Thu·Jun 8, 2017Thursday·June 8, 2017

1. 01*

   Stop Co-Annihilation in the Minimal Supersymmetric Standard Model Revisited

   Aaron Pierce🇺🇸 · Nausheen R. Shah🇺🇸 · Stefan Vogl🇩🇪

   We re-examine the stop co-annihilation scenario of the Minimal Supersymmetric Standard Model, wherein a bino-like lightest supersymmetric particle has a thermal relic density set by co-annihilations with a scalar partner of the top quark in the early universe. We concentrate on the case where only the top partner sector is relevant for the cosmology, and other particles are heavy. We discuss the cosmology with focus on low energy parameters and an emphasis on the implications of the measured Higgs boson mass and its properties. We find that the irreducible direct detection signal correlated with this cosmology is generically well below projected experimental sensitivity, and in most cases lies below the neutrino background. A larger, detectable, direct detection rate is possible, but is unrelated to the co-annihilation cosmology. LHC searches for compressed spectra are crucial for probing this scenario.

   hep-phPRD(2018)·17 citations
2. 02*

   BBN for the LHC: constraints on lifetimes of the Higgs portal scalars

   Anthony Fradette🇨🇦 · Maxim Pospelov🇨🇦

   LHC experiments can provide a remarkable sensitivity to exotic metastable massive particles, decaying with significant displacement from the interaction point. The best sensitivity is achieved to models where the production and decay occur due to different coupling constants, and the lifetime of exotic particles determines the probability of decay within a detector. The lifetimes of such particles can be independently limited from standard cosmology, in particular the Big Bang Nucleosynthesis. In this paper, we analyze the constraints on the simplest scalar model coupled through the Higgs portal, where the production occurs via $h\to SS$, and the decay is induced by the small mixing angle of the Higgs field $h$ and scalar $S$. We find that throughout the most part of the parameter space, $2m_{\mu }<m_S<m_h/2$, the lifetimes of exotic particle has to be less than 0.1 seconds, while below $2m_{\mu }$ it could grow to about a second. The strong constraints on lifetimes are induced by the nucleonic and mesonic decays of scalars that tend to raise the $n/p$ ratio. Strong constraints on lifetimes of the minimal singlet extensions of the Higgs potential is a welcome news for the MATHUSLA proposal that seeks to detect displaced decays of exotic particles produced in the LHC collisions. We also point out how more complicated exotic sectors could evade the BBN lifetime constraints.

   hep-phhep-exPRD(2017)·139 citations
3. 03*

   Identifying a light charged Higgs boson at the LHC Run II

   Abdesslam Arhrib🇲🇦 · Rachid Benbrik🇲🇦 · Rikard Enberg🇸🇪 · William Klemm🇸🇪 · Stefano Moretti🇬🇧 · Shoaib Munir🇰🇷

   We analyse the phenomenological implications of a light Higgs boson, $h$, within the CP-conserving 2-Higgs Doublet Model (2HDM) Type-I, for the detection prospects of the charged $H^{\pm }$ state at Run II of the Large Hadron Collider (LHC), assuming $\sqrt{s}=13$ TeV as energy and $\mathcal{O}(100{\mathrm{fb}}^{-1})$ as luminosity. When sufficiently light, this $h$ state can open up the bosonic decay channel $H^{\pm }\to W^{\pm (\ast )}h$, which may have a branching ratio significantly exceeding those of the $H^{\pm }\to \tau \nu$ and $H^{\pm }\to cs$ channels. We perform a broad scan of the 2HDM Type-I parameter space, assuming the heavier of the two CP-even Higgs bosons, $H$, to be the observed SM-like state with a mass near 125 GeV. Through these scans we highlight regions in which $m_{H^{\pm }}<m_t+m_b$ that are still consistent with the most recent limits from experimental searches. We find in these regions that, when the $H^{\pm }\to W^{\pm (\ast )}h$ decay mode is the dominant one, the $h$ can be highly fermiophobic, with a considerably large decay rate in the $\gamma \gamma$ channel. This can result in the total cross section of the $\sigma (pp\to H^{\pm }h\to W^{\pm (\ast )}+4\gamma )$ process reaching up to $\mathcal{O}(100\mathrm{fb})$. We therefore investigate the possibility of observing this spectacular signal at the LHC Run II.

