Physics Commons^™

Beyond Standard Model: Neutrino-Antineutrino Pairs In Nuclear Reactions Of Beta-Decay And Proton-Neutron Transmutation., Polievkt Perov

College of Arts & Sciences Faculty Works

On examples of different beta-decay reactions, we show that the neutrino-antineutrino pairs should be added as necessary reagents to the equations of the decay reactions where a neutrino or an antineutrino is among the products of the reaction. In our models, quarks and leptons are all made of basic fractional +-e/3 charges. Transfer of basic charges between reagents forms the products of the reaction. We suggest that there is no direct conversion of u-quark to d-quark and visa versa. Each transmutation involves a transfer of basic charges from a neutrino to a quark so the structure of remaining charges in …

Study Of 134in Beta-Delayed Neutron Emission And Development Of A New Generation Neutron Detector, Joseph Heideman

Doctoral Dissertations

Beta-delayed neutron emission in very neutron-rich nuclei plays an essential role in nuclear structure and the understanding of the astrophysical r-process. A complete description of this process requires knowledge of both steps, beta decay and neutron emission. A leading theory poses the intermediate daughter nucleus to behave as a compound nucleus. The conditions for beta-delayed neutron emission of 134In are not well described by the assumptions in the neutron pandemonium hypothesis, therein providing a unique case to this process due to the proximity to 132Sn. Single-particle states in 133Sn obvserved after neutron emission have dissimilar shell occupancy compared to neutron-hole …

Search For The Decays Of 113ba, Yongchi Xiao

Doctoral Dissertations

The search for new alpha-emitters in the region above tin-100 was carried out in Japan Atomic Energy Agency (JAEA) tandem accelerator in Tokai, Japan. This work aimed to discover barium-113 produced via the fusion-evaporation reaction nickel-58(nickel-58,3n)barium-113 and observation through its alpha-decay chain from barium-113 to xenon-109 to tellurium-105 and tin-101. In the proof of principle experiment in March 2014, the alpha-decay chain of xenon-109 was observed with Double-sided Silicon Strip Detector (DSSD) and digital electronics at JAEA Recoil Mass Separator (RMS). The first discovery-oriented barium-113 experiment was carried out in December 2014 searching for its alpha-decay, ground-state to ground-state beta-decay …

Beta Decay Of Neutron-Rich Isotopes Of Zinc And Gallium, Mohammad Faleh M. Al-Shudifat

Doctoral Dissertations

Beta-decays of neutron-rich nuclei near the doubly magic ⁷⁸Ni [78Ni] were studied at the Holifield Radioactive Ion Beam Facility. The half-life and the gamma-gamma coincidence spectra were used to study the nuclear structure. A new ^82,83Zn [82Zn, 83Zn] decay-scheme was built, where a 71±7% beta-delayed neutron branching ratio was assigned in ⁸²Zn [82Zn] decay. New gamma-ray lines and energy levels observed in ^82,83Ga [82Ga, 83Ga] beta-decay were used to update previously reported decay-schemes. The experimental results were compared to shell model calculations, which postulate the existence of Gamow-Teller transitions in these decays. The half-lives of 155±17 …

Instrument For Precision Long-Term Ss-Decay Rate Measurements, M. J. Ware, Scott D. Bergeson, J. E. Ellsworth, M. Groesbeck, J. E. Hansen, D. Pace, J. Peatross

Faculty Publications

We describe an experimental setup for making precision measurements of relative ß-decay rates of ²²Na, ³⁶Cl, ⁵⁴Mn, ⁶⁰Co, ⁹⁰Sr, ¹³³Ba, ¹³⁷Cs, ¹⁵²Eu, and ¹⁵⁴Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM …

Search For A T-Odd, P-Even Triple Correlation In Neutron Decay, T. E. Chupp, R. L. Cooper, K. P. Coulter, S. J. Freedman, B. K. Fujikawa, A. Garcia, Gordon L. Jones, H. P. Mumm, J. S. Nico, A. K. Thompson, C. A. Trull, F. E. Wietfeldt, J. F. Wilkerson

Articles

Background: Time-reversal-invariance violation, or equivalently CP violation, may explain the observed cosmological baryon asymmetry as well as indicate physics beyond the Standard Model. In the decay of polarized neutrons, the triple correlation D⟨⃗Jn⟩/Jn⋅(⃗βe׈pν) is a parity-even, time-reversal-odd observable that is uniquely sensitive to the relative phase of the axial-vector amplitude with respect to the vector amplitude. The triple correlation is also sensitive to possible contributions from scalar and tensor amplitudes. Final-state effects contribute to D at the level of 10−5 and can be calculated with a precision of 1% or better.

