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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1988

Observation of the Meissner effect in a lattice Higgs model

The lattice-regularized U(1) Higgs model in an external electromagnetic field is studied by Monte Carlo techniques. In the Coulomb phase, magnetic flux can flow through uniformly. The Higgs phase splits into a region where magnetic flux can penetrate only in the form of vortices and a region where the magnetic flux is completely expelled, the relativistic analog of the Meissner effect in superconductivity. Evidence is presented for symmetry restoration in strong external fields.

Damgaard, Poul H.↗
DOE OSTI2015

Bounce inflation cosmology with Standard Model Higgs boson

It is of great interest to connect cosmology in the early universe to the Standard Model of particle physics. In this paper, we try to construct a bounce inflation model with the standard model Higgs boson, where the one loop correction is taken into account in the effective potential of Higgs field. In this model, a Galileon term has been introduced to eliminate the ghost mode when bounce happens. Moreover, due to the fact that the Fermion loop correction can make part of the Higgs potential negative, one naturally obtains a large equation of state(EoS) parameter in the contracting phase, which can eliminate the anisotropy problem. After the bounce, the model can drive the universe into the standard higgs inflation phase, which can generate nearly scale-invariant power spectrum.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Topological self-dual configurations in a Maxwell–Higgs model with a CPT-odd and Lorentz-violating nonminimal coupling

We have studied the existence of topological self-dual configurations in a nonminimal CPT-odd and Lorentz-violating (LV) Maxwell–Higgs model, where the LV interaction is introduced by modifying the minimal covariant derivative. The Bogomol’nyi–Prasad–Sommerfield formalism has been implemented, revealing that the scalar self-interaction implying self-dual equations contains a derivative coupling. The CPT-odd self-dual equations describe electrically neutral configurations with finite total energy proportional to the total magnetic flux, which differ from the charged solutions of other CPT-odd and LV models previously studied. In particular, we have investigated the axially symmetrical self-dual vortex solutions altered by the LV parameter. For large distances, the profiles possess general behavior similar to the vortices of Abrikosov–Nielsen–Olesen. However, within the vortex core, the profiles of the magnetic field and energy can differ substantially from ones of the Maxwell–Higgs model depending if the LV parameter is negative or positive.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Natural top-bottom mass hierarchy in composite Higgs models

We consider composite two-Higgs doublet models based on gauge-Yukawa theories with strongly interacting fermions generating the top-bottom mass hierarchy. The model features a single "universal" Higgs-Yukawa coupling, $g$, which is identified with the top quark $g\equiv g_t \sim \mathcal{O}(1)$. The top-bottom mass hierarchy arises by soft breaking of a $\mathbb{Z}_2$ symmetry by a condensate of strongly interacting fermions. A mass splitting between vector-like masses of the confined techni-fermions controls this top-bottom mass hierarchy. This mechanism can be present in a variety of models based on vacuum misalignment. For concreteness, we demonstrate it in a composite two-Higgs scheme.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Gauge turbulence, topological defect dynamics, and condensation in Higgs models

The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Measurement of the branching ratios for the standard model Higgs decays into muon pairs and into Z boson pairs at a 1.4 TeV CLIC

The measurement of the Higgs production cross-section times the branching ratios for its decays into μ{sup +}μ{sup −} and ZZ* pairs at a 1.4 TeV CLIC collider is investigated in this paper. The Standard Model Higgs boson with a mass of 126 GeV is dominantly produced via WW fusion in e{sup +}e{sup −} collisions at 1.4 TeV centre-of-mass energy. Analyses of both decay channels are based on a full simulation of the CLIC-ILD detector. All relevant physics and beam-induced background processes are taken into account. An integrated luminosity of 1.5 ab{sup −1} and unpolarised beams are assumed. For the H→ZZ* decay, the purely hadronic final state (ZZ* → qq̄qq̄) is considered as well as ZZ* decays into two jets and two leptons (ZZ* → qql{sup +}l{sup −}). It is shown that the branching ratio for the Higgs decay into a muon pair times the Higgs production cross-section can be measured with 38% statistical uncertainty. It is also shown that the statistical uncertainty of the Higgs branching ratio for decay into a Z boson pair times the Higgs production cross-section can be measured with a precision of 18.3% and 5.6% for the hadronic and semi-leptonic ZZ* decays, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

