Elementary Particles and Fields and String Theory Commons^™

Gauge Transformations Of The Biconformal Connection, James Thomas Wheeler

All Physics Faculty Publications

We study the changes of the biconformal gauge fields under the local rotational and dilatational gauge transformations.

Rainich-Type Conditions For Perfect Fluid Spacetimes, Dionisios Krongos, Charles G. Torre

Research Vignettes

In this worksheet we describe and illustrate a relatively simple set of new Rainich-type conditions on an n-dimensional spacetime which are necessary and sufficient for it to define a perfect fluid solution of the Einstein field equations. Procedures are provided which implement these Rainich-type conditions and which reconstruct the perfect fluid from the metric. These results provide an example of the idea of geometrization of matter fields in general relativity, which is a purely geometrical characterization of matter fields via the Einstein field equations.

Supergravity Backgrounds For Deformations Of Adsn×Sn Supercoset String Models, Oleg Lunin, Radu Roiban, Arkady Tseytlin

Physics Faculty Scholarship

We consider type IIB supergravity backgrounds corresponding to the deformed AdS_n x S^n supercoset string models of the type constructed in arXiv:1309.5850 which depend on one deformation parameter k. In AdS_2 x S^2 case we find that the deformed metric can be extended to a full supergravity solution with non-trivial dilaton, RR scalar and RR 5-form strength. The solution depends on a free parameter (called a) that should be chosen as a particular function of k to correspond to the deformed supercoset model. In AdS_3 x S^3 case the full solution supported by the dilaton, RR scalar and RR 3-form …

Nonlinear Dichroism In Back-To-Back Double Ionization Of He By An Intense Elliptically Polarized Few-Cycle Extreme Ultraviolet Pulse, Jean Marcel Ngoko Djiokap, N. L. Manakov, A. V. Meremianin, S. X. Hu, L. B. Madsen, Anthony F. Starace

Anthony F. Starace Publications

Control of double ionization of He by means of the polarization and carrier-envelope phase (CEP) of an intense, few-cycle extreme ultraviolet (XUV) pulse is demonstrated numerically by solving the six-dimensional two-electron, time-dependent Schrödinger equation for He interacting with an elliptically polarized XUV pulse. Guided by perturbation theory (PT), we predict the existence of a nonlinear dichroic effect (∝ I^3/2) that is sensitive to the CEP, ellipticity, peak intensity I, and temporal duration of the pulse. This dichroic effect (i.e., the difference of the two-electron angular distributions for opposite helicities of the ionizing XUV pulse) originates from interference of …

Physics: Rethinking The Foundations, Kevin H. Knuth

Physics Faculty Scholarship

Physics is traditionally conceived of as a set of laws that universally governs the behavior of physical systems. These laws, however they are decreed, are believed to govern the behavior of not only everything in the universe, but the form of the universe itself. However, this traditional concept of physics as a universal governance is at odds with our modern theories of quantum mechanics and relativity, which place the observer and information in a central role. In this talk, I aim to rethink the foundations and attempt to build physics from the bottom up based on a very simple foundational …

Studies Of Angular Correlations Of Jets With The Atlas Detector, Rajivalochan Subramaniam

Doctoral Dissertations

The strong force is one of the four fundamental forces and its strength is given by the coupling constant αs. The theory that describes the strong interaction is Quantum Chromodynamics (QCD) and it explains the interactions between quarks and gluons. The strong coupling constant is the only free parameter in the QCD Lagrangian if the quark masses are fixed. Determinations of αs provide direct tests of perturbative QCD calculations. The collimated sprays of particles originating from the quark and gluon interactions are called jets. The ratio of jet cross sections are sensitive to α s and are …

Beam-Induced Radiation Heating On The Superconducting Undulator At The Advanced Photon Source, Laura Elizabeth Boon

Open Access Dissertations

In January 2013 the Advanced Photon Source (APS), a 7 GeV synchrotron X-ray source, commissioned a Superconducting Undulator (SCU). The superconducting magnet is thermally isolated from the beam vacuum chamber, which absorbs the beam-induced heating. Previous beam induced heat load studies at other laboratories had not included a robust calculation of radiation heating from the upstream dipole magnet. The mitigation of the radiation heating mechanism, and production of photoelectrons to seed an electron cloud was studied for this thesis. ^ An analytical model was developed to predict the radiation heat load on the SCU chamber. This model was benchmarked with …

Effects Of Energetic Irradiation On Materials And Devices Based On Graphene And Topological Insulators, Isaac Childres