   hep-phPLB(2017)·38 citations
4. 04*

   Analysis of soft wall AdS / QCD potentials to obtain melting temperature of scalar hadrons

   Alfredo Vega🇨🇱 · Adolfo Ibañez🇨🇱

   We consider an analysis of potentials related to Schrödinger-type equations for scalar fields in a 5D AdS black hole background with dilaton in order to get melting temperatures for different hadrons in a thermal bath. The approach does not consider calculations of spectral functions and it is easy to get results for hadrons with an arbitrary number of constituents. We present results for scalar mesons, glueballs, hybrid mesons and tetraquarks, and we show that mesons are more resistant to being melted in a thermal bath than other scalar hadrons, and in general the melting temperature increases when hadrons contain heavy quarks.

   hep-phhep-thEPJA(2017)·14 citations
5. 05*

   Accessing the nucleon transverse structure in inclusive deep inelastic scattering

   Alberto Accardi🇺🇸 · Alessandro Bacchetta🇮🇹

   We revisit the standard analysis of inclusive Deep Inelastic Scattering off nucleons taking into account the fact that on-shell quarks cannot be present in the final state, but they rather decay into hadrons - a process that can be described in terms of suitable "jet" correlators. As a consequence, a spin-flip term associated with the invariant mass of the produced hadrons is generated non perturbatively and couples to the target's transversity distribution function. In inclusive cross sections, this provides an hitherto neglected and large contribution to the twist-3 part of the g2 structure function, that can explain the discrepancy between recent calculations and fits of this quantity. It also provides an extension of the Burkhardt-Cottingham sum rule, putting constraints on the small-x behavior of the transversity function, as well as an extension of the Efremov-Teryaev-Leader sum rule, suggesting a novel way to measure the tensor charge of the proton.

   hep-phhep-exPLB(2017)·28 citations
6. 06*

   Comparison of the Structure Function F2 as Measured by Charged Lepton and Neutrino Scattering from Iron Targets

   Narbe Kalantarians🇺🇸 · Eric Christy🇺🇸 · Cynthia Keppel🇺🇸

   A comparison study of world data for the structure function F2 for Iron, as measured by both charged lepton and neutrino scattering experiments, is presented. Consistency of results for both charged lepton and neutrino scattering is observed for the full global data set in the valence regime. Consistency is also observed at low x for the various neutrino data sets, as well as for the charged lepton data sets, independently. However, data from the two probes exhibit differences on the order of 15% in the shadowing/anti-shadowing transition region where the Bjorken scaling variable x is < 0.15. This observation is indicative that neutrino probes of nucleon structure might be sensitive to different nuclear effects than charged lepton probes. Details and results of the data comparison are here presented.

   hep-phPRC(2017)·24 citations
7. 07*

   Texture zeros of low-energy Majorana neutrino mass matrix in 3+1 scheme

   Debasish Borah🇮🇳 · Monojit Ghosh🇯🇵 · Shivani Gupta🇦🇺 · Sushant K. Raut🇰🇷

   In this work we revisit the zero textures in low energy Majorana neutrino mass matrix when the active neutrino sector is extended by a light sterile neutrino in the eV scale i.e., the 3+1 scheme. In 3+1 scenario, the low energy neutrino mass matrix ($m_{\nu }$) has ten independent elements. Thus in principle one can have minimum one-zero texture to maximum ten-zero texture. We summarize the previous results of one, two, three and four-zero textures which already exist in the literature and present our new results on five-zero textures. In our analysis we find that among six possible five-zero textures, only one is allowed by the present data. We discuss possible theoretical model which can explain the origin of the allowed five-zero texture and discuss other possible implications of such a scenario. Our results also concludes that in 3+1 scheme, one can not have more than five-zeros in $m_{\nu }$.

