Transverse momentum vs. multiplicity correlations

Agnieszka Wojtaszek-SzwarcJan Kochanowski University

NA61/SHINE and NA49 meeting in Warsaw 10-14.02.2014

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Analysis of pT - <N> correlation

• Pb+Pb collision at 158, 80, 40, 30 and 20A GeV• Only forward rapidity tracks 1.1< yCMS < 2.6,

(rapidity is calculated assuming pion mass for all particles) with 0.005< pT <1.5 GeV/c have been used in this analysis.

• Analysis have been done in narrow centrality bins

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Example of pT - N correlations

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Pb+Pb at 160A GeV

Centrality 3.5% – 4.0%

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b parameter vs. centrality – all charged particles

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b parameter vs. centrality – negatively charged particles

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b parameter vs. centrality – positively charged particles

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VENUS dataPb + Pb 158A GeV

4 centrality bins – 25 k events in each bin

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<pT> vs. N , negatively charged particles. MC data Pb+Pb at 158A GeV. Collision parameter 1 fm < b <1.5 fm. 0.005 < pT < 1.5 4.0 < y < 5.5

VENUS + acceptaneb = 3.21 1.0

VENUS + reconstruction + acceptanceb = 3.81 1.1

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VENUS – top panelsVENUS + acceptance – bottom panels

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VENUS + reconstruction – top panelsVENUS + reconstruction + acceptance – bottom panels

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Negatively charged particles, centrality 1.0-1.5

Venus + reconstructionVenus

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<pT> vs. N , negatively charged particles. MC data Pb+Pb at 158A GeV. Collision parameter 5 fm < b <5.5 fm. 0.005 < pT < 1.5 4.0 < y < 5.5

VENUS + acceptaneb = 3.21 1.0

VENUS + reconstruction + acceptanceb = 3.81 1.1

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<pT> vs. N , negatively charged particles. MC data Pb+Pb at 158A GeV. Collision parameter 9 fm < b <9.5 fm. 0.005 < pT < 1.5 4.0 < y < 5.5

VENUS + acceptaneb = 0.06 0.91

VENUS + reconstruction + acceptanceb = 0.03 0.9

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<pT> vs. N , negatively charged particles. MC data Pb+Pb at 158A GeV. Collision parameter 12 fm < b <12.5 fm. 0.005 < pT < 1.5 4.0 < y < 5.5

VENUS + acceptaneb = -2.32 0.8

VENUS + reconstruction + acceptanceb = -5.06 1.0

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Data std +

Collision parameter

Negatively charged

Positively charged

All charged

b b b b b b

VENUS + ACC 1.0 – 1.5 5.53 1.19 5.73 1.19 6.08 1.09

VENUS + REC + ACC 7.12 1.24 8.35 1.45 11.82 1.25

VENUS + ACC 5.0 – 5.5 3.21 1.0 2.50 1.08 2.57 0.92

VENUS + REC + ACC 3.81 1.1 3.21 1.3 3.71 1.04

VENUS + ACC 9.0 – 9.5 -0.06 0.91 0.9 0.96 -1.89 0.78

VENUS + REC + ACC 0.03 0.9 -1.39 1.16 -2.35 0.9

VENUS + ACC 12.0 – 12.5 -2.32 0.80 0.26 0.86 -2.09 0.67

VENUS + REC + ACC -2.47 0.83 -5.06 1.00 -5.06 0.74

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VENUS dataPb + Pb 80A GeV

2 centrality bins – 25 k events in each bin

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<pT> vs. N , negatively charged particles. MC data Pb+Pb at 80A GeV. Collision parameter 1 < b <1.5 0.005 < pT < 1.5 4.0 < y < 5.5

VENUS + acceptaneb = 3.54 1.14

VENUS + reconstruction + acceptanceb = 1.59 0.81

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Negatively charged particles, centrality 1.0-1.5

Venus + reconstructionVenus

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VENUS – top panelsVENUS + acceptance – bottom panels

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VENUS + reconstruction – top panelsVENUS + reconstruction + acceptance – bottom panels

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<pT> vs. N , negatively charged particles. MC data Pb+Pb at 80A GeV. Collision parameter 5 fm < b < 5.5 fm 0.005 < pT < 1.5 4.0 < y < 5.5

VENUS + acceptaneb = 2.77 1.10

VENUS + reconstruction + acceptanceb = 1.03 0.79

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Data std +

Collision parameter

Negatively charged

Positively charged

All charged

b b b b b b

VENUS + ACC 1.0 – 1.5 3.54 1.14 1.96 1.16 2.36 1.11

VENUS + REC + ACC 1.59 0.81 3.35 1.11 3.23 1.00

VENUS + ACC 5.0 – 5.5 2.77 1.1 4.12 1.13 4.07 1.07

VENUS + REC + ACC 1.03 0.79 2.61 1.05 1.37 0.94

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Correction of influence of detector acceptance on final results • For one collision energy we need 20 centrality bins. • 25 000 events in each bin.• Estimated time – 10 – 20 weeks for simulations of one collision energy (simulated data are stored on the tapes and reading them is time consuming process).• For preparation full statistic for all 5 collision energies we need 2 years.

Differences of value b for collision energy 158 and 80A GeV are smaller then statistical uncertainty of experimental data.

Good solution is to check the influence of detector acceptance for 3 different centrality bins for each collision energy. If the influence is too small we should publish data without any correction.

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Additional slides

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Additional slides

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Additional slides

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Additional slides

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Additional slides