Open Access Dissertations

This report focuses on the optical and electronic properties of graphene and topological insulators and how these Dirac fermion systems interact with energetic irradiation. We first present data exploring the effects of electron-beam and oxygen plasma induced disorder on the electronic properties and Raman spectra of graphene. These initial investigations were important for relating Raman peak intensities and weak localization features to each other and to an average disorder length in graphene, L_D. ^ We then integrate gate-effect measurements into the Raman spectroscopy study to fully explore the relationships between carrier density, disorder and Raman spectrum signatures. We …

Investigation And Optimization Of A New Compact Superconducting Cavity For Deflecting And Crabbing Applications, Subashini Uddika De Silva

Physics Theses & Dissertations

Deflecting and crabbing structures have many applications in current accelerator systems. The primary use of a deflecting cavity is to separate a single beam into multiple beams. A crabbing cavity enables the head-on collision at the interaction point in particle colliders in order to increase the luminosity. The early uses of the deflecting structures have been in the early 1960s: these structures were disk loaded structures operating at room temperature. The crabbing structure which was installed at the NEK electron-positron collider was the first and only operational superconducting cavity of that kind. The most common design of superconducting deflecting and …

Search For New Physical Phenomena Via Displaced Muon Signatures With The Cms Detector At The Lhc, Melih Solmaz

Open Access Theses

The first search at the LHC for long-lived neutral particles decaying to pairs of muons by using only the muon chambers is presented. Events were collected by the CMS detector during pp collisions at √s = 8 TeV and selected from data samples corresponding to 20.5 fb^-1 of integrated luminosity. No background events are expected after the full analysis selection. Expected upper limits are derived for a model which predicts a heavy scalar decaying to two long-lived particles, each of which can decay to muon pairs. Combined expected upper limits with an analysis utilizing the CMS silicon tracker …

Semi-Inclusive Charged-Current Neutrino-Nucleus Reactions, O. Moreno, T. W. Donnelly, J. W. Van Orden, W. P. Ford

Physics Faculty Publications

The general, universal formalism for semi-inclusive charged-current (anti) neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized, and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case …

Perturbative Unitarity Constraints On A Supersymmetric Higgs Portal, Kassahun Betre, Sonia Hedri, Devin Walker

Faculty Publications

We place perturbative unitarity constraints on both the dimensionful and dimensionless couplings in the Next-to-Minimal Supersymmetric Standard Model Higgs Sector. These constraints, plus the requirement that the singlino and/or Higgsino constitutes at least part of the observed dark matter relic abundance, generate upper bounds on the Higgs and neutralino/chargino mass spectrum. We obtain an upper bound of 12 TeV for the charginos and neutralinos and 20 TeV for the heavy Higgses outside defined fine-tuned regions. By using the NMSSM as a template, we describe a method which replaces naturalness arguments with more rigorous perturbative unitarity arguments to get a better …

Analytic Evolution Of Singular Distribution Amplitudes In Qcd, Asli Tandogan

Physics Theses & Dissertations

Distribution amplitudes (DAs) are the basic functions that contain information about the quark momentum. DAs are necessary to describe hard exclusive processes in quantum chromodynamics. We describe a method of analytic evolution of DAs that have singularities such as nonzero values at the end points of the support region, jumps at some points inside the support region and cusps. We illustrate the method by applying it to the evolution of a flat (constant) DA, antisymmetric flat DA, and then use the method for evolution of the two-photon generalized distribution amplitude. Our approach to DA evolution has advantages over the standard …

Yang-Mills Theories As Deformations Of Massive Integrable Models, Axel Cortes Cubero

Dissertations, Theses, and Capstone Projects

Yang Mills theory in 2+1 dimensions can be expressed as an array of coupled (1+1)-dimensional principal chiral sigma models. The SU(N) principal chiral sigma model in 1+1 dimensions is integrable, asymptotically free and has massive excitations. We calculate all the form factors and two- point correlation functions of the Noether current and energy-momentum tensor, in

't Hooft's large-N limit (some form factors can be found even at finite N). We use these new form factors to calculate physical quantities in (2+1)-dimensional Yang-Mills theory, generalizing previous SU(2) by P. Orland to SU(N). The anisotropic gauge theory is related to standard isotropic …

