Tue·Dec 12, 2017Tuesday·December 12, 2017

1. 01*

   SU(3) Polyakov linear-sigma model: Magnetic properties of QCD matter in thermal and dense medium

   Abdel Nasser Tawfik🇪🇬 · Abdel Magied Diab (Egyptian Ctr. Theor. Phys., Cairo and WLCAPP, Cairo)🇪🇬 · T. M. Hussein (Cairo U.)🇪🇬

   The linear-sigma model, in which information about confining gluons is included through the Polyakov-loop potential (PLSM), is considered in order to perform a systematic study for various magnetic properties of QCD matter under extreme conditions of high temperatures and densities and finite magnetic field strengths. The introduction of magnetic field to the PLSM Lagrangian requires suitable utilization of Landau quantization, modification in the dispersion relations, and momentum-space dimension-reduction. We observed that increasing the magnetic field leads to filling-up lower Landau levels first and decreasing the number of occupied levels. We conclude that the population of Landau levels is most sensitive to the magnetic field and to the quark charges. The influences of finite magnetic field on the temperature dependence of chiral and deconfinement order-parameter(s) are studied. We present estimations for the magnetization, the magnetic susceptibility, the permeability and the catalysis properties of QCD matter as functions of temperature. The dependences of the resulting freezeout parameters, temperatures and baryon chemical potentials on the corresponding magnetic field strengths have been analyzed, as well. These calculations are compared with recent lattice QCD simulations, whenever available. We conclude that the QCD matter seems to have paramagnetic property at temperatures greater than the critical one. There is an evidence for weak diamagnetic property at low temperatures. Last but not least, we observe that the magnetic catalysis is inverse, namely the critical temperatures decrease with increasing the magnetic field.

   hep-phhep-latnucl-thJ.Exp.Theor.Phys.(2018)·22 citations
2. 02*

   Reconstructing the invisible with matrix elements

   Danilo Enoque Ferreira de Lima🇩🇪 · Olivier Mattelaer🇧🇪 · Michael Spannowsky🇬🇧

   We propose a fully flexible method to perform an hypothesis test between signal and background based on the Matrix Element Method in the presence of multiple invisible particles. The proposed method performs a mapping of the measured final state onto its minimal hypersurface of degrees of freedom for a given process and then maximises the matrix element on this hypersurface separately for signal and background. To show how performant the method is in separating signal from background, we apply it to the prominent partly invisible decay of a Higgs boson into a muon-antimuon pair and two muon-neutrinos via two W bosons.

   hep-phPLB(2018)·11 citations
3. 03*

   Leptogenesis from Heavy Right-Handed Neutrinos in CPT Violating Backgrounds

   Thomas Bossingham🇬🇧 · Nick E. Mavromatos🇬🇧 · Sarben Sarkar🇬🇧

   We discuss leptogenesis in a model with heavy right-handed Majorana neutrinos propagating in a constant but otherwise generic CPT-violating axial time-like background (which could be motivated by string theory considerations). At temperatures much higher than the temperature of the electroweak phase transition we solve analytically but approximately (using Pade approximants) the corresponding Boltzmann equations, which describe lepton asymmetry generation due to the tree-level decays of the heavy neutrinos into standard model leptons. These leptons are effectively massless at such temperatures. The current work completes in a rigorous way a preliminary treatment of the same system, by some of the present authors. In this earlier work, lepton asymmetry was crudely estimated considering the decay of a right-handed neutrino at rest. Our present analysis includes thermal momentum modes for the heavy neutrino and this leads to a total lepton asymmetry which is bigger by a factor of two as compared to the previous estimate. Nevertheless, our current and preliminary results for the freezeout are found to be in agreement (within a 12.5% uncertainty). Our analysis depends on a novel use of Pade approximants to solve the Boltzmann equations and may be more widely useful in cosmology.

   hep-phgr-qchep-thEPJC(2018)·36 citations
4. 04*

   Singular lensing from the scattering on special space-time defects

   Nick E. Mavromatos🇬🇧 · Joannis Papavassiliou🇪🇸

   It is well known that certain special classes of self-gravitating point-like defects, such as global (non gauged) monopoles, give rise to non-asymptotically flat space-times characterized by solid angle deficits, whose size depends on the details of the underlying microscopic models. The scattering of electrically neutral particles on such space-times is described by amplitudes that exhibit resonant behaviour when the scattering and deficit angles coincide. This, in turn, leads to ring-like structures where the cross sections are formally divergent ("singular lensing"). In this work, we revisit this particular phenomenon, with the twofold purpose of placing it in a contemporary and more general context, in view of renewed interest in the theory and general phenomenology of such defects, and, more importantly, of addressing certain subtleties that appear in the particular computation that leads to the aforementioned effect. In particular, by adopting a specific regularization procedure for the formally infinite Legendre series encountered, we manage to ensure the recovery of the Minkowski space-time, and thus the disappearance of the lensing phenomenon, in the no-defect limit, and the validity of the optical theorem for the elastic total cross section. In addition, the singular nature of the phenomenon is confirmed by means of an alternative calculation, which, unlike the original approach, makes no use of the generating function of the Legendre polynomials, but rather exploits the asymptotic properties of the Fresnel integrals.

   hep-phgr-qchep-thEPJC(2018)·18 citations
5. 05*

   Minimal anomalous $\mathrm{U}(1)$ theories and collider phenomenology

   Andreas Ekstedt🇸🇪 · Rikard Enberg🇸🇪 · Gunnar Ingelman🇸🇪 · Johan Löfgren🇸🇪 · Tanumoy Mandal🇸🇪

