Abhinav Vedmala

1/28/2021 - Project Preference Selection & Research

(#) represents the order of preference

(4) Top Quark Properties - Studying the properties of Top Quarks at LHC. The top quark is the most massive of all elementary particles. Since the top quark is the heaviest of all particles, the interaction between the Higgs boson and top quarks is also the strongest. Tools such as MadGraph will be used to study models and simulate particle collision.

(2) IceCube - The IceCube Observatory searches for nearly massless subatomic particles called neutrinos. These high-energy astronomical messengers provide information to probe the most violent astrophysical events like exploding stars, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars. Project involves data analysis which is something I'm interested in.

(1) LZ Next Generation Dark Matter - The LZ Experiment takes place deep underground at the Sanford Research Facility. Dark matter doesn't interact with electromagnetic radiation so liquified Xenon is used to interact with the dark matter which releases energy imparted to the Xenon nucleus as charged particles and electromagnetic radiation. The project entails calibrating observed energy and developing software to analyze the data in Python and ROOT. ROOT is an object-oriented program and library developed by CERN for particle physics data analysis.

Segmented Crystal Calorimeters - 

(3) Computing - UMD hosts a local Tier 3 of the Worldwide LHC Computing Grid (WLCG). Tier 3 computing resources allow individuals to access the Grid. Tools such as Puppet and Foreman are used for automatic software deployment and configuration. overt is the Virtual Machine manager which handles several dozen VMs. Ganglia and Dell OMSA are used to monitor the hardware (disk temperatures, network, memory, disk and CPU usage, etc.). This is a pure computing project and as a CS major that alone interested me.

Student Arranged - Emailed a few professors that work in ML & Data Science to find an advisor. Not sure exactly what I want to do but I have been interested in Algorithmic Trading. I don't think any professors specialize in that so I would need another topic. Dickerson did get back to me and said he was too busy this semester.

2/4/2021 - Intro Presentation

My topic is the LZ Experiment. Working with Zach Dorris and Jacob Clements under Professor Anwar Bhatti. Below are the notes I took before creating my slides.

Background

The LZ (LUX-ZEPLIN) Experiment aims to build the most sensitive dark matter detector ever. 

It’s 30 times larger and at least 100 times more sensitive than its predecessor, the Large Underground Xenon (LUX) experiment. It’s also built on the foundation of ZEPLIN, another dark matter experiment at the Boulby Underground Lab in the UK.

Explanation

All these experiments are conducted deep underground to shield from unwanted particles that cause background noise. Going underground as opposed to the surface eliminates these particles by a factor of 10 million. It’s also housed in a water shield containing 70,000 gallons of purified water to further reduce external background signals.

The LZ is a titanium vessel filled with 10 tonnes of xenon. LUX was around 350kg so this is where that 30 times larger figure comes from.

During particle collision, a small amount of energy is transferred to the xenon nucleus. When this energy is released, a flash of light is emitted along with free electrons. This flash of light is called scintillation. These particles can be particles we already know about (beta particles, neutrons) or they could also be dark matter particles that interact very weakly. (WIMPs).

Photomultiplier tubes are placed above and below the xenon to sense the bursts of light. The amount of light emitted from the scintillation allows scientists to determine what type of particle it is. By eliminating the ones we already know about, we can look for WIMPs.

More specifically, if a dark matter particle collides with a xenon atom, it produces a second flash of light after the initial scintillation when the free electrons produced in the liquid xenon chamber drift to its top.

Challenges

As previously mentioned, eliminating background noise is extremely important. All components of LZ are measured for naturally occurring radiation to account for false signals. The titanium vessel which houses the liquid xenon is built with the world’s most ultra-pure titanium. The water shield housing the titanium vessel has another array of photomultiplier tubes to veto more false signals.

Why

The Universe has five times more dark matter than normal matter. Something so plentiful plays a huge role in our Galaxy and Universe. This research may not have an everyday practical application but knowing what our Universe is made of gives us a huge advantage in the future.

Being so common, it’s estimated that a 2-liter bottle of Pepsi would have one dark matter particle within its volume. It’s also speculated that there’s more of it in the center of the Galaxy as it interacts gravitationally.

Links

https://sanfordlab.org/article/lux-zeplin-new-experiment-hoping-detect-dark-matter

https://sanfordlab.org/experiment/lz-experiment

https://lz.lbl.gov/laboratory/

http://hepcms-hn.umd.edu/~bhatti/

4/1/2021 - Generating Plots

Prof. Bhatti shared new data with us so we had to generate new sets of plots and histograms. He gave us two sets of data: H3 and BG which are simulated dark matter events and background events. These are located at "/data2/users/bhatti/lz/BG/" and "/data2/users/bhatti/lz/H3/". There are multiple subfolders with data from different days so we just choose the most recent ones.

1. Copy the files from Prof. Bhatti's HONR269L directory into your own home directory. This is done because you only have read access in his directory. This can be done with `cp /home/bhatti/HONR269L/ ~/HONR269L`. Just make sure you have a folder ~/HONR269L, if you don't, you can run `mkdir ~/HONR269L`.

2. We want to change the input to the BG and H3 data and this can be done by going to line 160 of "WIMP_DataRQ_V3.cc" and changing the path to the path mentioned in step (1).

3. Now run the following commands to setup the environment: `bash`, `source setup.sh`. Now run `root.exe` to open up a root window.

4. Inside root, you must execute all the commands inside "WIMP_DataRQ.C".

   • `gSystem->Load("${ROOTSYS}/lib/libPhysics.so");`

   • `gSystem->AddIncludePath(" -I/cvmfs/lz.opensciencegrid.org//LZap/release-5.1.0/x86_64-centos7-gcc8-opt/include/");`

   • `gSystem->Load("/cvmfs/lz.opensciencegrid.org//LZap/release-5.1.0/x86_64-centos7-gcc8-opt/lib/libRQLib.so");`

   • `gSystem->CompileMacro("WIMP_DataRQ_V3.cc");`

   • `WIMP_DataRQ();`

5. Now you just need to open up the root browser. While still in root, type the following:

   • `TFile f("WIMP_DataRQ_plots.root")`

   • `TBrowser b`

6. A ROOT Object Browser will open up. If nothing opens up, make sure XQuartz is install if you're on MacOS. Double click on the .root file on the left side bar and all the plots will show.