Initial Conditions In High-Energy Collisions, Elena Petreska

Dissertations, Theses, and Capstone Projects

This thesis is focused on the initial stages of high-energy collisions in the saturation regime. We start by extending the McLerran-Venugopalan distribution of color sources in the initial wave-function of nuclei in heavy-ion collisions. We derive a fourth-order operator in the action and discuss its relevance for the description of color charge distributions in protons in high-energy experiments. We calculate the dipole scattering amplitude in proton-proton collisions with the quartic action and find an agreement with experimental data. We also obtain a modification to the fluctuation parameter of the negative binomial distribution of particle multiplicities in proton-proton experiments. The result …

Direct Measurements Of Two Photon Exchange On Lepton-Proton Elastic Scattering Using Simultaneous Electron-Positron Beams In Clas, Dasuni Kalhari Adikaram

Physics Theses & Dissertations

The electric (GE) and magnetic ( GM) form factors of the proton are fundamental observables which characterize its charge and magnetization distributions. There are two methods to measure the proton form factors: the Rosenbluth separation method and the polarization transfer technique. However, the ratio of the electric and magnetic form factors measured by those methods significantly disagree at momentum transfer Q² > 1 GeV². The most likely explanation of this discrepancy is the inclusion of two-photon exchange (TPE) amplitude contributions to the elastic electron-proton cross section which significantly changes the extraction of GE from the …

Resonant Electron-Atom Bremsstrahlung In An Intense Laser Field, A. N. Zheltukhin, A. V. Flegel, M. V. Frolov, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

We analyze a resonant mechanism for spontaneous laser-assisted electron bremsstrahlung (BrS) involving the resonant transition (via either laser-assisted electron-ion recombination or electron-atom attachment) into a laser-dressed intermediate quasibound state (corresponding, respectively, to either a field-free neutral atom or a negative-ion bound state) accompanied by ionization or detachment of this state by the laser field. This mechanism leads to resonant enhancement (by orders of magnitude) of the BrS spectral density for emitted photon energies corresponding to those for laser-assisted recombination or attachment. We present an accurate parametrization of the resonant BrS amplitude in terms of the amplitudes for nonresonant BrS, for …

Gauge/ Gravity Correspondence, Bulk Locality And Quantum Black Holes, Debajyoti Sarkar

Dissertations, Theses, and Capstone Projects

The aim of this dissertation is threefold. We begin by the study of two parallel ideal cosmic strings in the presence of non-minimal scalar fields and spin- 1 gauge fields. We show that the contributions of the non-minimal term on the interaction energy between the strings are similar to that of the gauge field for a particular value of non-minimal coupling parameter. In this context we clarify some of the issues that arise when comparing the renormalization of black hole entropy and entanglement entropy using the replica trick.

In the second part of the dissertation we study the process of …

Search For Contact Interactions Using The Dimuon Mass Spectrum In P-P Collisions At Sqrt(S) = 8 Tev At Cms, Chamath Kottachchi

Wayne State University Dissertations

The mass hierarchy problem associated with the standard model suggests that there might be more fundamental particles in nature. If quarks and leptons have substructures, known as preons, the manifestation of compositeness can be a four-fermion contact interaction. The experimental signal for contact interactions is a non-resonant enhancement of the number of events in the high-mass region of the dimuon mass spectrum. This dissertation describes a detailed search strategy for contact interactions using the Compact Muon Solenoid experiment. The dimuon mass spectrum above 300 GeV has been studied using the data collected in 2012 at sqrt(s) = 8 TeV corresponding …

Weak Decay Studies From An Effective Theory Standpoint, Aditya Yechan Gunja

Wayne State University Dissertations

In this doctoral dissertation I discuss the phenomenology of some weak interaction decays using a model independent approach by employing effective field theories. I discuss the soft photon contribution and background effect to the rare dimuonic decay of the neutral B meson. I also study some radiative exclusive W boson decays in the standard model in the context of pQCD and SCET. Additionally I invoke leptonic decays of charged mesons to constrain two general models of light dark matter.

Algebraic Formulation Of Hadronic Supersymmetry Based On Octonions: New Mass Formulas And Further Applications, Sultan Catto, Yasemin Gürcan, Amish Khalfan, Levent Kurt

Publications and Research

A special treatment based on the highest division algebra, that of octonions and their split algebraic formulation is developed for the description of diquark states made up of two quark pairs. We describe symmetry properties of mesons and baryons through such formulation and derive mass formulae relating π, ρ, N and Δ trajectories showing an incredible agreement with experiments. We also comment on formation of diquark-antidiquark as well as pentaquark states and point the way toward applications into multiquark formulations expected to be seen at upcoming CERN experiments. A discussion on relationship of our work to flux bag models, string …

