Impact parameters resolutions in s=13 TeV pp interactions measured - - PowerPoint PPT Presentation

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Aug 10, 2023 311 likes •529 views

Impact parameters resolutions in s=13 TeV pp interactions measured with ATLAS at the LHC Project supervisor: Yuri A. Kulchitsky Student: Zuzana Rekov Project supervisor: Yuri A. Kulchitsky Yuri A. Kulchitsky The

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Impact parameters resolutions in √s=13 TeV pp interactions measured with ATLAS at the LHC

Student: Zuzana Reščáková
Project supervisor: Yuri A. Kulchitsky

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Project supervisor: Yuri A. Kulchitsky

Yuri A. Kulchitsky

The Laboratory of Nuclear problems
Student: Zuzana Reščáková

Zuzana Reščáková

Pavol Jozef Šafárik University in Košice, Slovakia Nuclear and Subnuclear Physics

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ATLAS detector

is a particle physics experiment for pp, pA and AA collisions

investigated for energies 0.9 - 14 TeV at the Large Hadron Collider at CERN

covers almost the whole solid angle around the collision point with

layers of tracking detectors, calorimeters and muon chambers

for our measurements the tracking devices and the trigger system

are of particular importance

ATLAS detector ATLAS trigger detector

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Introduction

Measurements of inclusive charged-particle distributions in

pp collisions at a centre-of-mass energy of 13 TeV provides insights into soft-QCD processes.

The distributions are corrected for detector effects and are

presented as inclusive-inelastic distributions, in a well-defined fiducial region.

These distributions are compared to particle level Monte

Carlo (MC) predictions.

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Motivation

The motivation of these study are analysis of transverse, ,

and longitudinal, , Impact Parameters (IP) distributions within the Inner Detector for Selected, Primaries and Secondary (electrons and non-electrons) tracks with the aim of characterizing the resolution, alignment and material budget in dependent from η, and .

The comparison of Monte-Carlo predictions for IP distributions

with Experimental results are good source of information for verification of ATLAS Geo Model for Inner Detector.

Impact parameters are one of the most important criterion for

reconstructed track selection.

d 0 z0(sinΘ) pT nsel

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Impact parameters and z0(sinΘ)

d 0 d 0 z0(sinΘ)

the signed distance to the z-axis
the z-coordinate of the track at the point of

closest approach to the global z-axis

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Track distribution for parameter

d 0

Run 2 for pp at 13 TeV Run 1 for pp 0.9 – 8 TeV

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Convolution of Gaussian with Gaussian for and

The beam spot resolution

for

The beam spot resolution

for

The beam spot resolution

for

C – normalization

parameter

and - resolution and

average of the IP

and - resolution

and average for beam spot

σ(d0) σBS(d 0)=σ BS σ(z 0sinΘ) σBS( z0)=σ BS cotgΘ σBS( z0sinΘ)=σBS cosΘ σBS σIP μBS μIP

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Resolution in depence from η for at 13 TeV

Reprocessing. Average of IP d0
Deconvolution. Resolution of IP d0

d 0

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Resolution in depence from for at 13 TeV

pT

Reprocessing. Average of IP d0
Deconvolution. Resolution of IP d0

d 0

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Charged-particle multiplicities at √s=13 TeV

Results of our investigation for impact parameters are included in

these distributions.

Absolutly new energy

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Conclusion

Impact parameters resolution are very important for correct track

selection.

IP resolution is twice better for Run2 than for Run1 geometry. It

means that background from secondary tracks are smaller.

The IP d0 and z0 sinΘ resolutions for experimental data are in good

agreement with MC prediction.

The IP d0 and z0 sinΘ averages for experimental data are in good

agreement with MC predictions.

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Thank you for your attention Thank you for your attention

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BACKUP SLIDES

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Selection of tracks

Cut parameter Cut value pT |η| Number of Silicon hits Number of Pixel hits Number of b-layer hits Number of tracks in PV Number of PVs Number tracks in PV Track Probability for pT>10 GeV > 0.5 GeV/c < 2.5 ≥ 6 ≥ 1 > 0 > 1 = 1 ≥ 2 ≥0.01

Selection cuts at 13 TeV

 Select only well-defined tracks,  Select a primary vertex to reduce error in IP.

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Track distribution for parameter

z0(sinΘ)

Run 2 Run 1

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Resolution in depence from for

nsel

Reprocessing. Average of IP d0
Deconvolution. Resolution of IP d0

d 0

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Resolution in depence from η for

Reprocessing. Average of IP z0sinΘ
Deconvolution. Resolution of IP z0sinΘ

z0(sinΘ)

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Resolution in depence from for

pT

Reprocessing. Average of IP z0sinΘ
Deconvolution. Resolution of IP z0sinΘ

z0(sinΘ)