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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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At least 1,081 records · Page 60
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DOE OSTI2011

Search for the fourth standard model family

Existence of the fourth family follows from the basics of the standard model (SM) and the actual mass spectrum of the third family fermions. We discuss possible manifestations of the fourth SM family at existing and future colliders. The LHC and Tevatron potentials to discover the fourth SM family have been compared. The scenario with dominance of the anomalous decay modes of the fourth-family quarks has been considered in detail.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Higgs bosons in a minimal R-parity conserving left-right supersymmetric model

We revisit the Higgs sector of the left-right supersymmetric model. We study the scalar potential in a version of the model in which the minimum is the charge-conserving vacuum state, without R-parity violation or additional nonrenormalizable terms in the Lagrangian. We analyze the dependence of the potential and of the Higgs mass spectrum on the various parameters of the model, pinpointing the most sensitive ones. We also show that the model can predict light neutral flavor-conserving Higgs bosons, while the flavor-violating ones are heavy and within the limits from K{sup 0}-K{sup 0}, D{sup 0}-D{sup 0}, and B{sub d,s}{sup 0}-B{sub d,s}{sup 0} mixings. We study variants of the model in which at least one doubly charged Higgs boson is light and show that the parameter space for such Higgs masses and mixings is very restrictive, thus making the model more predictive.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Novel explanation of charmoniumlike structure in e{sup +}e{sup -}{yields}{psi}(2S){pi}{sup +}{pi}{sup -}

We first present a nonresonant description to charmoniumlike structure Y(4360) in the {psi}(2S){pi}{sup +}{pi}{sup -} invariant mass spectrum of the e{sup +}e{sup -}{yields}{psi}(2S){pi}{sup +}{pi}{sup -} process. The Y(4360) structure is depicted well by the interference effect of the production amplitudes of e{sup +}e{sup -}{yields}{psi}(2S){pi}{sup +}{pi}{sup -} via the intermediate charmonia {psi}(4160)/{psi}(4415) and direct e{sup +}e{sup -} annihilation into {psi}(2S){pi}{sup +}{pi}{sup -}. This fact shows that Y(4360) is not a genuine resonance, which naturally explains why Y(4360) was only reported in its hidden-charm decay channel {psi}(2S){pi}{sup +}{pi}{sup -} and was not observed in the exclusive open-charm decay channel or R-value scan.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Constraints on the induced gravitational wave background from primordial black holes

We perform a consistent calculation of primordial black hole (PBH) mass spectrum and second-order induced gravitational wave (GW) background produced from primordial scalar perturbations in radiation era of the early Universe. It is shown that the maximal amplitudes of the second-order GW spectrum that can be approached without conflicting with the PBH data do not depend significantly on the shape of primordial perturbation spectrum. The constraints on the GW background obtained in previous works are extended to a wider GW frequency range. We discuss the applicability of the currently available pulsar timing limits for obtaining the constraints on scalar power spectrum and PBH abundance and show that they can be used for strongly constraining the PBH number density in the PBH mass range {approx}(0.03-10)M{sub {center_dot}}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Charged bottomoniumlike states Z{sub b}(10610) and Z{sub b}(10650) and the {Upsilon}(5S){yields}{Upsilon}(2S){pi}{sup +}{pi}{sup -} decay

Inspired by the newly observed two charged bottomoniumlike states, we consider the possible contribution from the intermediate Z{sub b}(10610) and Z{sub b}(10650) states to the {Upsilon}(5S){yields}{Upsilon}(2S){pi}{sup +}{pi}{sup -} decay process, which naturally explains Belle's previous observation of the anomalous {Upsilon}(2S){pi}{sup +}{pi}{sup -} production near the peak of {Upsilon}(5S) at {radical}(s)=10.87 GeV [K. F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008)]. The resulting d{Gamma}({Upsilon}(5S){yields}{Upsilon}(2S){pi}{sup +}{pi}{sup -})/dm{sub {pi}}{sup +}{sub {pi}}{sup -} and d{Gamma}({Upsilon}(5S){yields}{Upsilon}(2S){pi}{sup +}{pi}{sup -})/dcos{theta} distributions agree with Belle's measurement after inclusion of these Z{sub b} states. This formalism also reproduces the Belle observation of the double-peak structure and its reflection in the {Upsilon}(2S){pi}{sup +} invariant mass spectrum of the {Upsilon}(5S){yields}{Upsilon}(2S){pi}{sup +}{pi}{sup -} decay.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Charged bottomoniumlike structures in the hidden-bottom dipion decays of {Upsilon}(11020)