   hep-phPRD(2017)·18 citations
8. 08*

   Neutrinophilic two Higgs doublet model with $U(1)$ global symmetry

   Kingman Cheung🇹🇼 · Hiroshi Okada🇹🇼 · Yuta Orikasa🇨🇿

   We propose a neutrinophilic two-Higgs-doublet model, where the vacuum expectation value (VEV) of the second Higgs doublet is only induced at one-loop level via several neutral fermions. Thus, the masses of active neutrinos arising from the Higgs doublets are naturally small via such a tiny VEV. We discuss various phenomenology of the model, including the neutrino masses and oscillations, bounds on non-unitarity, lepton-flavor violations, the oblique parameters, the muon anomalous magnetic moment, the GeV-scale sterile neutrino candidate arising from the tiny VEV, and collider signatures. We finally discuss the possibility of detecting the sterile neutrino suggested in the experiment of Future Circular Collider (FCC).

   hep-ph9 citations
9. 09*

   The Development of MPI Modelling in PYTHIA

   Torbjörn Sjöstrand🇸🇪

   Many of the basic ideas in multiparton interaction (MPI) phenomenology were first developed in the context of the PYTHIA event generator, and MPIs have been central in its modelling of both minimum-bias and underlying-event physics in one unified framework. This chapter traces the evolution towards an increasingly sophisticated description of MPIs in PYTHIA, including topics such as the ordering of MPIs, the regularization of the divergent QCD cross section, the impact-parameter picture, colour reconnection, multiparton PDFs and beam remnants, interleaved and intertwined evolution, and diffraction.

   hep-phAdv.Ser.Direct.High Energy Phys.(2018)·79 citations
10. 10*

    Higgs Factories: Higgs-Strahlung versus W-Fusion

    Remi Lafaye🇫🇷 · Tilman Plehn🇩🇪 · Michael Rauch🇩🇪 · Dirk Zerwas🇫🇷

    Higgs factories will be able to measure Higgs properties, and in particular Higgs couplings with high precision. In a follow-up to an earlier analysis we study the impact of the Higgs-strahlung and vector boson fusion processes on the precision of the couplings determination. Provided theoretical uncertainties can be controlled, future Higgs factories will be able to measure Higgs couplings at the sub-percent level. In spite of their different strengths, base-line circular and linear designs can expect a surprisingly similar performance.

    hep-phPRD(2017)·12 citations
11. 11*

    Locating the QCD critical end point through the peaked baryon number susceptibilities along the freeze-out line

    Zhibin Li🇨🇳 · Yidian Chen🇨🇳 · Danning Li🇨🇳 · Mei Huang🇨🇳

    We investigate the baryon number susceptibilities up to fourth order along different freeze-out lines in a holographic QCD model with the critical end point (CEP), and we propose that the peaked baryon number susceptibilities along the freeze-out line can be used as a clean signature to locate the CEP in the QCD phase diagram. On the temperature and baryon chemical potential plane, the ratio of the baryon number susceptibilities (up to fourth order) forms a ridge along the phase boundary, and develops a sword shape mountain standing upright around the CEP in a narrow and oblate region. This feature is model independent and universal if the CEP exists. The measurement of the baryon number susceptibilities from heavy-ion collision experiment is along the freeze-out line. If the freeze-out line crosses the foot of the CEP mountain, then one can observe the peaked baryon number susceptibilities along the freeze-out line, and the kurtosis of the baryon number distributions has the tallest magnitude. The data from the first phase of beam energy scan program at the Relativistic Heavy Ion Collisions indicates that a peak of the kurtosis of the baryon number distribution would show up at the collision energy around 5 GeV, which suggests that the freeze-out line crosses the foot of the CEP mountain and the summit of the CEP would be located nearby around the collision energy of 3 GeV.

