Elementary Particles and Fields and String Theory Commons^™

Unification Of Gravity And Quantum Theory, Adam Daniels

Faculty-Sponsored Student Research & Capstones

An overview of the four fundamental forces of physics as described by the Standard Model (SM) and prevalent unifying theories beyond it is provided. Background knowledge of the particles governing the fundamental forces is provided, as it will be useful in understanding the way in which the unification efforts of particle physics has evolved, either from the SM, or apart from it. It is shown that efforts to provide a quantum theory of gravity have allowed supersymmetry (SUSY) and M-Theory to become two of the prevailing theories for unifying gravity with the remaining non-gravitational forces.

Isoscalar 𝜋𝜋 Scattering And The Σ Meson Resonance From Qcd, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, David J. Wilson

Physics Faculty Publications

We present for the first time a determination of the energy dependence of the isoscalar ππ elastic scattering phase shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are computed including all required quark propagation diagrams, and from these the discrete spectrum of states in the finite volume defined by the lattice boundary is extracted. From the volume dependence of the spectrum, we obtain the S-wave phase shift up to the KK¯ threshold. Calculations are performed at two values of the u, d quark mass corresponding to m_π=236,391  MeV, and the resulting amplitudes …

Relating The Finite-Volume Spectrum And The Two And Three-Particle S Matrix For Relativistic Systems Of Identical Scalar Particles, Raúl Briceño, Maxwell T. Hansen, Stephen R. Sharpe

Physics Faculty Publications

Working in relativistic quantum field theory, we derive the quantization condition satisfied by coupled two- and three-particle systems of identical scalar particles confined to a cubic spatial volume with periodicity L. This gives the relation between the finite-volume spectrum and the infinite-volume 2 → 2, 2 → 3, and 3 → 3 scattering amplitudes for such theories. The result holds for relativistic systems composed of scalar particles with nonzero mass m, whose center of mass energy lies below the four-particle threshold, and for which the two-particle K matrix has no singularities below the three-particle threshold. The quantization condition is exact …

Role Of The Euclidean Signature In Lattice Calculations Of Quasidistributions And Other Nonlocal Matrix Elements, Raúl A. Briceño, Maxwell T. Hansen, Christopher J. Monahan

Physics Faculty Publications

Lattice quantum chromodynamics (QCD) provides the only known systematic, nonperturbative method for first-principles calculations of nucleon structure. However, for quantities such as light-front parton distribution functions (PDFs) and generalized parton distributions (GPDs), the restriction to Euclidean time prevents direct calculation of the desired observable. Recently, progress has been made in relating these quantities to matrix elements of spatially nonlocal, zero-time operators, referred to as quasidistributions. Still, even for these time-independent matrix elements, potential subtleties have been identified in the role of the Euclidean signature. In this work, we investigate the analytic behavior of spatially nonlocal correlation functions and demonstrate that …

Some 2-Categorical Aspects In Physics, Arthur Parzygnat

Dissertations, Theses, and Capstone Projects

2-categories provide a useful transition point between ordinary category theory and infinity-category theory where one can perform concrete computations for applications in physics and at the same time provide rigorous formalism for mathematical structures appearing in physics. We survey three such broad instances. First, we describe two-dimensional algebra as a means of constructing non-abelian parallel transport along surfaces which can be used to describe strings charged under non-abelian gauge groups in string theory. Second, we formalize the notion of convex and cone categories, provide a preliminary categorical definition of entropy, and exhibit several examples. Thirdly, we provide a universal description …

Ultracold Quantum Scattering In The Presence Of Synthetic Spin-Orbit Coupling, Su-Ju Wang

Open Access Dissertations

Two-body scattering constitutes one of the most fundamental processes in various physical systems ranging from ultracold dilute quantum gases to energetic quark- gluon plasmas. In this dissertation, we study the low-energy atomic collision physics in the presence of synthetic gauge fields, which are generated by atom-light interaction. One category of synthetic gauge fields is the artificial spin-orbit coupling. We discuss three different aspects in scattering theory: ultracold collision, scattering resonance, and bound state formation from a few-body perspective when the atomic spin states are coupled with their center-of-mass motion. The understanding of the spin-orbit effects on the modification of the …

Event Generator Tunes Obtained From Underlying Event And Multiparton Scattering Measurements, Cms Collaboration, Ekaterina Cms Avdeeva, Kenneth A. Bloom, S. Bose, Daniel Claes, Aaron Dominguez, Caleb Fangmeier, Rebeca Gonzalez Suarez, Rami Kamalieddin, J. Keller, D. Knowlton, Ilya Kravchenko, F. Meier, Jose Monroy, F. Ratnikov, J. E. Siado, Gregory Snow

