Elementary Particles and Fields and String Theory Commons^™

Building An Alpha Spectrometer For The Cuore Collaboration, David J. Miller

Physics

This paper will give the reader a brief introduction to the Standard Model, Neutrinoless Double Beta Decay (0νββ), and the CUORE experiment under construction at Gran Sasso National Lab in Assergi, Italy. The remainder of the paper will describe the process of creating a working alpha spectrometry system using silicon detectors and NIM and CAMAC electronics. Extensive details of the troubleshooting and calibration period are presented as a way for the reader to better understand the concepts involved in alpha spectroscopy and to not repeat mistakes made in this development process.

Threshold Effects In Strong-Field Ionization: Energy Shifts And Rydberg Structures, Katarzyna Krajewska, Ilya I. Fabrikant, Anthony F. Starace

Anthony F. Starace Publications

The behavior of strong-field ionization rates of neutral atoms in the vicinity ofmultiphoton ionization thresholds is analyzed using formal collision theory.Our approach,which accounts nonperturbatively for effects of an intense laser field, shows that the ionization rates have a nearly constant behavior below and above each multiphoton threshold and that between such thresholds there are an apparently finite number of rapid oscillations due to resonances with laser-field-modified Rydberg states. This pattern is typical for any atomic target, as we illustrate specifically for hydrogen and neon atoms. The flat behavior of the ionization yield near multiphoton thresholds gives the appearance of an …

Black Holes In The Conical Ensemble, Robert A. Mcnees Iv, Daniel Grumiller

Physics: Faculty Publications and Other Works

We consider black holes in an “unsuitable box”: a finite cavity coupled to a thermal reservoir at a temperature different than the black hole’s Hawking temperature. These black holes are described by metrics that are continuous but not differentiable due to a conical singularity at the horizon. We include them in the Euclidean path integral sum over configurations, and analyze the effect this has on black hole thermodynamics in the canonical ensemble. Black holes with a small deficit (or surplus) angle may have a smaller internal energy or larger density of states than the nearby smooth black hole, but they …

Ads/Cft In String Theory And M-Theory, Daniel R. Gulotta '03

Doctoral Dissertations

The AdS/CFT correspondence is a powerful tool that can help shed light on the relationship between geometry and field theory.

The first part of this thesis will focus on the construction of theories dual to Type IIB string theory on AdS₅ x Y⁵, where Y⁵ is a toric Sasaki-Einstein manifold. This thesis will introduce a consistency condition called "proper ordering" and demonstrate that it is equivalent to several other previously known consistency conditions. It will then give an efficient algorithm that produces a consistent field theory for any toric Sasaki-Einstein Y⁵.

The second part …

Black Hole Thermalization, D0 Brane Dynamics, And Emergent Spacetime, Paul L. Riggins '12, Vatche Sahakian

All HMC Faculty Publications and Research

When matter falls past the horizon of a large black hole, the expectation from string theory is that the configuration thermalizes and the information in the probe is rather quickly scrambled away. The traditional view of a classical unique spacetime near a black hole horizon conflicts with this picture. The question then arises as to what spacetime does the probe actually see as it crosses a horizon, and how does the background geometry imprint its signature onto the thermal properties of the probe. In this work, we explore these questions through an extensive series of numerical simulations of D0 branes. …

Gain Of A Single Gas Electron Multiplier, Mythra Varun Nemallapudi

Graduate Theses and Dissertations

Gas Electron Multiplier (GEM) is a gaseous detector used in particle detection and is known for its high rate capability. Ever since its invention in 1997, GEM was applied in many areas and recently has been proposed to be installed in the CMS high η regions for upgrade at LHC, CERN. A complete understanding of the working and gain behaviour does not exist. GEM gain is influenced by charging up and this has been variedly interpreted in literature lacking consensus. I have attempted in this work through simulations and measurements to achieve a better understanding of single GEM gain and …

A Homogeneous Solution Of The Einstein-Maxwell Equations, Charles G. Torre

Research Vignettes

We exhibit and analyze a homogeneous spacetime whose source is a pure radiation electromagnetic field [1]. It was previously believed that this spacetime is the sole example of a homogeneous pure radiation solution of the Einstein equations which admits no electromagnetic field (see [2] and references therein). Here we correct this error in the literature by explicitly displaying the electromagnetic source. This result implies that all homogeneous pure radiation spacetimes satisfy the Einstein-Maxwell equations.

PDF and Maple worksheets can be downloaded from the links below.

How To Create A Lie Algebra, Ian M. Anderson

How to... in 10 minutes or less

We show how to create a Lie algebra in Maple using three of the most common approaches: matrices, vector fields and structure equations. PDF and Maple worksheets can be downloaded from the links below.

The Study Of Pt Dependence Of Dijet Azimuthal Decorrelations In Proton-Proton Collision At Center Of Mass Energy = 7 Tev, Ramasudhakar Dhullipudi

Doctoral Dissertations

The transverse momentum (pT) dependence of azimuthal decorrelations in dijet events is studied with data collected, at an integrated luminosity of [special characters omitted] dt = (36 ± 4) pb−1, from collisions between protons at a center of mass energy of [special characters omitted] = 7 TeV using the ATLAS detector at the Large Hadron Collider. The results of the analysis of jets in a central rapidity of |y| < 0.8 and pT in the range 60 GeV < pT < 1200 GeV are presented. A new observable RΔ&phis;, defined as the fraction of the total dijet cross section corresponding to a particular range of …

Study Of Jet Transverse Momentum And Jet Rapidity Dependence Of Dijet Azimuthal Decorrelations With The Dø Detector, Kiran Chakravarthula