    hep-phhep-lathep-thnucl-thCPC(2018)·44 citations
12. 12*

    Electron-deuteron deep-inelastic scattering with spectator nucleon tagging and final-state interactions at intermediate x

    M. Strikman🇺🇸 · C. Weiss🇺🇸

    We consider electron-deuteron deep-inelastic scattering (DIS) with detection of a proton in the nuclear fragmentation region ("spectator tagging") as a method for extracting the free neutron structure functions and studying their nuclear modifications. Such measurements could be performed at a future Electron-Ion Collider (EIC) with suitable forward detectors. The measured proton recoil momentum (~< 100 MeV in the deuteron rest frame) specifies the deuteron configuration during the high-energy process and permits a controlled theoretical treatment of nuclear effects. Nuclear and nucleonic structure are separated using methods of light-front quantum mechanics. The impulse approximation (IA) to the tagged DIS cross section contains the free neutron pole, which can be reached by on-shell extrapolation in the recoil momentum. Final-state interactions (FSI) distort the recoil momentum distribution away from the pole. In the intermediate-x region 0.1 < x < 0.5 FSI arise predominantly from interactions of the spectator proton with slow hadrons produced in the DIS process on the neutron (rest frame momenta ~< 1 GeV, target fragmentation region). We construct a schematic model describing this effect, using final-state hadron distributions measured in nucleon DIS experiments and low-energy hadron scattering amplitudes. We investigate the magnitude of FSI, their dependence on the recoil momentum (angular dependence, forward/backward regions), their analytic properties, and their effect on the on-shell extrapolation. We comment on the prospects for neutron structure extraction in tagged DIS with EIC. We discuss possible extensions of the FSI model to other kinematic regions (large/small x). In tagged DIS at x << 0.1 FSI resulting from diffractive scattering on the nucleons become important and require separate treatment.

    hep-phnucl-thPRC(2018)·23 citations
13. 13*

    DaMaSCUS: The Impact of Underground Scatterings on Direct Detection of Light Dark Matter

    Timon Emken🇩🇰 · Chris Kouvaris🇩🇰

    Conventional dark matter direct detection experiments set stringent constraints on dark matter by looking for elastic scattering events between dark matter particles and nuclei in underground detectors. However these constraints weaken significantly in the sub-GeV mass region, simply because light dark matter does not have enough energy to trigger detectors regardless of the dark matter-nucleon scattering cross section. Even if future experiments lower their energy thresholds, they will still be blind to parameter space where dark matter particles interact with nuclei strongly enough that they lose enough energy and become unable to cause a signal above the experimental threshold by the time they reach the underground detector. Therefore in case dark matter is in the sub-GeV region and strongly interacting, possible underground scatterings of dark matter with terrestrial nuclei must be taken into account because they affect significantly the recoil spectra and event rates, regardless of whether the experiment probes DM via DM-nucleus or DM-electron interaction. To quantify this effect we present the publicly available Dark Matter Simulation Code for Underground Scatterings (DaMaSCUS), a Monte Carlo simulator of DM trajectories through the Earth taking underground scatterings into account. Our simulation allows the precise calculation of the density and velocity distribution of dark matter at any detector of given depth and location on Earth. The simulation can also provide the accurate recoil spectrum in underground detectors as well as the phase and amplitude of the diurnal modulation caused by this shadowing effect of the Earth, ultimately relating the modulations expected in different detectors, which is important to decisively conclude if a diurnal modulation is due to dark matter or an irrelevant background.