Kenneth Bloom Publications

New sets of parameters (“tunes”) for the underlying-event (UE) modelling of the PYTHIA8, PYTHIA6 and HERWIG++ MonteCarlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton–proton (pp) data at √s = 7 TeV and to UE proton–antiproton (pp) data from the CDF experiment at lower √s, are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton–proton collisions at 13 TeV. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive …

Measurement Of The Differential Cross Section And Charge Asymmetry For Inclusive Pp → W± + X Production At √S = 8 Tev, Ekaterina Avdeeva, Rachel Bartek, Kenneth A. Bloom, Suvadeep Bose, Daniel R. Claes, Aaron Dominguez, Caleb Fangmeier, Rebeca Gonzalez Suarez, Rami Kamalieddin, Daniel Knowlton, Ilya Kravchenko, Jose Monroy, F. Meier, F. Ratnikov, J. E. Siado, Gregory Snow, B. Stieger, Cms Collaboration

Department of Physics and Astronomy: Faculty Publications

The differential cross section and charge asymmetry for inclusive pp → W^± + X → μ^±ν + X production at √s = 8 TeV are measured as a function of muon pseudorapidity. The data sample corresponds to an integrated luminosity of 18.8 fb⁻¹ recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10⁻³ to 10⁻¹.

Rapidity Factorization And Evolution Of Gluon Tmds, Ian Balitsky

Physics Faculty Publications

I discuss how the rapidity evolution of gluon transverse momentum dependent distribution changes from nonlinear evolution at small x « 1 to linear evolution at moderate x ∼ 1.

Relativistic, Model-Independent, Multichannel 2 → 2 Transition Amplitudes In A Finite Volume, Raúl A. Briceño, Maxwell T. Hansen

Physics Faculty Publications

We derive formalism for determining 2+𝓙 → 2 infinite-volume transition amplitudes from finite-volume matrix elements. Specifically, we present a relativistic, model-independent relation between finite-volume matrix elements of external currents and the physically observable infinite-volume matrix elements involving two-particle asymptotic states. The result presented holds for states composed of two scalar bosons. These can be identical or nonidentical and, in the latter case, can be either degenerate or nondegenerate. We further accommodate any number of strongly coupled two-scalar channels. This formalism will, for example, allow future lattice QCD calculations of the ρ-meson form factor, in which the unstable nature of …

𝜋𝜋 → 𝜋𝛾* Amplitude And The Resonant 𝜌 → 𝜋𝛾* Transition From Lattice Qcd, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, Christian J. Shultz, Christopher E. Thomas, David J. Wilson

Physics Faculty Publications

We present a determination of the P-wave 𝜋𝜋 → 𝜋𝛾⋆ transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite volume are extracted from three-point correlation functions, and from these we determine the infinite-volume amplitude using a generalization of the Lellouch-Lüscher formalism. We determine the amplitude for a range of discrete values of the 𝜋𝜋 energy and virtuality of the photon and observe the expected dynamical enhancement due to the ρ resonance. Describing the energy dependence of the amplitude, we are able to analytically continue into the complex energy plane and from the residue …

Relating Transverse-Momentum-Dependent And Collinear Factorization Theorems In A Generalized Formalism, J. Collins, L. Gamberg, A. Prokudin, T. C. Rogers, N. Sato, B. Wang

Physics Faculty Publications

We construct an improved implementation for combining transverse-momentum-dependent (TMD) factorization and collinear factorization. TMD factorization is suitable for low transverse momentum physics, while collinear factorization is suitable for high transverse momenta and for a cross section integrated over transverse momentum. The result is a modified version of the standard 𝑊 + 𝑌 prescription traditionally used in the Collins-Soper-Sterman (CSS) formalism and related approaches. We further argue that questions regarding the shape and 𝑄 dependence of the cross sections at lower 𝑄 are largely governed by the matching to the 𝑌 term.