Doctoral Dissertations

In a collision experiment involving highly energetic particles such as hadrons, processes at high momentum transfers can provide information useful for many studies involving Quantum Chromodynamics (QCD). One way of analyzing these interactions is through angular distributions. In hadron-hadron collisions, the angular distribution between the two leading jets with the largest transverse momentum (pT) is affected by the production of additional jets. While soft radiation causes small differences in the azimuthal angular distribution of the two leading jets produced in a collision event, additional hard jets produced in the event have more pronounced influence on the distribution of …

Event Shapes In Proton-Proton Collisions At Center Of Mass Energy = 1.96 Tev, Scott Atkins

Doctoral Dissertations

This dissertation presents the analysis of nine different event shapes measured in high energy pp¯ collisions. An event shape can be defined as an event-based quantity that measures how the final energies are distributed in the final event. This analysis will test strong interactions as described by Quantum Chromodynamics (QCD), through their implementation in different Monte Carlo-based models. Each of the event shapes provides information about the flow of energy in QCD events and about the hadronic final states that occur in pp¯ particle collisions, thus allowing the study of the dynamics of QCD multijet events. Any deviation of an …

The Search For Charged Massive Supersymmetric Particles At The Lhc, Aleksey Pavlov

Physics

Charged Massive Particles (CHAMPs) are predicted in the Supersymmetry (SUSY) extension of the Standard Model though they have never been ob- served. We look for CHAMPs in the ALICE Detector at the Large Hadron Collider at CERN. While the main purpose of ALICE is to study Quark- Gluon Plasma, we take advantage of the tracking and time of flight capabilities of several sub-detectors in ALICE to look for signs of CHAMPs. These elusive particles are characterized by their slow velocity, high transverse momentum and therefore heavy mass. Our research found a small handful of candidates among a large sample size …

Study Of The Structure Of 9C Via Single Neutron Transfer, Scott T. Marley

Dissertations

This thesis describes a study of the nucleus ⁹C, produced in the single-neutron transfer reaction d(¹⁰C, t) ⁹C using a radioactive ¹⁰C beam. The structure of the neutron-deficient nucleus ⁹C is poorly known. Only a few excited states have been observed and no information exists of their single-particle characteristics. The measured ground-state magnetic dipole moment of ⁹C is anomalously small and could imply large contributions from sd-shell orbitals in the ground-state wave function. The positions of the ⁹C excited states and their single-particle properties are vital to furthering the …

Light Vs. Quantum Gravity, Irving Martinez^*

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Equation Of State Of A Strongly Coupled Fermion System, Jason P. Keith^, Efrain J. Ferrer*

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Single And Double Spin Asymmetries For Pion Electro-Production From The Deuteron In The Resonance Region, Sharon L. Careccia

Physics Theses & Dissertations

The single and double spin asymmetries A_t and A_et have been measured in π^- electro-production off the deuteron using a longitudinally polarized electron beam and a polarized ND₃ target. The electron beam was polarized using a strained GaAs cathode and the target was polarized using Dynamic Nuclear Polarization. The data were collected at beam energies of 1.6, 1.7, 2.5 and 4.2 GeV in Hall B at Jefferson Lab in the spring of 2001. The final state particles were detected in the CEBAF Large Acceptance Spectrometer (CLAS). The d(e,e'π-p)p exclusive channel was identified using the missing mass …

Photon Impact Factor And 𝑘T Factorization In The Next-To-Leading Order, Ian Balitsky

Physics Faculty Publications

The photon impact factor for the BFKL pomeron is calculated in the next-to-leading order (NLO) approximation using the operator expansion in Wilson lines. The result is represented as a NLO k_T-factorization formula for the structure functions of small-x deep inelastic scattering.

Evidence For The Onset Of Color Transparency In Ρ0 Electroproduction Off Nuclei, L. El Fassi, L. Zana, H. Hafidi, M. Holtrop, B. Mustapha, W. K. Brooks, H. Hakobyan, Z. Zheng, K. P. Adhikari, D. Adikaram, M. J. Amaryan, H. Baghdasaryan, S. Bültmann, G. E. Dodge, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, L. B. Weinstein

Physics Faculty Publications

We have measured the nuclear transparency of the incoherent diffractive A( e , e ′ ρ⁰ ) process in ¹²C and ⁵⁶Fe targets relative to ²H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced ρ⁰ ʼs on a nucleus relative to deuterium, which is sensitive to ρA interaction, was studied as function of the coherence length (lc), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared (Q²). While the transparency for both ¹²C and ⁵⁶Fe …

Measurement Of Exclusive Πº Electroproduction Structure Functions And Their Relationship To Transverse Generalized Parton Distributions, Clas Collaboration, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, S. Koirala, S. E. Kuhn, M. Mayer, L. B. Weinstein, I. Bedlinsky, V. Kubarovsky

Physics Faculty Publications

Exclusive π⁰ electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in Q², x_B , t , and ϕπ , in the Q² range from 1.0 to 4.6  GeV² , −t up to 2  GeV² , and x_B from 0.1 to 0.58. Structure functions σ_T+ϵσ_L , σ_TT , and σ_LT were extracted as functions of t for each of 17 combinations of Q² and x_B . …

Measurement Of The Generalized Form Factors Near Threshold Via ˠ*P→Nπ+ At High Q², Clas Collaboration, K. Park, R. W. Gothe, K. P. Adhikari, D. Adikaram, R. P. Bennett, C. E. Hyde, A. Klein, S. E. Kuhn, H. Seraydaryan

Physics Faculty Publications

We report on the first measurement of the F₂ structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲ 100  MeV/c and their angles to ≳ 100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The Fⁿ₂ data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65 < Q² 2, with uncertainties from nuclear corrections estimated to be less …