    hep-phastro-ph.COJCAP(2017)·88 citations
14. 14*

    Zero-Range Effective Field Theory for Resonant Wino Dark Matter I. Framework

    Eric Braaten🇺🇸 · Evan Johnson🇺🇸 · Hong Zhang🇺🇸

    The most dramatic "Sommerfeld enhancements" of neutral-wino-pair annihilation occur when the wino mass is near a critical value where there is a zero-energy S-wave resonance at the neutral-wino-pair threshold. Near such a critical mass, low-energy winos can be described by a zero-range effective field theory in which the winos interact nonperturbatively through a contact interaction. The effective field theory is controlled by a renormalization-group fixed point at which the neutral and charged winos are degenerate in mass and their scattering length is infinite. The parameters of the zero-range effective field theory can be determined by matching wino-wino scattering amplitudes calculated by solving the Schrödinger equation for winos interacting through a potential due to the exchange of weak gauge bosons. If the wino mass is larger than the critical value, the resonance is a wino-pair bound state. The power of the zero-range effective field theory is illustrated by calculating the rate for formation of the bound state in the collision of two neutral winos through the emission of two soft photons.

    hep-phJHEP(2017)·25 citations
15. 15*

    Heavy neutrinos from gluon fusion

    Richard Ruiz🇬🇧 · Michael Spannowsky🇬🇧 · Philip Waite🇬🇧

    Heavy neutrinos, a key prediction of many standard model extensions, remain some of the most searched-for objects at collider experiments. In this context, we revisit the premise that the gluon fusion production mechanism, $gg\to Z^{\ast }/h^{\ast }\to N{\nu }_{\ell }$, is phenomenologically irrelevant at the CERN LHC and report the impact of soft gluon corrections to the production cross section. We resum threshold logarithms up to next-to-next-to-next-to-leading logarithmic accuracy (N${}^3$LL), thus capturing the dominant contributions to the inclusive cross section up to next-to-next-to-leading order (N${}^2$LO). For $m_N>150$ GeV and collider energies $\sqrt{s}=7-100$ TeV, corrections to the Born rates span $+160$ to $+260\%$. At $\sqrt{s}$=14 TeV, the resummed channel is roughly equal in size to the widely-believed-to-be-dominant charged current Drell-Yan process and overtakes it outright at $\sqrt{s}\gtrsim 20-25$ TeV. Results are independent of the precise nature/mixing of $N$ and hold generically for other low-scale seesaws. Findings are also expected to hold for other exotic leptons and broken axial-vector currents, particularly as the $Z^{\ast }$ contribution identically reduces to that of a pseudoscalar.

    hep-phhep-exPRD(2017)·40 citations
16. 16*

    Unification of gauge and Yukawa couplings

    Ammar Abdalgabar🇸🇩 · Mohammed Omer Khojali🇿🇦 · Alan S. Cornell🇿🇦 · Giacomo Cacciapaglia🇫🇷 · Aldo Deandrea🇫🇷

    The unification of gauge and top Yukawa couplings is an attractive feature of gauge-Higgs unification models in extra-dimensions. This feature is usually considered difficult to obtain based on simple group theory analyses. We reconsider a minimal toy model including the renormalisation group running at one loop. Our results show that the gauge couplings unify asymptotically at high energies, and that this may result from the presence of an UV fixed point. The Yukawa coupling in our toy model is enhanced at low energies, showing that a genuine unification of gauge and Yukawa couplings may be achieved.

    hep-phhep-thPLB(2018)·15 citations
17. 17*

    A model of spontaneous $CP$ breaking at low scale

    Gauhar Abbas🇮🇳

    We introduce a $CP$ symmetric model where masses of fermions are given by dimensional-5 operators, and $CP$ is spontaneously broken at TeV scale. The unique feature of the model is that new $CP$ symmetric gauge sector coexists with new $CP$ symmetric fermions simultaneously at TeV scale. An ultraviolet completion of the model is also proposed. It is observed that the fine-tuning of the SM Higgs boson mass in this model is softened in a relatively small amount approximately upto $6$ TeV. Other interesting consequences are presence of a possible dark matter candidate whose mass may be bounded from above by the SM Higgs mass. The model may also provide an explanation of recently observed flavour anomalies.