Purpose: We have improved the sensitivity to T-odd, P-even …

Beta-Decay, Beta-Delayed Neutron Emission And Isomer Studies Around 78Ni, Mustafa Moiz Rajabali

Doctoral Dissertations

A study of nuclei with few nucleons outside the closed shell provides benchmarks for the nuclear shell model especially in this modern era of physics where exotic doubly magic nuclei can be tested. The subject of this thesis is to experimentally investigate the properties of nuclei near ⁷⁸Ni and to confront them with the predictions of modern large scale shell model calculations. In this regard, an experiment was performed at the National Superconducting Cyclotron Laboratory (NSCL) to measure excited states in ^71-73Ni populated via the beta-decay of ^71-73Co. Data collected from this experiment lead to partial level …

Emit: An Apparatus To Test Time Reversal Invariance In Polarized Neutron Decay, H. P. Mumm, A. Garcia, L. Grout, M. Howe, L. P. Parazzoli, R. G. H. Robertson, K. M. Sundqvist, J. F. Wilkerson, S. J. Freedman, B. K. Fujikawa, L. J. Lising, M. S. Dewey, J. S. Nico, A. K. Thompson, T. E. Chupp, R. L. Cooper, K. P. Coulter, S. R. Hwang, R. C. Welsh, L. J. Broussard, C. A. Trull, F. E. Wietfeldt, Gordon L. Jones

Articles

We describe an apparatus used to measure the triple-correlation term (D (σ) over cap (n).p(e)xp(nu)) in the beta decay of polarized neutrons. The D coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. A beam of longitudinally polarized cold neutrons passes through the detector chamber, where a small fraction undergo beta decay. The final-state protons are accelerated and focused onto arrays of cooled semiconductor diodes, while the coincident electrons are detected using panels of plastic scintillator. Details regarding the design and performance of the …

New Limit On The D Coefficient In Polarized Neutron Decay, L. J. Lising, S. R. Hwang, J. M. Adams, T. J. Bowles, M. C. Browne, T. E. Chupp, K. P. Coulter, M. S. Dewey, S. J. Freedman, B. K. Fujikawa, A. Garcia, G. L. Greene, Gordon L. Jones, H. P. Mumm, J. S. Nico, J. M. Richardson, R. G. H. Robertson, T. D. Steiger, W. A. Teasdale, A. K. Thompson, E. G. Wasserman, F. E. Wietfeldt, R. C. Welsh, J. F. Wilkerson

Articles

We describe an experiment that has set new limits on the time reversal invariance violating D coefficient in neutron beta decay. The emiT experiment measured the angular correlation [J] . (p(e) x p(p)) using an octagonal symmetry that optimizes electron-proton coincidence rates. The result is D=[-0.6+/-1.2(stat)+/-0.5(syst)] x 10(-3). This improves constraints on the phase of g(A)/g(V) and limits contributions to T violation due to leptoquarks. This paper presents details of the experiment, data analysis, and the investigation of systematic effects.

Laser Oriented K-36 For Time-Reversal Symmetry Measurements, A. R. Young, W. S. Anderson, F. P. Calaprice, G. D. Cates, Gordon L. Jones, D. A. Krieger, R. B. Vogelaar

Articles

We have produced very large nuclear alignments in radioactive K-36 (half-life 0.34 sec) through laser optical pumping techniques. The K-36 was created through (p,n) reactions using a 50 nA, 22 MeV proton beam, and a 3.3 atmosphere Ar-36 target. Measurements were made with the target cell at room temperature, when direct optical pumping produces nuclear orientation in the K-36, and at elevated temperatures 160 degrees C and 180 degrees C) where the K-36 is oriented through a combination of direct optical pumping and spin exchange. The fraction of the maximal nuclear alignment for the 180 degrees C data was determined …