[Physics-grads-open] PASS talk Monday Nuclear Physics

[Pooyan Goodarzi]

Hi all,

We will have a PASS talk tomorrow by Ananya. Please join us 
at noon (from 12:00 pm to 1:00 pm) in the Nebula Room (PHYS 3027).


*Ananya Paul**, PhD student*
Monday, 12:00 pm, Nebula Room (PHYS 3027)
*Measurement of the Transverse Single Spin Asymmetry (TSSA) of Neutral 
pions using transversely polarised proton-proton collisions (COM 200 
Gev) detected at the Endcap Electromagnetic Calorimeter (EEMC) at STAR, 
Brookhaven National Laboratory*

   In recent years, endeavours have been made towards extending the 1D 
Feynman parton picture to a 3D tomography of the partons inside the 
nucleon. The transverse nucleon spin i.e. the spin component 
perpendicular to the nucleon momentum direction correlates naturally 
with the Transverse Momentum-Dependant (TMD) parton distributions as 
well as the Generalised Parton Distributions (GPD), hence providing a 
deep insight into the internal structure and parton correlations of the 
nucleon. The Transverse Single Spin Asymmetry (SSA) is defined as an 
asymmetry between counting rates for a given reaction for either the 
probe or the target transversely polarised.  High Energy Experiments 
show that the charged pions are produced asymmetrically to the left or 
the right of the plane spanned by the momentum and spin directions of 
the initial polarized protons:

              AN = dσ(S⊥) - dσ(-S⊥)/dσ(S⊥) + dσ(-S⊥)


Therefore, this asymmetry is also called left-right asymmetry. AN is 
quantified by the TMD quark Sivers function and the GPD function in the 
transverse direction by asserting that the spin-averaged quark 
distributions are symmetric in the transverse plane. Moreover, if the 
nucleon (or the quark) is transversely polarised, the quark distribution 
is azimuthally asymmetric in the transverse plane. Therefore, transverse 
spin phenomena enables the exploration of QCD dynamics of quarks and 
gluons in hadron structure, to test advanced concepts of QCD 
factorization and to test the universality of parton distribution 
functions between different high-energy scattering processes.  The goal 
of this study is to measure the Transverse Single Spin Asymmetry (AN ) 
of neutral pions (π⁰) with the STAR Endcap Electromagnetic Calorimeter. 
In the past, measurements for AN  have been made at forward rapidity 
(3.3 < η < 5.5) and mid-rapidity with asymmetries consistent with zero 
for the latter. With the STAR Endcap Electromagnetic Calorimeter 
providing an azimuthal coverage over the pseudorapidity range 1.086 ≤ η 
≤ 2.00, the determination of AN  at intermediate rapidities will be 
achieved.



If you’re interested in sharing your work as a speaker, please feel free 
to add your name to this spreadsheet [Google Sheet 
<https://docs.google.com/spreadsheets/d/1N3ncf43jdB6aHYHhyWmyHMycxDg4_phHZXLkQvviO0o/edit?usp=sharing>]. 
Recordings of all the previous talks are available at our website: 
https://ucrpass.arxiv.social


Best,
Pooyan
Physics and Astronomy Student Seminar (PASS)
https://ucrpass.arxiv.social
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