    hep-phPLB(2017)·19 citations
18. 18*

    Unifying static and dynamic properties in 3D quantum antiferromagnets

    H. D. Scammell🇦🇺 · Y. Kharkov🇦🇺 · Yan Qi Qin🇨🇳 · Zi Yang Meng🇨🇳 · B. Normand🇨🇭 · O. P. Sushkov🇦🇺

    Quantum Monte Carlo simulations offer an unbiased means to study the static and dynamic properties of quantum critical systems, while quantum field theory provides direct analytical results. We study three dimensional, critical quantum antiferromagnets by performing a combined analysis using both quantum field theory calculations and quantum Monte Carlo data. Explicitly, we analyze the order parameter (staggered magnetization), Néel temperature, quasiparticle gaps, and the susceptibilities in the scalar and vector channels. We connect the two approaches by deriving descriptions of the quantum Monte Carlo observables in terms of the quasiparticle excitations of the field theory. The remarkable agreement not only unifies the description of the static and dynamic properties of the system, but also constitutes a thorough test of perturbative O(3) quantum field theory and opens new avenues for the analytical guidance of detailed numerical studies.

    ↳ cond-mat.str-elcond-mat.stat-mechhep-phPRB(2017)·4 citations
19. 19*

    Prediction and detection potential of fusion neutrinos from nearby stars

    S. Arceo Diaz🇲🇽 · K. Zuber🇩🇪

    The shapes of neutrino spectra and fluxes from representative stars in the solar neighborhood up to 10 pc are calculated. The individual contribution of the most important, specific stellar objects (the alpha-Centauri system, Sirius A, Procyon, Vega, Fomalhaut and Altair) are determined and investigated by detailed stellar modeling. The possibility for a potential detection is discussed.

    ↳ astro-ph.SRhep-phnucl-ex0 citations
20. 20*

    Gravitational wave bursts from Primordial Black Hole hyperbolic encounters

    Juan Garcia-Bellido🇪🇸 · Savvas Nesseris🇪🇸

    We propose that Gravitational Wave (GW) bursts with millisecond durations can be explained by the GW emission from the hyperbolic encounters of Primordial Black Holes in dense clusters. These bursts are single events, with the bulk of the released energy happening during the closest approach, and emitted in frequencies within the AdvLIGO sensitivity range. We provide expressions for the shape of the GW emission in terms of the peak frequency and amplitude, and estimate the rates of these events for a variety of mass and velocity configurations. We study the regions of parameter space that will allow detection by both AdvLIGO and, in the future, LISA. We find for realistic configurations, with total mass $M\sim 60M_{\odot }$, relative velocities $v\sim 0.01c$, and impact parameters $b\sim 10^{-3}$ AU, for AdvLIGO an expected event rate is $\mathcal{O}(10)$ events/yr/Gpc${}^3$ with millisecond durations. For LISA, the typical duration is in the range of minutes to hours and the event-rate is $\mathcal{O}(10^3)$ events/yr/Gpc${}^3$ for both $10^3{M}_{\odot }$ IMBH and $10^6{M}_{\odot }$ SMBH encounters. We also study the distribution functions of eccentricities, peak frequencies and characteristic timescales that can be expected for a population of scattering PBH with a log-normal distribution in masses, different relative velocities and a flat prior on the impact parameter.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2017)·68 citations
21. 21*

