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Open Access Publications from the University of California

Scholarly Works (10 results)

  • Article
  • Peer Reviewed
LBL Publications (2018)
We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter a allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.
    Cover page: Jet angularity measurements for single inclusive jet production
    • Thesis
    • Peer Reviewed
    UCLA Electronic Theses and Dissertations (2014)

    Objective:

    The aim of this clinical pilot study is to see if a novel mini-implant assisted rapid palatal expander (MARPE) has similar dental and skeletal treatment effects in an Early Treatment Group (ETG) and a Late Treatment Group (LTG) through the use of Cone Beam Computed Tomography (CBCT) analysis.

    Methods:

    Orthodontic patients requiring MARPE were asked to participate in a clinical study. A pilot study consisting of ten patients were grouped into an ETG or LTG according to their Cervical Vertebral Maturation Stage (CVMS). Five patients with CVMS stage 1-4 were placed in the ETG, and 5 patients with CVMS stage 5 were placed in the LTG. CBCTs were taken for initial records (T0), immediately after expansion (T1), and 6 months after expansion was complete (T2). Skeletal versus dental effects, and palatal volume were measured between T0, T1 and T2, and between groups, using Dolphin Imaging and itk-SNAP.

    Results:

    Similar results were seen between groups for all the skeletal outcomes except at NW, BBW, TDTZ from T1-T0, Basal Bone Width and Buccal bone width at 14mm from T2-T1, and MW, and TDTZ from T2-T0, where these measures showed statistical significance between groups. The ratio of mid-palatal suture opening at M1 and expansion width in the appliance at T1, was 69% in the ETG and 34% in the LTG. There was 6° of dental tipping in the LTG, and 1° of tooth uprighting in the ETG after expansion. Buccal bone width at both 11 and 14 mm decreased during expansion, and then increased during the retention phase in both groups. Palatal volume increased following expansion, with a slight decrease during the retention phase. In the ETG there was 61% skeletal expansion, 10% bone bending and 29% dental tipping, compared to 34% skeletal expansion, 4% bone bending, and 62% dental tipping in the LTG.

    Conclusion:

    The use of a novel MARPE has overcome the limitations of a traditional tooth-anchored appliance, allowing force to be directed adjacent to the mid-palatal suture, opening up the suture and achieving true skeletal expansion in a late treatment group. This pilot study has shown significant differences in certain measures between the ETG and LTG, however increasing our sample size will determine if there is a true difference between groups.

