Matching Items (2)
Filtering by
- All Subjects: CP violation (Nuclear physics)
- Creators: Alarcon, Ricardo
Description
This thesis deals with the first measurements done with a cold neutron beam at the Spallation Neutron Source at Oak Ridge National Laboratory. The experimental technique consisted of capturing polarized cold neutrons by nuclei to measure parity-violation in the angular distribution of the gamma rays following neutron capture. The measurements presented here for the nuclei Chlorine ( 35Cl) and Aluminum ( 27Al ) are part of a program with the ultimate goal of measuring the asymmetry in the angular distribution of gamma rays emitted in the capture of neutrons on protons, with a precision better than 10-8, in order to extract the weak hadronic coupling constant due to pion exchange interaction with isospin change equal with one ( hπ 1). Based on theoretical calculations asymmetry in the angular distribution of the gamma rays from neutron capture on protons has an estimated size of 5·10-8. This implies that the Al parity violation asymmetry and its uncertainty have to be known with a precision smaller than 4·10-8. The proton target is liquid Hydrogen (H2) contained in an Aluminum vessel. Results are presented for parity violation and parity-conserving asymmetries in Chlorine and Aluminum. The systematic and statistical uncertainties in the calculation of the parity-violating and parity-conserving asymmetries are discussed.
ContributorsBalascuta, Septimiu (Author) / Alarcon, Ricardo (Thesis advisor) / Belitsky, Andrei (Committee member) / Doak, Bruce (Committee member) / Comfort, Joseph (Committee member) / Schmidt, Kevin (Committee member) / Arizona State University (Publisher)
Created2012
Description
Seeking an upper limit of the Neutron Electric Dipole Moment (nEDM) is a test of charge-parity (CP) violation beyond the Standard Model. The present experimentally tested nEDM upper limit is 3x10^(26) e cm. An experiment to be performed at the Oak Ridge National Lab Spallation Neutron Source (SNS) facility seeks to reach the 3x10^(28) e cm limit. The experiment is designed to probe for a dependence of the neutron's Larmor precession frequency on an applied electric eld. The experiment will use polarized helium-3
(3He) as a comagnetometer, polarization analyzer, and detector.
Systematic influences on the nEDM measurement investigated in this thesis include (a) room temperature measurements on polarized 3He in a measurement cell made from the same materials as the nEDM experiment, (b) research and development of the Superconducting QUantum Interference Devices (SQUID) which will be used in the nEDM experiment, (c) design contributions for an experiment with nearly all the same conditions as will be present in the nEDM experiment, and (d) scintillation studies in superfluid helium II generated from alpha particles which are fundamentally similar to the nEDM scintillation process. The result of this work are steps toward achievement of a new upper limit for the nEDM experiment at the SNS facility.
(3He) as a comagnetometer, polarization analyzer, and detector.
Systematic influences on the nEDM measurement investigated in this thesis include (a) room temperature measurements on polarized 3He in a measurement cell made from the same materials as the nEDM experiment, (b) research and development of the Superconducting QUantum Interference Devices (SQUID) which will be used in the nEDM experiment, (c) design contributions for an experiment with nearly all the same conditions as will be present in the nEDM experiment, and (d) scintillation studies in superfluid helium II generated from alpha particles which are fundamentally similar to the nEDM scintillation process. The result of this work are steps toward achievement of a new upper limit for the nEDM experiment at the SNS facility.
ContributorsDipert, Robert (Author) / Alarcon, Ricardo (Thesis advisor) / Chamberlin, Ralph (Committee member) / Golub, Robert (Committee member) / Chen, Tingyong (Committee member) / Schmidt, Kevin (Committee member) / Arizona State University (Publisher)
Created2019