A search for the standard model Higgs boson decaying to charm quarks

A direct search for the standard model Higgs boson, H, produced in association with a vector boson, V (W or Z), and decaying to a charm quark pair is presented. The search uses a data set of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb$^{−1}$, collected by the CMS experiment at the LHC in 2016, at a centre-of-mass energy of 13 TeV. The search is carried out in mutually exclusive channels targeting specific decays of the vector bosons: W → ℓν, Z → ℓℓ, and Z → νν, where ℓ is an electron or a muon. To fully exploit the topology of the H boson decay, two strategies are followed. In the first one, targeting lower vector boson transverse momentum, the H boson candidate is reconstructed via two resolved jets arising from the two charm quarks from the H boson decay. A second strategy identifies the case where the two charm quark jets from the H boson decay merge to form a single jet, which generally only occurs when the vector boson has higher transverse momentum. Both strategies make use of novel methods for charm jet identification, while jet substructure techniques are also exploited to suppress the background in the merged-jet topology. The two analyses are combined to yield a 95% confidence level observed (expected) upper limit on the cross section $ \sigma \left(\mathrm{VH}\right)\mathrm{\mathcal{B}}\left(\mathrm{H}\to \mathrm{c}\overline{\mathrm{c}}\right) $ of 4.5 $ \left({2.4}_{-0.7}^{+1.0}\right) $ pb, corresponding to 70 (37) times the standard model prediction.[graphic not available: see fulltext]

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Search for beyond the standard model Higgs bosons decaying into a $ \mathrm{b}\overline{\mathrm{b}} $ pair in pp collisions at $ \sqrt{s}=13 $ TeV

A search for Higgs bosons that decay into a bottom quark-antiquark pair and are accompanied by at least one additional bottom quark is performed with the CMS detector. The data analyzed were recorded in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} =$ 13 TeV at the LHC, corresponding to an integrated luminosity of 35.7 fb$^{-1}$. The final state considered in this analysis is particularly sensitive to signatures of a Higgs sector beyond the standard model, as predicted in the generic class of two Higgs doublet models (2HDMs). No signal above the standard model background expectation is observed. Stringent upper limits on the cross section times branching fraction are set for Higgs bosons with masses up to 130 GeV. Lastly, the results are interpreted within several MSSM and 2HDM scenarios.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Confinement and String Breaking in the Compact Abelian Higgs Model

While real-time simulation of Quantum Chromodynamics remains technologically out of reach, simplified models for studying elements of QCD phenomenology abound. This work presents a simple model, a spin-1 truncation of the Compact Abelian Higgs Model simulated on qutrit sites, in which confinement and string breaking is accessible to current simulation methods. In the low-energy regime of 1+1D scalar electrodynamics, the heavy modes are integrated out, producing a spin chain effective Hamiltonian in which Gauss' law is implicitly satisfied. We study the spectrum of string-like excitations using DMRG methods on the order of 100 sites. We demonstrate that an added, local chemical potential, playing a role analogous to external charges, permits parameter-dependent measurements of physical features of interest like the string tension and effective meson mass. Varying the chemical potential also permits a characterization of string stability not assessed in prior studies of confining lattice models.

Senseman, Blake [Iowa U.]↗
DOE OSTI2018

Coscattering/coannihilation dark matter in a fraternal twin Higgs model

Dark matter candidates arise naturally in many models that address the hierarchy problem. In the fraternal twin Higgs model which could explain the absence of the new physics signals at the Large Hadron Collider (LHC), there are several viable dark matter candidates. In this paper we study the twin neutrino in the mass range ~0.1-10 GeV as the dark matter. The thermal relic density is determined by the interplay of several annihilation and scattering processes between the twin neutrino, twin tau, and twin photon, depending on the order of the freeze-out temperatures of these processes. Besides the common coannihilation scenario where the relic density is controlled by the twin tau annihilation, it can realize the recently discovered coscattering phase if the scattering of the twin neutrino into the twin tau freezes out earlier than the twin tau annihilation. We also provide a method to calculate the thermal relic density in the intermediate regime where both coannihilation and coscattering processes contribute to the determination of the dark matter density. We show that the right amount of dark matter can be obtained in various scenarios in different regions of the parameter space. The current experimental constraints and future probes into the parameter space from direct detections, cosmological and astrophysical bounds, dark photon searches, and displaced decays at colliders, are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Gauge-invariant implementation of the Abelian-Higgs model on optical lattices

We present a gauge-invariant effective action for the Abelian Higgs model (scalar electrodynamics) with a chemical potential $\mu$ on a 1+1 dimensional lattice. This formulation provides an expansion in the hopping parameter $\kappa$ which we test with Monte Carlo simulations for a broad range of the inverse gauge coupling $\beta_{pl}=1/g^2$ and small values of the scalar self-coupling $\lambda$. In the opposite limit of infinitely large $\lambda$, the partition function can be written as a traced product of local tensors which allows us to write exact blocking formulas. Gauss's law is automatically satisfied and the introduction of $\mu$ has consequences only if we have an external electric field, $g^2=0$ or an explicit gauge symmetry breaking. The time continuum limit of the blocked transfer matrix can be obtained numerically and, for $g^2=0$ and a spin-1 truncation, the small volume energy spectrum is identical to the low energy spectrum of a two-species Bose-Hubbard model in the limit of large on-site repulsion. We extend this procedure for finite $\beta_{pl}$ and derive a spin-1 approximation of the Hamiltonian. It involves new terms corresponding to transitions among the two species in the Bose-Hubbard model. Finally, we propose an optical lattice implementations involving a ladder structure.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