Resonant 𝜋⁺𝜸 → 𝜋⁺𝜋⁰ Amplitude From Quantum Chromodynamics, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, Christian J. Shultz, Christopher E. Thomas, David J. Wilson

Physics Faculty Publications

We present the first ab initio calculation of a radiative transition of a hadronic resonance within quantum chromodynamics (QCD). We compute the amplitude for 𝜋𝜋→𝜋𝜸^⋆, as a function of the energy of the 𝜋𝜋 pair and the virtuality of the photon, in the kinematic regime where 𝜋𝜋 couples strongly to the unstable ρ resonance. This exploratory calculation is performed using a lattice discretization of QCD with quark masses corresponding to m_π ≈ 400  MeV. We obtain a description of the energy dependence of the transition amplitude, constrained at 48 kinematic points, that we can analytically continue …

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 …

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 …

Φ-Meson Photoproduction On Hydrogen In The Neutral Decay Mode, H. Seraydaryan, M. J. Amaryan, G. Gavalian, L. Weinstein, K. P. Adhikari, D. Adikaram, R. P. Bennett, S. Bültmann, N. Guler, C. E. Hyde, S. Koirala, S. E. Kuhn, L. B. Weinstein

Physics Faculty Publications

We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp→pϕ(K_SK_L) . The experiment was performed with a tagged photon beam of energy 1.6 ≤ E_γ ≤ 3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of K_S in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp→pK_SX to be K_L. …

Measurement Of The Structure Function Of The Nearly Free Neutron Using Spectator Tagging In Inelastic ²H(E,E'Pˢ) X Scattering With Clas, S. Tkachenko, S. E. Kuhn, J. Zhang, K. P. Adhikari, M. J. Amaryan, A. Klein, S. Koirala, M. Mayer, L. Zana, Clas Collaboration

Physics Faculty Publications

Background: Much less is known about neutron structure than that of the proton due to the absence of free neutron targets. Neutron information is usually extracted from data on nuclear targets such as deuterium, requiring corrections for nuclear binding and nucleon off-shell effects. These corrections are model dependent and have significant uncertainties, especially for large values of the Bjorken scaling variable x . As a consequence, the same data can lead to different conclusions, for example, about the behavior of the d quark distribution in the proton at large x .

Purpose: The Barely Off-shell Nucleon Structure experiment at Jefferson …

Induced Polarization Of Λ1116 In Kaon Electroproduction, Clas Collaboration, D. Adikaram, M. J. Amaryan, L. El Fassi, S. Koirala, S. E. Kuhn, M. Mayer

Physics Faculty Publications

We have measured. the induced polarization of the Λ (1116) in the reaction ep →e′K⁺Λ , detecting the scattered e′ and K⁺ in the final state along with the proton from the decay Λ → pπ⁻ . The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy W (1.6≤ W ≤ 2.7 GeV) and covered the full range of the kaon production angle at an average momentum transfer Q² = 1.90GeV² . In this experiment a 5.50-GeV electron beam was incident upon …

High Precision Determination Of The Q² Evolution Of The Bjorken Sum, A. Deur, Y. Prok, V. Burkert, D. Crabb, F. X. Girod, K. A. Griffioen, N. Guler, S. E. Kuhn, N. Kvaltine

Physics Faculty Publications

We present a significantly improved determination of the Bjorken sum for 0.6 ≤ Q² ≤ 4.8 GeV² using precise new g^p₁ and g^d₁ data taken with the CLAS detector at Jefferson Lab. A higher-twist analysis of the Q² dependence of the Bjorken sum yields the twist-4 coefficient f ^p-n₂= -0.064 ± 0.009 ± ^0.032 _0.036. This leads to the color polarizabilities χ ^p-n _E= -0.032 ± 0.024 and χ^p-n_B= 0.032 ± 0.013. The strong force coupling is determined to be α ^MS_S (M²_{Z …}

Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction 𝛾p → Φp, K. P. Adhikari, D. Adikaram, M. J. Amaryan, C. E. Hyde, S. Koirala, S. E. Kuhn, M. Mayer, I. Niculescu, Et Al., The Clas Collaboration

Physics Faculty Publications

High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γp→ϕp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the ϕ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the ϕ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- (ϕ→K⁺K⁻) and neutral- (ϕ→K⁰_SK⁰_L) K^{→ …}

Publisher’S Note: Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction 𝛾p -> Φp (Phys. Rev. C. Vol 89, 055208, 2014), K. P. Adhikari, D. Adikaram, M. J. Amaryan, C. E. Hyde, A. Klein, S. Koirala, S. E. Kuhn, M. Mayer, I. Niculescu, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

No abstract provided.

