TAU – “B-PHYSICS” @ LHC

ISRAEL FRANCE INTRODUCTION MEETING

EREZ ETZIONTEL AVIV UNIVERSITY

21.2.2011

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• The Team1

• j/ψ @ PP2

• Search for heavy Z3

• Dimuon @ HI4

Brief Overview

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The TAU – (mu)Team

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TAU -> MUON Team

• Staff (4/7):– G. Bella, A. Soffer, EE, (H. Abramowicz, G. Alexander)

• Technical staff:– Yan Benhammou, Meny Ben Moshe

• Students (7/9):– Nir Amram– Noam Hod– Yonathan Munwes– Yiftah Silver– Avi Gershon– Nimrod Taiblum– Adi Ashkenazi

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Major Activities

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• Hardware:• TGC tests @ TAU, and @ CERN, installation..• TGC for sLHC• MDT gas calibration chambers• PPS

• Software• CSC, MDT tracking• EF trigger• DB• Alignment• DQ

• Analysis

621/02/2011

Schematic view of one layer of TGC

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j/ψ @ PP(NA, YM, GB, EE)

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821/02/2011

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Event/candidate selection

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2.27 pb-1

s = 46 MeV s = 111 MeV

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prompt vs indirect

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Discriminating variable: pseudo-proper time

Variables calculated on a candidate-by-candidate basis

Mass and lifetime distributions fitted simultaneously

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Non prompt fraction

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• Present experimental knowledge is incomplete and contradictory

• CDF measured a slightly longitudinal polarization of the inclusive prompt cross-section is incompatible with Color Singlet Model as well as NRQCD – COM.

• More recently, calculations of (NLO) QCD corrections to color-singlet quarkonium production showed an important increase of the high-pT rate, significantly decreasing the color-octet component needed to reproduce the quarkonium production cross-sections measured at the Tevatron

• Disagreement between CDF results for the J/ψ obtained from RunI and RunII

• Contradictory results obtained by CDF and D0 for the ϒ(1S)

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Next step - Polarization

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• We want to measure the polarization of directly produced J/ψs• The polarization measured using the angular distribution of the daughter

particles

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Angular distribution

θ* is the angle between the direction of the positive muon in the decay frame with respect to the direction of the J/ψ in the laboratory frame

Φ* is the angle between the J/ψ production plane and the J/ψ decay plane

****2*2 cos2sin2cossincos13/1

1****

*

ddN

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Search for heavy Z like

Gauge boson(NH, YS, AG,

GB, EE)

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1521/02/2011

4 D

time

X,Y,Z

spac

e

Extr

a di

men

sion

s

p

p m+

m-

Z*

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* * *

2 2 2 2 2 2

1 1( )

( ) ( ) ( ) ( )az z z z z z

bA Bs s M M s M M

' '0 , ,pp Z Z

0 0 0

2

22 2 2 2 2 2 22 2 2,

n n n n n n

a b a b a bl f l f l f l f

a b nz z z z z z

g g g g g g QQs

ss M i M s M i M s M i M

As the width of the Z’ and gamma’ is large the approximate function

contain 1 term for both (250GeV vs a mass difference of 1 GeV)

Cross section:

Approximation cross section:

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Inv Mass dist.

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AFB motivation

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Dimuons @ Heavy Ions

(EE)

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2021/02/2011

j/ψ suppressionYeild - Ncorr(J/ψ → μ+μ−)c = Nmeas(J/ψ → μ+μ−)c / ε(J/ψ)c · Widthc

Relative yield - Rc = Ncorrc/Ncorr

40-80

Normalized yield Rcp=Rc/Rcoll (ratio of mean number of binary collisionsNcoll Glauber MC package, systematics –WS parameterization.

2121/02/2011

First Z’s in HIPT>20 |eta|<2.5, 66<signal<116 GeV.BG estimate <2% (not corrected) -> 38 candidates.

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NEAR FUTURE ACTIVITIES

21/02/2011

• Hardware:• TGC for sLHC• PPS

• Software• Alignment• DQ

• Analysis• j/ψ cross section j/ψ polarization• Z* search• j/ψ in HI • Z, W production, PDF (GBL talk + AA)• LL (AS + NT)