Summer Internship: Shiksha Pandey '22

August 25, 2021

Name: Shiksha Pandey
Class Year: 2022
Major: Physics, Mathematics
Hometown: Bharatpur, Nepal

Internship Organization: CERN
Job Title: Summer Student
Location: Internship carried out form Melrose, Mass. (Internship organization is located in Switzerland.)

What’s happening at your internship?

My project was on the investigation of the kinematics of di-Higgs signal in the HH->bbWW->bbqqqq (0-lepton) channel with the ATLAS detector at the Large Hadron Collider. This channel hadn’t been studied previously.

There are four fundamental forces in nature—the strong force, the weak force, the electromagnetic force, and the gravitational force. And then there are the fundamental particles: fermions or matter particles, bosons or force carrying particles, and the Higgs boson. Apart from gravity, all the above-mentioned entities can be described using a framework called the standard model of particle physics. Among others, the Higgs boson is a unique particle that gives mass to other fundamental particles through a process called the Higgs mechanism. It also interacts or couples with itself, and we look at different modes of di-Higgs production and decay to study that.

My research project was focused on a specific case of di-Higgs decay where the final products are four light quarks and two beauty quarks. Utilizing a monte carlo simulation, I analyzed the kinematics and identified various selection cuts that could be employed to improve the sensitivity of the signal. In addition, in this decay channel, two W bosons are involved and one of them is virtual. Virtual here means that it has a mass that is different from the ordinary W boson, and it violates the energy momentum relation temporarily. These W bosons aren’t directly detected since they decay into quarks. Using mass reconstruction, I identified which pair of quarks come from which W boson.

Why did you apply for this internship?

I’m interested in high energy physics and at Bryn Mawr, I have worked with Professor Michael Schulz in projects in high energy theory. So I thought it would be great to work on a computational or experimental project in that field. Realizing there could not be a better place than CERN to explore that, I applied for the internship position.

What has been the biggest challenge you have faced at your internship?

For the internship, I needed to know some C++ and ROOT. Since I hadn’t used them prior to this, it took me a while to equip myself with the necessary skills and actually start working on my project. Moreover, there were some lecture sessions on topics related to high energy physics that I couldn’t be an active participant in due to the time difference. Most importantly, it was challenging in general to keep up with tasks and meet with my supervisor because of the virtual nature of the internship and the time difference.

Can you give us three adjectives and three nouns that describe your internship experience?

Challenging. Rewarding. Pioneering.
The Higgs Boson. Programming. Kinematics.

Visit the Summer Internship Stories page to read more about student internship experiences.

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