The Dijet Cross Section Measurement In Proton-Proton Collisions At A Center Of Mass Energy Of 500 Gev At Star, Grant D. Webb

Theses and Dissertations--Physics and Astronomy

Polarized deep inelastic scattering experiments play a vital role in the exploration of the spin structure of the proton. The polarized proton-proton collider at RHIC provides direct access to the gluon spin distribution through longitudinal double spin asymmetry measurements of inclusive jets, pions, and dijets. This thesis presents the measurement of the dijet double differential cross-section in proton-proton collisions at center of mass energies of √s = 500 GeV. The data represent an integrated luminosity of 8.7 pb^-1 recorded by the STAR detector during the 2009 RHIC run. A comprehensive jet analysis was performed to determine the ideal …

Comment On "Unified Formalism Of Adreev Reflection At A Ferromagnet/Superconductor Interface", M. Eschrig, A. A. Golubov, I. I. Mazin, B. Nadgorny, Y. Tanaka, O. T. Valls, Igor Žutić

Physics and Astronomy Faculty Research Publications

A Comment on the Letter by T. Y. Chen et al., Phys. Rev. Lett. 109 146602 (2012) The authors of the Letter offer a Reply.

Freeze-Out Dynamics Via Charged Kaon Femtoscopy In √ Snn = 200 Gev Central Au + Au Collisions, L. Adamczyk, E. Elnimr, S. Lapointe, C. Pruneau, J. Putschke, M. Sharma, L. H. Tarini, S. A. Voloshin, Star Collaboration

Physics and Astronomy Faculty Research Publications

We present measurements of three-dimensional correlation functions of like-sign, low-transverse-momentum kaon pairs from √s_NN=200 GeV Au+Au collisions. A Cartesian surface-spherical harmonic decomposition technique was used to extract the kaon source function. The latter was found to have a three-dimensional Gaussian shape and can be adequately reproduced by Therminator event-generator simulations with resonance contributions taken into account. Compared to the pion one, the kaon source function is generally narrower and does not have the long tail along the pair transverse momentum direction. The kaon Gaussian radii display a monotonic decrease with increasing transverse mass m_T over …

Contributions To The Cuore Collaboration, Samuel Joseph Meijer

Physics

This paper describes work done between 2010 and 2013 to contribute to the CUORE collaboration, a physics collaboration searching for neutrinoless double-beta decay in tellurium. Measurement of this decay would indicate fundamental information about the nature of the neutrino. The implementation of a parylene-coated detector frame is described. Also, a temperature stabilization system for an automated gluing system was constructed. An image recognition algorithm is described for locating spots of glue and evaluating their acceptability.

Semiclassical Partition Functions For Gravity With Cosmic Strings, Christopher L. Duston

Physics Faculty Publications

In this paper we describe an approach to construct semiclassical partition functions in gravity which are complete in the sense that they contain a complete description of the differentiable structures of the underlying 4-manifold. In addition, we find our construction naturally includes cosmic strings. We prove that the mass density of these strings uniquely specifies the topology of the leaves of a dimension 2 foliation, and conjecture that spacetime topology emerges as a result of the symmetry breaking of the fundamental fields. We discuss some possible applications of the partition functions in the fields of both quantum gravity and topological …

Photon Impact Factor And 𝑘T Factorization For Dis In The Next-To-Leading Order, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

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

Transverse Polarization Of Σ+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. Bültmann, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, B. Torayev, L. B. Weinstein

Physics Faculty Publications

Experimental results on the Σ⁺(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson Laboratory are presented. The Σ⁺(1189) was reconstructed in the exclusive reaction γ+p→K⁰_S+Σ+(1189) via the Σ+→pπ⁰ decay mode. The K⁰_S was reconstructed in the invariant mass of two oppositely charged pions with the π⁰ identified in the missing mass of the detected pπ⁺π⁻ final state. Experimental data were collected in the photon energy range Eγ=1.0 –3.5 GeV (√s range 1.66–2.73 GeV). We observe a large negative polarization …

Demonstration Of A Novel Technique To Measure Two-Photon Exchange Effects In Elastic E±P Scattering, M. Niroula, L. B. Weinstein, D. Adikaram, J. Lanchiet, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, C. E. Hyde, S.E. Kuhn, H. Seraydaryan

Physics Faculty Publications

Background: The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections.

Purpose: The TPE contributions depend on the sign of the lepton charge in e±p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e±p comparisons, which …

Deep Exclusive Π+ Electroproduction Off The Proton At Clas, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, G. E. Dodge, S. E. Kuhn, M. Mayer, C. S. Nepali, H. Seraydaryan, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The exclusive electroproduction of π ⁺ above the resonance region was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory by scattering a 6GeV continuous electron beam off a hydrogen target. The large acceptance and good resolution of CLAS, together with the high luminosity, allowed us to measure the cross section for the γ ^* p → nπ ⁺ process in 140 (Q ², x _B , t) bins: 0.16 < x _B < 0.58, 1.6 GeV² < Q ² < 4.5 GeV² and 0.1 GeV² < −t < 5.3 GeV². For most bins, the statistical accuracy is on the order of a …