Elementary Particles and Fields and String Theory Commons^™

A Study Of Data/Monte Carlo Agreement In Charmed Baryon Decays At Belle Ii, Kaitlyn Thurmond

Honors Theses

The Belle II experiment at the SuperKEKB electron-positron accelerator facility in Tsukuba, Japan has a primary goal of searching for new physics beyond the Standard Model of particle physics. Extremely precise measurements of particle decays will be compared with Standard Model predictions in order to expose the presence of new particles and interactions. These measurements are prepared using simulated samples to avoid potential biases when studying the data. The Belle II collaboration produces two types of simulated samples for this purpose. One is produced with consistent calibration payloads and another with payloads calibrated as a function of data taking. This …

An Analysis Of Detection Asymmetry Using Baryon Decays In Belle Ii, Matthew Mestayer

Honors Theses

The purpose of this study was to determine the detection asymmetry of the Belle II detector using decays of two common baryons, Λ⁰ → ��π^- and Σ⁺ → ��π⁰. A Monte Carlo simulation of both decays was used to determine the validity of signal isolation criteria. These criteria were then applied to the Belle II data, allowing for a comparison of the detection asymmetry in the data relative to the simulation. The results show a moderate detection asymmetry when using the Λ⁰ → ��π^- decay, particularly for forward-going baryons. For the Σ^{+ …}

Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen

Honors Theses

At Jefferson Lab we use the CLAS12 detector to measure the neutron magnetic form factor. An accurate measurement of the CLAS12 neutron detection efficiency (NDE) is required. We use the nuclear reaction ���� → ��′��+�� as a source of tagged neutrons and obtain the NDE from the ratio of expected neutrons to detected ones. We assume the final state consists of ��′��+�� only, use the ��′��+ information to predict the neutron's position(expected) and then search for that neutron(detected). We select neutrons with the missing mass (MM) technique. We use simulation to validate our methods. We simulated events with the Monte-Carlo …

Lifetime Measurement Of The Xi_C^+ Using Belle Ii Monte Carlo, Paul Gebeline

Honors Theses

This analysis uses simulated data from the Belle II experiment to measure the lifetime of the Xi_c^+ baryon. Three different decay modes are investigated to explore the feasibility and accuracy of such measurements at Belle II. The Xi_c^+ lifetime is measured using one of these modes after reducing backgrounds from sources other than the decay of interest. The final result is 464 +/- 15 fs, which is consistent with the expected result of 442 fs within uncertainty. This result shows that Belle II can make competitive measurements of particle properties and decays.

A Performance Analysis Of The Belle Ii Detector, John Stacy

Honors Theses

The Belle II experiment has recently (2018) started data taking at the SuperKEKB electron-positron collider in Tsukuba, Japan. Detector performance studies are necessary to understand early data and prepare for more complex analyses. This study of the proton detection efficiency of the Belle II detector compares real and simulated data to find discrepancies with the intention to provide useful information for detector and calibration experts to better gauge detector performance. It also attempts to improve the characterization of proton identification efficiency at low momenta, which performs poorly under the current fitting model. This helps analysts exploring final states that include …

Monte Carlo Study Of Lepton Flavor Universality Violation In B Decays With Belle Ii Simulation, Sakul Mahat

Honors Theses

Belle II, the first super B-Factory experiment, is designed to make precise measurements of weak interaction parameters and search for New Physics beyond the Standard Model of particle physics. The Standard Model of particle physics is a theory that classifies all known elementary particles and describes three of the four known fundamental forces in the universe. Physics beyond the Standard Model that addresses the theoretical developments needed to explain the deficiencies in the Standard Model is often referred to as New Physics. One of the assumptions of the Standard Model is that the couplings of particles that mediate the weak …

Analysis Of Possible Hybrid Meson Decay, Jasper Bergh

Honors Theses

This research looked at data from the GlueX experiment at the Thomas Jefferson National Accelerator Facility to search for evidence of the π1(1600) particle, an exotic hybrid meson, decaying to an eta' and π0. We specifically looked into decays of the eta' to an eta, π+, and π-, with the eta decaying to 3 πo's. We successfully reconstructed an eta from the 3 πo's, and an eta' from the eta, π+, and π-. However, we did not observe the π1(1600), but, a 6:1 ratio of signal to background in the eta' mass. With more statistics this would be a viable …

Curved Spacetime In The Causal Set Approach To Quantum Gravity, Ayush Dhital

Honors Theses

Causal Set theory is an approach to quantum gravity. In this approach, the spacetime continuum is assumed to be discrete rather than continuous. The discrete points in a causal set can be seen as a continuum spacetime if they can be embedded in a manifold such that the causal structure is preserved. In this regard, a manifold can be constructed by embedding a causal set preserving causal information between the neighboring points. In this thesis, some of the fundamental properties of causal sets are discussed and the curvature and dimension information of Minkowski, de Sitter, and Anti-de Sitter spaces is …

Exploring Manifoldlike Causal Sets And Their Dimensions, Santosh Bhandari

Honors Theses

Causal Set Theory is an approach to quantum gravity that tries to replace the continuum spacetime structure of general relativity with the spacetime that has the property of discreteness and causality. From the standpoint of causal set theory, our spacetime is made up of discrete points that are causally related to one another. A causal set is said to be manifoldlike if it can be faithfully embedded in a Lorentzian manifold. In this thesis, some of the fundamental properties of causal sets are discussed. The first chapter is devoted to the historical background of quantum gravity with a discussion of …

Massive Gravity Theories, Greg Seyfarth

Honors Theses

We examine Fierz and Pauli's work in 1939 of adding a mass term to the Lagrangian for linearized gravity with the form ?? where h is a small perturbation away from flat spacetime and showing that the only value for ? which gives a ghost-free theory with the correct five degrees of freedom expected for a massive spin- 2 particle such as the graviton is ? [1]. We start by rederiving the Lagrangian formulation for classical electrodynamics and giving examples of a ghost. Then we solve the linearized massless gravity equations to show their two degrees of freedom. We perform …

Vector Theory Of Spontaneous Lorentz Violation, Shu Hong Fung

Honors Theses

Classical electromagnetism predicts two massless propagating modes, which are known as the two polarizations of the photon. On the other hand, if the Lorentz symmetry of classical electromagnetism is spontaneously broken, the new theory will still have two massless Nambu-Goldstone modes resembling the photon. If the Lorentz symmetry is broken by a bumblebee potential that allows for excitations out of the minimum, then massive modes arise. Furthermore, in curved spacetime, such massive modes will be created through a process other than the usual Higgs mechanism because of the dependence of the bumblebee potential on both the vector field and the …

Dynamic Phase Steepening In Alfven Waves, Stephen R. Granade

Honors Theses

Our solar system contains more activity and complexity than can be seen through a telescope. One such "invisible" phenomenon is the solar wind, created by a steady stream of particles blasted away from the sun in all directions. The sun's donut-shaped magnetic field lines channel this stream. Particles moving along the field lines perform an intricate helical dance, with ions winding one way and electrons the other.

The solar wind shapes and is shaped by the magnetic fields of the planets and the sun. If left undisturbed by outside influences, the earth's magnetic field, like the sun's, would resemble a …