      Cover page: Effects of a Novel Mini-Implant Assissted RPE in an Early and Late Treatment Group
      • Article
      • Peer Reviewed
      LBL Publications (2020)
      We study the jet energy drop, which is the relative difference between the groomed and ungroomed jet energy or transverse momentum. It is one of the fundamental quantities that characterizes the impact of grooming on jets produced in high energy collisions. We consider three different grooming algorithms i) soft drop, ii) iterated soft drop, and iii) trimming. We carry out the resummation of large logarithms of the jet energy drop, the jet radius as well as relevant grooming parameters at next-to-leading logarithmic (NLL′) accuracy. In addition, we account for non-global and clustering logarithms, and determine the next-to-leading order corrections. For soft drop we perform a joint resummation of the jet energy drop and the groomed jet radius, which is necessary to achieve the correct all-order structure of the cross section, in particular for the Sudakov-safe case of soft drop with β = 0. We present numerical results for LHC energies and compare to Pythia simulations as well as CMS data. Our factorization framework predicts the onset of nonperturbative effects in the jet energy distribution, in line with what we find in Pythia. The jet energy drop observables stand out because they only probe soft radiation, making them ideal candidates for the tuning of parton shower Monte Carlo event generators and for probing medium effects in heavy-ion collisions.
        Cover page: Jet energy drop
        • Article
        • Peer Reviewed
        LBL Publications (2018)
        We study jet mass distributions measured in the single inclusive jet production in proton-proton collisions pp → jet+X at the LHC. We consider both standard ungroomed jets as well as soft drop groomed jets. Within the Soft Collinear Effective Theory (SCET), we establish QCD factorization theorems for both cases and we study their relation. The developed framework allows for the joint resummation of several classes of logarithmic corrections to all orders in the strong coupling constant. For the ungroomed case, we resum logarithms in the jet radius parameter and in the small jet mass. For the groomed case, we resum in addition the logarithms in the soft threshold parameter zcut which is introduced by the soft drop grooming algorithm. In this way, we are able to reliably determine the absolute normalization of the groomed jet mass distribution in proton-proton collisions. All logarithmic corrections are resummed to the next-to-leading logarithmic accuracy. We present numerical results and compare with the available data from the LHC. For both the groomed and ungroomed jet mass distributions we find very good agreement after including non-perturbative corrections.
          Cover page: The groomed and ungroomed jet mass distribution for inclusive jet production at the LHC
          • Article
          • Peer Reviewed
          LBL Publications (2022)
          Grooming techniques, such as soft drop, play a central role in reducing sensitivity of jets to e.g. underlying event and hadronization at current collider experiments. The momentum sharing fraction zg, of the two branches in a jet that pass the soft drop condition, is one of the most important observables characterizing a collinear splitting inside the jet, and directly probes the QCD splitting functions. In this work, we present a factorization framework that enables a systematic calculation of the corresponding cross section beyond modified leading-logarithmic (MLL) accuracy, showing that this measurement is not only sensitive to the QCD charge but also the spin of the parton that initiates the jet. Our results at next-to-leading logarithmic (NLL′) accuracy include non-global logarithms, and provide a first meaningful assessment of the perturbative uncertainty. We present a comparison to the available experimental data from ALICE, ATLAS, and STAR and find excellent agreement.
            Cover page: The soft drop momentum sharing fraction z g beyond leading-logarithmic accuracyCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2024)
            We study the azimuthal angle dependence of the energy-energy correlators in the back-to-back region for e+e− annihilation and deep inelastic scattering (DIS) processes with general polarization of the proton beam. We demonstrate that the polarization information of the beam and the underlying partons from the hard scattering is propagated into the azimuthal angle dependence of the energy-energy correlators. In the process, we define the Collins-type EEC jet functions and introduce a new EEC observable using the lab-frame angles in the DIS process. Furthermore, we extend our formalism to explore the two-point energy correlation between hadrons with different quantum numbers in the back-to-back limit. We find that in the Operator Product Expansion (OPE) region the nonperturbative information is entirely encapsulated by a single number. Using our formalism, we present several phenomenological studies that showcase how energy correlators can be used to probe transverse momentum dependent structures.
              Cover page: Probing transverse momentum dependent structures with azimuthal dependence of energy correlatorsCreative Commons 'BY' version 4.0 license
              • Article
              • Peer Reviewed
              LBL Publications (2022)
              We present simulations of nonequilibrium dynamics of quantum field theories on digital quantum computers. As a representative example, we consider the Schwinger model, a (1+1)-dimensional U(1) gauge theory, coupled through a Yukawa-type interaction to a thermal environment described by a scalar field theory. We use the Hamiltonian formulation of the Schwinger model discretized on a spatial lattice. With the thermal scalar fields traced out, the Schwinger model can be treated as an open quantum system and its real-time dynamics are governed by a Lindblad equation in the Markovian limit. The interaction with the environment ultimately drives the system to thermal equilibrium. In the quantum Brownian motion limit, the Lindblad equation is related to a field theoretical Caldeira-Leggett equation. By using the Stinespring dilation theorem with ancillary qubits, we perform studies of both the nonequilibrium dynamics and the preparation of a thermal state in the Schwinger model using IBM's simulator and quantum devices. The real-time dynamics of field theories as open quantum systems and the thermal state preparation studied here are relevant for a variety of applications in nuclear and particle physics, quantum information and cosmology.
                Cover page: Quantum simulation of nonequilibrium dynamics and thermalization in the Schwinger model
                • Article
                • Peer Reviewed
                LBL Publications (2020)
                We present results for the soft drop groomed jet radius Rg at next-to-leading logarithmic accuracy. The radius of a groomed jet which corresponds to the angle between the two branches passing the soft drop criterion is one of the characteristic observables relevant for the precise understanding of groomed jet substructure. We establish a factorization formalism that allows for the resummation of all relevant large logarithms, which is based on demonstrating the all order equivalence to a jet veto in the region between the boundaries of the groomed and ungroomed jet. Non-global logarithms including clustering effects due to the Cambridge/Aachen algorithm are resummed to all orders using a suitable Monte Carlo algorithm. We perform numerical calculations and find a very good agreement with Pythia 8 simulations. We provide theoretical predictions for the LHC and RHIC.
                  Cover page: The soft drop groomed jet radius at NLL
                  • Article
                  • Peer Reviewed
                  Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 46 (2024)
                  Pointing is an intuitive and commonplace communication modality. In human-robot collaborative tasks, human pointing has been modeled using a variety of approaches, such as the forearm vector or the vector from eye to hand. However, models of the human pointing vector have not been uniformly or comprehensively evaluated. We performed a user study to compare five different representations of the pointing vector and their accuracies in identifying the human's intended target in an object selection task. We also compare the vectors' performances to that of domestic dogs to assess a non-human baseline known to be successful at following human points. Additionally, we developed an observation model to transform the vector into a probability map for object search. We implemented our system on our robot, enabling it to locate and fetch the user's desired objects efficiently and accurately.
                    Cover page: Find it like a dog: Using Gesture to Improve Object SearchCreative Commons 'BY' version 4.0 license
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2022)
                    RORγt is known to instruct the differentiation of T helper 17 (TH17) cells that mediate the pathogenesis of autoimmune diseases. However, it remains unknown whether RORγt plays a distinct role in the differentiation and effector function of TH17 cells. Here, we show that mutation of RORγt lysine-256, a ubiquitination site, to arginine (K256R) separates the RORγt role in these two functions. Preventing ubiquitination at K256 via arginine substitution does not affect RORγt-dependent thymocyte development, and TH17 differentiation in vitro and in vivo, however, greatly impaired the pathogenesis of TH17 cell-mediated experimental autoimmune encephalomyelitis (EAE). Mechanistically, K256R mutation impairs RORγt to bind to and activate Runx1 expression critical for TH17-mediated EAE. Thus, RORγt regulates the effector function of TH17 cells in addition to TH17 differentiation. This work informs the development of RORγt-based therapies that specifically target the effector function of TH17 cells responsible for autoimmunity.
                      Cover page: Decoupling the role of RORγt in the differentiation and effector function of TH17 cells
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