$S$ parameter from a prototype composite-Higgs model

We have calculated the low-energy constant $L_{10}$ in a prototype composite Higgs model with dynamical fermions in two different representations of the gauge group. The resulting contribution of the new strong sector to the $S$ parameter is consistent with current bounds on the vacuum misalignment parameter. We end with a brief discussion of future directions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks using a matrix element method

A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a data sample corresponding to an integrated luminosity of 19.5fb -1 collected by the CMS experiment at the LHC in pp collisions at a centre-of-mass energy of 8TeV. In order to separate the signal from the larger tt¯ + jets background, this analysis uses a matrix element method that assigns a probability density value to each reconstructed event under signal or background hypotheses. The ratio between the two values is used in a maximum likelihood fit to extract the signal yield. The results are presented in terms of the measured signal strength modifier, μ, relative to the standard model prediction for a Higgs boson mass of 125GeV. The observed (expected) exclusion limit at a 95 % confidence level is μ < 4.2 (3.3), corresponding to a best fit value μ^ = 1.2 +1.6 -1.5 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for the $ b\overline{b} $ decay of the Standard Model Higgs boson in associated ( W/Z ) H production with the ATLAS detector

A search for the $ b\overline{b} $ decay of the Standard Model Higgs boson is performed with the ATLAS experiment using the full dataset recorded at the LHC in Run 1. The integrated luminosities used are 4.7 and 20.3 fb -1 from pp collisions at √s = 7 and 8 TeV, respectively. The processes considered are associated (W/Z)H production, where W → eν/μν, Z → ee/μμ and Z → νν. The observed (expected) deviation from the background-only hypothesis corresponds to a significance of 1.4 (2.6) standard deviations and the ratio of the measured signal yield to the Standard Model expectation is found to be μ = 0.52 ± 0.32 (stat.) ± 0.24 (syst.) for a Higgs boson mass of 125.36 GeV. The analysis procedure is validated by a measurement of the yield of (W/Z)Z production with Z → $ b\overline{b} $ in the same final states as for the Higgs boson search, from which the ratio of the observed signal yield to the Standard Model expectation is found to be 0.74 ± 0.09 (stat.) ± 0.14 (syst.).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Pseudoscalar pair production via off-shell Higgs in composite Higgs models

We propose a new type of search for a pseudoscalar particle $\eta$ pair produced via an off-shell Higgs, $pp$ → $h*$ → $\eta\eta$. The search is motivated by a composite Higgs model in which the $\eta$ is extremely narrow and decays almost exclusively into Z in the mass range 65 $\lesssim$ GeV $m_{\eta}$ $\lesssim$ 160 GeV. We devise an analysis strategy to observe the novel Zγ Zγ channel and estimate potential bounds on the Higgs-$\eta$ coupling. The experimental sensitivity to the signatures depends on the power to identify fake photons and on the ability to predict large photon multiplicities. This search allows us to exclude large values of the compositeness scale $f$, being thus complementary to other typical processes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Search for bottom quark associated production of the standard model Higgs boson in final states with leptons in proton-proton collisions at $\sqrt{s}$ =13 TeV

This Letter presents the first search for bottom quark associated production of the standard model Higgs boson, in final states with leptons. Higgs boson decays to pairs of tau leptons and pairs of leptonically decaying W bosons are considered. The search is performed using data collected from 2016 to 2018 by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb -1 . Upper limits at the 95% confidence level are placed on the signal strength for Higgs boson production in association with bottom quarks; the observed (expected) upper limit is 3.7 (6.1) times the standard model prediction

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for a Standard Model Higgs Boson in the Channel $VH\to VWW$ with Leptons and Hadronic $\tau$ in the Full CDF Run II Data Set

We present the results of the CDF search for a Standard Model Higgs boson decaying into a pair of W bosons with electrons, muons and hadronically decaying taus in the final state. In particular, we investigate a channel with three objects, two leptons and a tau. In 9.7 fb -1 of data we expect 40.0 ± 5.4 background events and 0.54 ± 0.05 signal events for a Higgs mass hypothesis of 160 GeV/c 2 , whereas in data we count 28 events. We set a 95% C.L. upper limit on σ/σSM of 12.6 for a Higgs mass hypothesis of 160 GeV/c 2 . The expected 95% C.L. upper limit for the same mass is 12.4. Results for other ninete 0 GeV/c2 to 200 GeV/c 2 are also presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Sneutrino Higgs models explain lepton non-universality in eejj, eνjj excesses

Recent searches for first-generation leptoquarks and heavy right-handed W R bosons have seen excesses in final states with electrons and jets. A bizarre property of these excesses is that they appear to violate lepton universality. With these results in mind, we study the phenomenology of supersymmetric models in which the Higgs arises as the sneutrino in an electron supermultiplet. Since the electron is singled out in this approach, one can naturally account for the lepton flavor structure of the excesses. In this work, we show that in such a framework, one can significantly alleviate the tension between the Standard Model and the data and yet evade current constraints from other searches. Finally we point out that correlated excesses are expected to be seen in future multilepton searches.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