    Analyzing H(z) Data using Two-point Diagnostics

    Kyle Leaf🇺🇸 · Fulvio Melia🇺🇸

    Measurements of the Hubble constant H(z) are increasingly being used to test the expansion rate predicted by various cosmological models. But the recent application of 2-point diagnostics, such as Om(z_i,z_j) and Omh^2(z_i,z_j), has produced considerable tension between LCDM's predictions and several observations, with other models faring even worse. Part of this problem is attributable to the continued mixing of truly model-independent measurements using the cosmic-chronomter approach, and model-dependent data extracted from BAOs. In this paper, we advance the use of 2-point diagnostics beyond their current status, and introduce new variations, which we call Delta h(z_i,z_j), that are more useful for model comparisons. But we restrict our analysis exclusively to cosmic-chronometer data, which are truly model independent. Even for these measurements, however, we confirm the conclusions drawn by earlier workers that the data have strongly non-Gaussian uncertainties, requiring the use of both "median" and "mean" statistical approaches. Our results reveal that previous analyses using 2-point diagnostics greatly underestimated the errors, thereby misinterpreting the level of tension between theoretical predictions and H(z) data. Instead, we demonstrate that as of today, only Einstein-de Sitter is ruled out by the 2-point diagnostics at a level of significance exceeding ~ 3 sigma. The R_h=ct universe is slightly favoured over the remaining models, including LCDM and Chevalier-Polarski-Linder, though all of them (other than Einstein-de Sitter) are consistent to within 1 sigma with the measured mean of the Delta h(z_i,z_j) diagnostics.

    ↳ astro-ph.COastro-ph.GAgr-qchep-ph+1MNRAS(2017)·18 citations
22. 22*

    Interacting neutrinos in cosmology: exact description and constraints

    Isabel M. Oldengott🇩🇪 · Thomas Tram🇩🇰 · Cornelius Rampf🇩🇪 · Yvonne Y. Y. Wong🇦🇺

    We consider the impact of neutrino self-interactions described by an effective four-fermion coupling on cosmological observations. Implementing the exact Boltzmann hierarchy for interacting neutrinos first derived in [arxiv:1409.1577] into the Boltzmann solver CLASS, we perform a detailed numerical analysis of the effects of the interaction on the cosmic microwave background (CMB) anisotropies, and compare our results with known approximations in the literature. While we find good agreement between our exact approach and the relaxation time approximation used in some recent studies, the popular $\left(c_{\text{eff}}^2,c_{\text{vis}}^2\right)$-parameterisation fails to reproduce the correct scale dependence of the CMB temperature power spectrum. We then proceed to derive constraints on the effective coupling constant $G_{\text{eff}}$ using currently available cosmological data via an MCMC analysis. Interestingly, our results reveal a bimodal posterior distribution, where one mode represents the standard $\Lambda$CDM limit with $G_{\mathrm{eff}}\lesssim 10^8{G}_{\mathrm{F}}$, and the other a scenario in which neutrinos self-interact with an effective coupling constant $G_{\mathrm{eff}}\simeq 3\times 10^9{G}_{\mathrm{F}}$.

    ↳ astro-ph.COhep-phJCAP(2017)·152 citations
23. 23*

    Quark matter revisited with non extensive MIT bag model

    Pedro H. G. Cardoso🇧🇷 · Tiago Nunes da Silva🇧🇷 · Airton Deppman🇧🇷 · Débora P. Menezes🇧🇷

    In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While, the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed.

    ↳ nucl-thastro-ph.HEcond-mat.stat-mechhep-phEPJA(2017)·46 citations
24. 24*

    Monte Carlo Tuning for $e^{+}{e}^{-}\to$ Hadrons and Comparison with Unfolded LEP Data

    Jennifer Kile🇵🇹 · Julian von Wimmersperg-Toeller🇵🇹

    We perform two tunes of the SHERPA Monte Carlo generator for the generation of $e^{+}{e}^{-}\to \text{mbox}hadrons$ using the publicly-available LEP analyses in Rivet. In each of these tunes, we generate events at $\sqrt{s}=91.25\text{mbox}GeV$ using matrix elements for final states containing up to six partons. In the first, "LO" tune, matrix elements for all final states are generated at leading order; in the second, "NLO" tune, matrix elements for final states with up to four partons are generated at next-to-leading order using BlackHat, while those for states with five and six partons are generated at leading order. The tunes are accomplished using Professor, and comparisons with unfolded LEP1 and LEP2 data are produced with Rivet. We also compare the data with events generated with KK2f interfaced to PYTHIA using the standard ALEPH tune. We find that both SHERPA samples show improvement relative to KK2f for observables related to four-jet final states, while all three samples produce comparable results for event-shape variables. Overall, the agreement with data is best for the LO tune. We provide our tuning parameters and many data-Monte Carlo comparisons.