Large-Angle Beamstrahlung: Simulation And Diagnostics, Ryan Stephen Gillard

Wayne State University Dissertations

LARGE-ANGLE BEAMSTRAHLUNG: SIMULATION AND DIAGNOSTICS

by

RYAN S. GILLARD

May 2014

Advisor: Dr. Giovanni Bonvicini

Major: Physics

Degree: Doctor of Philosophy

Luminosity is paramount in high energy physics research, therefore it is critical to optimize it. Particle beams are complex and orbit in a complicated fashion therefore they don't always collide as intended thus reducing our chance of discovery. Simulations and calculations of the beam-beam radiation or beamstrahlung can provide crucial insight into the collision geometry. Combined with an optics box that can collect and analyze this radiation, this could be an extremely valuable tool leading to correction of the …

Probing New Physics Through Third Generation Leptons, Preet Sharma

Electronic Theses and Dissertations

This dissertation is a study of beyond standard model physics or new physics. The third generation charged lepton -the τ -is an excellent probe of new physics (NP) because of it being the heaviest lepton. As the heaviest lepton, it has the largest coupling ( among the leptons) to the Higgs boson in the Standard Model (SM). New physics contributions to the tau-neutrino nucleon scattering were considered. Charged Higgs and W' effects to the deep inelastic scattering ντ ( [special character omitted]τ) + N → τ− (τ+) + X in the neutrino-nucleon interactions has been studied. The neutrino detection process …

Determination Of Jet Transport Parameters And Their Temperature Dependence In Heavy-Ion Collisions, Karen Marie Burke

Wayne State University Theses

In the continuing effort to describe properties of the quark-gluon plasma, energy loss is studied through leading order higher twist calculations of high transverse momentum single hadron suppression. Input of several values for the jet transport parameter q ̂ were used at pT ranges of ~5-20 GeV at RHIC and ~10-100 GeV at LHC, with collision centrality of 0-5%. The results of the calculations are then compiled and compared with experimental data to determine the best fit value for q ̂.

Gpu Accelerated Long-Term Simulations Of Beam-Beam Effects In Colliders, B. Terzić, V. Morozov, Y. Roblin, F. Lin, H. Zhang, M. Aturban, D. Ranjan, M. Zubair

Computer Science Faculty Publications

We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.

Observation Of D⁰ Meson Nuclear Modifications In Au + Au Collisions At √SNn = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, M. Zyzak, Et Al., Star Collaboration

Physics Faculty Publications

We report the first measurement of charmed-hadron (D⁰) production via the hadronic decay channel (D⁰→K⁻+π⁺) in Au+Au collisions at √s_NN=200  GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N_bin, from p+p to central Au+Au collisions. The D⁰ meson yields in central Au+Au collisions are strongly suppressed compared to those in p+p scaled by N_bin, for transverse momenta p_T > 3  GeV/c, demonstrating significant energy loss of charm quarks in the hot …

Beam-Energy Dependence Of Charge Separation Along The Magnetic Field In Au + Au Collisions At Rhic, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, M. Zyzak, Et Al., Star Collaboration

Physics Faculty Publications

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with …

Nuclear Electromagnetic Processes In Cheft, L. Girlanda, L. E. Marcucci, S. Pastore, M. Piarulli, R. Schiavilla, M. Viviani

Physics Faculty Publications

We review our recent work on the derivation of the nuclear electromagnetic charge and current operators in chiral perturbation theory, based on time-ordered perturbation theory. We then discuss the strategies for fixing the relevant low-energy constants, and compare the resulting predictions for the electric and magnetic form factors of the deuteron and trinucleons with experimental data, using as input accurate nuclear wave functions derived with realistic potentials.

Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized He-3 Target, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, M. Canan

Physics Faculty Publications

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of0.1 < x_bj < 0.4for K⁺ and K⁻ production. While the Collins and Sivers moments for K⁺ are consistent with zero within the experimental uncertainties, both moments for K⁻ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While …

Precision Measurement Of The Neutron Twist-3 Matrix Element D(2)(N): Probing Color Forces, M. Posik, D. Flay, D. S. Parrno, K. Allada, W. Armstrong, F. Benmokhtar, M. Canan, L. El Fassi, S. Golge, C. Hyde

Physics Faculty Publications

Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25 ≤ x ≤ 0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized ³He target. In this dedicated experiment, the spin structure function g(2)(3He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at < Q²> of 3.21 and 4.32 GeV²/c², with an absolute precision of about 10^-5. Our results are found to be in agreement …