August 23, 2021 to October 7, 2021
Venue: OAC conference center, Kolymbari, Crete, Greece. Participation is possible also via internet.
Europe/Athens timezone

Differential measurements of jet sub-structure observables and their correlation in p+p collisions at √s=200 GeV in STAR

Sep 1, 2021, 1:00 PM
Room 1

Room 1


Monika Robotková


Jets are collimated sprays of hadrons created by the fragmentation of high energy partons, and serve as an experimental tool for studying quantum chromodynamics. In particular, we can explore the properties of parton showers and jet evolution by measuring jet sub-structure. One of the techniques that allows experimental access to the parton shower is the jet grooming technique called SoftDrop. This analysis extends recent measurements of the jet sub-structure observables based on the SoftDrop algorithm in p+p collisions at $\sqrt{s}$ = 200 GeV in the STAR experiment, including groomed radius ($R_{g}$) and shared momentum fraction ($z_{g}$). We present fully unfolded multi-differential measurements of jet sub-structure observables at the first split and their corresponding correlations via $z_{g}$ vs. $R_{g}$ for jets of different transverse momenta and radii. We show that $z_{g}$ has a strong dependence on $R_{g}$ and a weak dependence on jet transverse momentum. To further explore the jet sub-structure, we present the first measurement of the jet shower at the first, second and third splits via the iterative SoftDrop procedure. For each of these splits, we measure the fully corrected $z_{g}$ and $R_{g}$. We compare our measurements to the state-of-the-art Monte Carlo models. We discuss the impact of variations in parton shower (perturbative) and hadronization/underlying-event (non-perturbative) modeling on the measured correlations between sub-structure observables. We will also preview upcoming measurements that explore the splitting scale ($k_{T}$) and groomed mass fraction ($\mu$) in our differential framework.


Monika Robotková
Nuclear Physics Institute of the CAS
Czech Republic

Is this abstract from experiment? Yes
Name of experiment and experimental site STAR Collaboration
Is the speaker for that presentation defined? Yes
Internet talk No

Primary author

Monika Robotková

Presentation materials