Jiaqi Jiang

Undergraduate Student: Class of 2015
Major: Physics, Mathematics
Hometown: Shanghai, China
Awards: Selove Summer Research Prize, Phi Beta Kappa
Research: Astrophysics, high-energy physics
Research Advisors: Donald York (ASTR), Paolo PriviteraMark Oreglia

I have been involved in various physics research projects as an undergraduate. The projects cover topics from astrophysics to high energy physics. During my participation in the research, Professor York, Professor Privitera and Professor Oreglia all provided me with great help and support. From these research experiences, I have both developed different research skills and acquired a deeper understanding of the physics involved in those projects.

Since the winter quarter of my freshman year, I have been working with Professor Donald York on the study of diffuse interstellar bands (DIBs). DIBs are relatively broad absorption bands appearing in the spectra of stars behind interstellar matter. These bands are most likely to be caused by large molecules, whose identities still remain unknown. I use a computer program to measure the various characteristics of known DIBs, including the equivalent width, full widths at half maximum and central wavelength seen in the spectra of stars of different spectral types. The aim of this work is to develop the biggest data catalog for these known DIBs. Since the beginning of this year, I have begun to study the properties of DIBs in the spectra of the latest 2014 supernova. I modified the various features of the previous computer program to adapt to the measurement of DIBs in supernova because the blending of DIBs from different interstellar medium components make the absorption features much wider than in the spectra of other stars. By comparing the data measured in the supernova spectra with the data of DIBs from our galaxy, I try to classify DIBs into different types and explore the different behavior of certain DIBs in the supernova.

During the last summer, I participated in Professor Paolo Privitera's research on ultra-high-energy cosmic rays (UHECR). UHECRs are very energetic particles originating outside of the solar system with a kinetic energy greater than 10^19 eV. In particular, I am involved in the project of developing the Fluorescence Detector Array of Single-pixel Telescopes (FAST). The Pierre Auger Observatory, the largest cosmic ray detector so far, consists of 24 fluorescence telescopes, each utilizing an array of 440 photomultiplier tubes (PMT). The goal of FAST is to use arrays of fluorescence telescopes with a single PMT to cut down the costs. My work is focused on the calibration and precise measurement of characteristics of PMTs in the laboratory, including the linearity and stability of gain against the background noise. These measurements can help us select the best PMTs for our prototype model and better understand the performance of the detector. At the beginning of this year, I helped assemble our first single-pixel telescope model. Later on, with my research group, I visited the Telescope Array in Delta, Utah, and helped the operation of the field test for our prototype telescope. Having obtained the data from the field test at Utah, I am now concentrating on implementing new features in the data analysis software for FAST. Recently, I have been using simulations to study the performance of FAST and using the simulation data to develop the shower reconstruction program for the telescopes.

In addition to the research in astrophysics, I am also interested in high energy experiments. Since April of 2014, I started to work with Professor Oreglia on a data analysis project on the ATLAS experiment. The aim of this project is to search for the exotic decay of the Higgs particle into two new particles. So far, I have done the analysis on the simulation data. In the next step, I will look at the real data and complete the analysis.