    ↳ hep-exhep-ph9 citations
25. 25*

    Localized $4\sigma$ and $5\sigma$ Dijet Mass Excesses in ALEPH LEP2 Four-Jet Events

    Jennifer Kile🇵🇹 · Julian von Wimmersperg-Toeller🇵🇹

    We investigate an excess observed in hadronic events in the archived LEP2 ALEPH data. This excess was observed at preselection level during data-MC comparisons of four-jet events when no search was being performed. The events are clustered into four jets and paired such that the mass difference between the two dijet systems is minimized. The excess occurs in the region $M_1+M_2\sim 110\text{mbox}GeV$; about half of the excess is concentrated in the region $M_1\sim 80\text{mbox}GeV$, $M_2\sim 25\text{mbox}GeV$, with a local significance between $4.7\sigma$ and $5.5\sigma$, depending on assumptions about hadronization uncertainties. The other half of the events are in a broad excess near $M_1\sim M_2\sim 55\text{mbox}GeV$; these display a local significance of $4.1-4.5\sigma$. We investigate the effects of changing the SM QCD Monte Carlo sample, the jet-clustering algorithm, and the jet rescaling method. We find that the excess is remarkably robust under these changes, and we find no source of systematic uncertainty that can explain the excess. No analogue of the excess is seen at LEP1.

    ↳ hep-exhep-phJHEP(2018)·9 citations
26. 26*

    Simulation of $e^{+}{e}^{-}\to \text{mbox}Hadrons$ and Comparison to ALEPH Data at Full Detector Simulation with an Emphasis on Four-Jet States

    Jennifer Kile🇵🇹 · Julian von Wimmersperg-Toeller🇵🇹

    We use the SHERPA Monte Carlo generator to simulate the process $e^{+}{e}^{-}\to \text{mbox}hadrons$ using matrix elements with up to six partons in the final state. Two samples of SHERPA events are generated. In the "LO" sample, all final states are generated with leading order matrix elements; in the "NLO" sample, matrix elements for final states with up to four partons are generated at next-to-leading order, while matrix elements for final states with five or six partons are generated at leading order. The resulting samples are then passed through the ALEPH detector simulation. We compare the Monte Carlo samples to each other, to samples generated using the KK2f generator interfaced with PYTHIA, and to the archived ALEPH data at both LEP1 and LEP2 energies. We focus on four-jet observables with particular attention given to dijet masses. The LO and NLO SHERPA samples show significant improvement over the KK2f generation for observables directly related to clustering events into four jets, while maintaining similar performance to KK2f for event-shape variables. We additionally reweight the dijet masses using LEP1 data and find that this greatly improves the agreement between the three Monte Carlo samples at LEP2 energies for these observables.

    ↳ hep-exhep-ph8 citations
27. 27*

    On Algorithmic Universality in F-theory Compactifications

    James Halverson🇺🇸 · Cody Long🇺🇸 · Benjamin Sung🇺🇸

    We study universality of geometric gauge sectors in the string landscape in the context of F-theory compactifications. A finite time construction algorithm is presented for $\frac{4}{3}\times 2.96\times 10^{755}$ F-theory geometries that are connected by a network of topological transitions in a connected moduli space. High probability geometric assumptions uncover universal structures in the ensemble without explicitly constructing it. For example, non-Higgsable clusters of seven-branes with intricate gauge sectors occur with probability above $1-1.01\times 10^{-755}$, and the geometric gauge group rank is above $160$ with probability $.999995$. In the latter case there are at least $10$ $E_8$ factors, the structure of which fixes the gauge groups on certain nearby seven-branes. Visible sectors may arise from $E_6$ or $SU(3)$ seven-branes, which occur in certain random samples with probability $\simeq 1/200$.

    ↳ hep-thhep-phPRD(2017)·78 citations

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