiscutean (April 8, 2013) –Andrea Danu participated for the ISS-ALICE group

Yoda.ro (PRO TV)

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ISS @ ALICE Outreach

During “The Researchers’ Night”,Andrea Danu participated for the ISS-ALICE group, on the 27th of September

2013, with a presentation of CERN and ALICE experiment : “CERN in images”

During “Otherwise School” Campaign, initiated by

the Ministry of National Education,Andrea Danu, Adrian Sevcenco, Ciprian Mihai Mitu

and Ionel Stan participated (April 1-5, 2013) at the outreach activities at the Institute of Space Science

400 CPU ( 550 kSI2K) - 640 GB memory - 210 TB storage space

10 GigE upstream connection to DANTE network through RoEduNet

ISS @ ALICE GRID Computing

� Second place in GRID Romanian Federation (18%)

� Close collaboration with WLCG Romanian partners (CONDEGRID)

� High utilization by ALICE user analyses (1%)

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ISS @ ALICEHigh computing

contribution/cost ratio

Thank you !

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