Under the Initial Single Pion Emission mechanism, we study the hidden-bottom dipion decays of {Upsilon}(11020), i.e., {Upsilon}(11020){yields}{Upsilon}(nS){pi}{sup +}{pi}{sup -} (n=1, 2, 3) and {Upsilon}(11020){yields}h{sub b}(mP){pi}{sup +}{pi}{sup -} (m=1, 2). We predict explicit sharp peak structures close to the BB* and B*B* thresholds and their reflections in the {Upsilon}(1S){pi}{sup +}, {Upsilon}(2S){pi}{sup +} and h{sub b}(1P){pi}{sup +} invariant mass spectrum distributions. We suggest that a future experiment, i.e., Belle, BABAR, and forthcoming BelleII or Super-B, carry out the search for these novel phenomena, which can provide important tests to the Initial Single Emission mechanism existing in higher bottomonia.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Mass spectrum and thermodynamics of quasiconformal gauge theories from gauge/gravity duality

We use gauge/gravity duality to study simultaneously the mass spectrum and the thermodynamics of a generic quasiconformal gauge theory, specified by its beta function. The beta function of a quasiconformal theory almost vanishes, and the coupling is almost constant between two widely separated energy scales. Depending on whether the gravity dual has a black hole or not, the mass spectrum is either a spectrum of quasinormal oscillations or a normal T=0 mass spectrum. The mass spectrum is quantitatively correlated with the thermal properties of the system. As the theory approaches conformality, the masses have to vanish. We show that in this limit, the masses calculated via gauge/gravity duality satisfy expected scaling properties.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Reconstructing the heavy resonance at hadron colliders

We investigate the method for constructing the invariant mass using the M{sub T2}-assisted on-shell (MAOS) approximation to the invisible particle momenta in the cascade decays of a new particle resonance produced at hadron colliders. We note that the MAOS reconstruction can be defined in several different ways, while keeping the efficiency of approximation at a similar level, and one of them provides a unique solution for each event. It is shown that the invariant mass distribution constructed with the MAOS momenta exhibits a peak at the heavy resonance mass, regardless of the chosen MAOS scheme and the detailed mass spectrum of the particles in the cascade. We stress that the MAOS invariant mass can be used as a clean signal of new particle resonance produced at the Large Hadron Collider, as well as a model-independent method to measure the masses of new particles involved in the event.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Search for Dijet Resonances in 7 TeV pp Collisions at CMS

A search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9 inverse pb collected by the CMS experiment at the LHC. Upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% CL: string resonances, with mass less than 2.50 TeV, excited quarks, with mass less than 1.58 TeV, and axigluons, colorons, and E_6 diquarks, in specific mass intervals. This extends previously published limits on these models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Hadron Mass Spectrum from Lattice QCD

Finite temperature lattice simulations of quantum chromodynamics (QCD) are sensitive to the hadronic mass spectrum for temperatures below the 'critical' temperature T{sub c}{approx_equal}160 MeV. We show that a recent precision determination of the QCD trace anomaly shows evidence for the existence of a large number of hadron states beyond those known from experiment. The lattice results are well represented by an exponentially growing mass spectrum up to a temperature T=155 MeV. Using simple parametrizations of the hadron mass spectrum we show how one may estimate the total spectral weight in these yet undermined states.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Confirmation of the X(1835) and Observation of the Resonances X(2120) and X(2370) in J/{psi}{yields}{gamma}{pi}{sup +}{pi}{sup -}{eta}'

With a sample of (225.2{+-}2.8)x10{sup 6} J/{psi} events registered in the BESIII detector, J/{psi}{yields}{gamma}{pi}{sup +}{pi}{sup -}{eta}' is studied using two {eta}{sup '} decay modes: {eta}{sup '}{yields}{pi}{sup +}{pi}{sup -}{eta} and {eta}{sup '}{yields}{gamma}{rho}{sup 0}. The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20{sigma}. In addition, in the {pi}{sup +}{pi}{sup -}{eta}' invariant-mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2{sigma} and 6.4{sigma}, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Search for Neutral Minimal Supersymmetric Standard Model Higgs Bosons Decaying to Tau Pairs in pp Collisions at {radical}(s)=7 TeV

A search for neutral minimal supersymmetric standard model (MSSM) Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36 pb{sup -1} recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum. The resulting upper limits on the Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, yield stringent new bounds in the MSSM parameter space.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Abashian-Booth-Crowe Effect in Basic Double-Pionic Fusion: A New Resonance?

We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn{yields}d{pi}{sup 0}{pi}{sup 0} over the full energy region of the ABC effect, a pronounced low-mass enhancement in the {pi}{pi}-invariant mass spectrum. The measurements, which cover also the transition region to the conventional t-channel {Delta}{Delta} process, were performed with the upgraded WASA detector setup at COSY. The data reveal the Abashian-Booth-Crowe effect to be uniquely correlated with a Lorentzian energy dependence in the integral cross section. The observables are consistent with a narrow resonance with m=2.37 GeV, {Gamma}{approx_equal}70 MeV and I(J{sup P})=0(3{sup +}) in both pn and {Delta}{Delta} systems. Necessary further tests of the resonance interpretation are discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