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

[Pooyan Goodarzi]

Reminder: happening in ~2 hours.

On 4/6/25 5:13 PM, Pooyan Goodarzi wrote:
>
> 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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