Session B01: High Energy Physics: Experiment and Theory

A Potential Method for the Production of Ice-XI for Low Mass Dark Matter Detection

For nearly a century, dark matter has been a topic of excited debate and remains an area of active research. Currently, there are three main avenues of dark matter detection: direct detection, indirect detection for example of decay products, or production in particle accelerators. We focus on a specific material that could be used in the first of these. Ice-XI is a hydrogen-ordered phase of water ice that forms at low temperatures. It is a particularly promising target for use in direct detection of light dark matter, specifically single phonon detection. We describe an attempt to make ice-XI employing minimal specialty equipment: using a KOH dopant and maintaining the sample at or below 72 K for several days via an LN2 bath in a vacuum chamber. The phase transition from ice-Ih to ice-XI is monitored through dielectric measurements of capacitors embedded in the ice samples.

Two week-long tests were performed using ice doped with 0.01 M and 0.05 M KOH. We observed no change in the 0.01 M test, but saw a slight increase in capacitance for the 0.05 M test. From previous studies, we expected the ice-XI phase transition to be accompanied by a rapid decrease in capacitance. Our results indicate that the phase transition did not occur in either test. However, some previous studies observed an initial slight increase before the main decrease in capacitance associated with the phase transition. Therefore, we suspect that this initial transition stage may have occurred in the 0.05 M test, and had the test been left to run longer, we may have observed the main stage of the transition as well.  

While we were unsuccessful in documenting the transition, we believe the methodology to be sound. In future iterations of the experiment, we would either perform the test for longer time periods, or try some combination of higher KOH concentrations, colder temperatures, and/or smaller ice samples which could all accelerate the transition, making it more readily observable with our setup.    

Ongoing Commissioning of the ToF Detector for the T2K ND280 Upgrade

The T2K ND280 upgrade aims to reduce systematic uncertainties affecting the oscillation analysis, enhancing the experiment’s sensitivity to CP violation in the lepton sector. As part of this upgrade, the existing $\pi^0$ detector (P0D) is replaced with three new detectors: the Super Fine-Grained Detector (SFGD) sandwiched between two High-Angle Time Projection Chambers (HA-TPCs), all enclosed by the Time-of-Flight (ToF) detector. The ToF detector plays a crucial role by providing precise timing information for particle tracks, allowing for the discrimination of background particles from those generated within the fiducial volume, thereby reducing one of the main backgrounds in ND280 analyses.

This project focused on examining the first cosmic-ray and beam data (sand muons) recorded by the newly installed ToF detector, which is essential for its tuning and calibration. Preliminary results revealed a misalignment in the ToF system and provided insights into beam behavior, both critical for ongoing detector commissioning. These findings will help optimize the ToF detector’s performance, ensuring it meets the upgrade’s goals of improved particle identification and reduced background noise in future analyses. By addressing this issue, the calibration process can now be fine-tuned, ensuring that future analyses of particle interactions are more reliable.    

Performance Study of the Scattering Neutrino Detector at the Large Hadron Collider

The Scattering Neutrino Detector at the Large Hadron Collider (SND@LHC) is a compact stand-alone experiment aiming to measure high energy neutrino cross section. The data acquisition is triggerless. The detector has nuclear emulsions and electronic detectors, allowing for a detailed measurement of neutrino interactions at energies never studied before (1 TeV) in a specific region of space that larger detectors cannot access. My research focused on event building from raw data sets and testing the parameters of employed event building strategies through many different analyses to further our understanding of the performance of the detector. This ensures that relevant physics such as neutrino interactions are present and not cut out of the event. This was done through the investigation of the timestamps of events, testing different noise filters, determining the efficiency of employed event building, and muon tracking. My research showed there are dips in the timestamps of the event building data due to the calibration policy. This creates a new potential research investigation to smooth out this data. I further confirmed that two currently employed noise filter settings work as intended, and performed muon flux measurements showing that the employed event building is robust.   

Designing a High Pressure Rinse Mount for Superconducting Material Samples

Superconducting radio frequency (SRF) cavities, used to accelerate a charged particle beam, are one of the vital organs of an accelerator --- improving their performance allows for higher beam energies, which opens new frontiers in various branches of science and medicine. The material properties of the superconductors used to make these SRF cavities are one of the major factors in determining how well they will perform in an actual accelerating structure. The Cornell High Pulsed Power Sample Host Cavity (CHPPSHC) is a system recently commissioned by our research group. Its purpose is to test the material limits of candidate SRF materials with samples. These samples must be extremely clean before they can be assembled into the sample host cavity. Typically, we use a high pressure rinser with high purity de-ionized water to clean accelerating cavities. This particular sample geometry could not be accommodated by our system without design and fabrication of a new mount. In this paper I introduce this new mount along with considerations that went into its design.   

Photon-fusion production of spin-even bound states at hadron colliders

The cross sections for the production of scalar, pseudoscalar, and tensor mesons, as well as of bound spin-even systems formed by pairs of opposite-charge leptons or hadrons, are estimated for photon-photon fusion processes in ultraperipheral collisions (UPCs) of proton-proton, proton-nucleus, and nucleus-nucleus at the  RHIC, LHC and FCC colliders.

The UPC cross sections are computed in the equivalent photon approximation with realistic photon fluxes from the charged form factors of proton, lead, and gold ions. The production of three types of spin-even onium systems are considered: quarkonium (spin even meson resonances),  leptonium (positronium, dimuonium, and ditauonium), and hadronium QED atoms (pionium, kaonium, protonium, and D-onium) states.   

Pion Structure in the Covariant Parton Model

We present a theoretical introduction to parton distribution functions (PDFs) and other related distributions used to model the internal structures of subatomic particles on an elementary scale. We also introduce the so-called covariant parton model (CPM) and explain how to use the model to calculate the distributions of interest. Using data from the HERA collider with JAM parametrization, we perform these calculations for pions in the CPM.  By providing an outlook on our CPM project, we aim to provide theoretical background to experimental and lattice QCD calculations.