   We study the collider phenomenology of a neutral gauge boson $Z^{\prime }$ arising in minimal but anomalous $\mathrm{U}(1)$ extensions of the Standard Model (SM). To retain gauge invariance of physical observables, we consider cancellation of gauge anomalies through the Green-Schwarz mechanism. We categorize a wide class of $\mathrm{U}(1)$ extensions in terms of the new $\mathrm{U}(1)$ charges of the left-handed quarks and leptons and the Higgs doublet. We derive constraints on some benchmark models using electroweak precision constraints and the latest 13 TeV LHC dilepton and dijet resonance search data. We calculate the decay rates of the exotic and rare one-loop $Z^{\prime }$ decays to $ZZ$ and $Z$-photon modes, which are the unique signatures of our framework. If observed, these decays could hint at anomaly cancellation through the Green-Schwarz mechanism. We also discuss the possible observation of such signatures at the LHC and at future ILC colliders.

   hep-phJHEP(2018)·14 citations
6. 06*

   Heavy Quark Spin Symmetry Violating Hadronic Transitions of Higher Charmonia

   Muhammad Naeem Anwar🇨🇳 · Yu Lu🇩🇪 · Bing-Song Zou🇨🇳

   In heavy quarkonia, hadronic transitions serve as an enlightened probe for the structure and help to establish the understanding of light quark coupling with a heavy degree of freedom. Moreover, in recent years, hadronic transitions revealed remarkable discoveries to identify the new conventional heavy quarkonia and extracting useful information about the so called "XYZ" exotic states. In this contribution, we present our predictions for heavy quark spin symmetry (HQSS) breaking hadronic transitions of higher $S$ and $D$ wave vector charmonia based on our recently proposed model (inspired by Nambu-Jona-Lasinio (NJL) model) to create light meson(s) in heavy quarkonium transitions. We also suggest spectroscopic quantum numbers ${(}^{2S+1}{L}_J)$ for several observed charmoniumlike states. Our analysis indicates that the $Y(4360)$ is most likely to be a $3D$ dominant state.

   hep-phhep-exnucl-thPoS(2018)·3 citations
7. 07*

   Predicting and Discovering True Muonium

   Henry Lamm🇺🇸 · Yao Ji🇩🇪

   The recent observation of discrepancies in the muonic sector motivates searches for the yet undiscovered atom true muonium $({\mu }^{+}{\mu }^{-})$. To leverage potential experimental signals, precise theoretical calculations are required. I will present the on-going work to compute higher-order corrections to the hyperfine splitting and the Lamb shift. Further, possible detection in rare meson decay experiments like REDTOP and using true muonium production to constrain mesonic form factors will be discussed.

   hep-phphysics.atom-phEPJ Web Conf.(2018)·15 citations
8. 08*

   Frame dependence of form factors in light-front dynamics

   Yang Li🇺🇸 · Pieter Maris🇺🇸 · James Vary🇺🇸

   In light-front dynamics, form factors are traditionally computed with the "good current" $J^{+}$ within the Drell-Yan frame $q^{+}=0$. Due to truncations imposed in practical calculations, the from factor may acquire frame dependence, which is often neglected. In this work, we explore the form factors in more general frames, preserving the boost covariance. We find the frame dependence of the elastic form factors for mesons is small in basis light-front holography and related models with two-body Fock space truncation. We suggest to use the difference between form factor results from Drell-Yan frame and the "longitudinal frame" as a metric for the violation of the Lorentz symmetry due to Fock space truncation.

   hep-phnucl-thPRD(2018)·27 citations
9. 09*

   Gravitation waves from QCD and electroweak phase transitions

   Yidian Chen🇨🇳 · Mei Huang🇨🇳 · Qi-Shu Yan🇨🇳

   We investigate the gravitation waves produced from QCD and electroweak phase transitions in the early universe by using a 5-dimension holographic QCD model and a holographic technicolor model. The dynamical holographic QCD model is to describe the pure gluon system, where a first order confinement-deconfinement phase transition can happen at the critical temperature around 250 $\mathrm{MeV}$. The minimal holographic technicolor model is introduced to model the strong dynamics of electroweak, it can give a first order electroweak phase transition at the critical temperature around 100-360 $\mathrm{GeV}$. We find that for both GW signals produced from QCD and EW phase transitions, in the peak frequency region, the dominant contribution comes from the sound waves, while away from the peak frequency region the contribution from the bubble collision is dominant. The peak frequency of gravitation wave determined by the QCD phase transition is located around $10^{-7}$ Hz which is within the detectability of FAST and SKA, and the peak frequency of gravitational wave predicted by EW phase transition is located at $0.002-0.007$ Hz, which might be detectable by BBO, DECIGO, LISA and ELISA.

   hep-phJHEP(2018)·54 citations
10. 10*

    Searches for anomalous $tqZ$ couplings from the trilepton signal of $tZ$ associated production at the 14 TeV LHC

    Jie-Fen Shen🇨🇳 · Yu-Qi Li🇨🇳 · Yao-Bei Liu🇨🇳

    We investigate the observability of the top anomalous $tqZ$ couplings via the trilepton signatures at the Large Hadron Collider~(LHC) with the center-of-mass energy of 14 TeV. We focus on signals of the $tZ$ associated production with the decay mode $t\to W^{+}b\to b{\ell }^{+}{\nu }_{\ell }$, $Z\to {\ell }^{+}{\ell }^{-}$, and $t\bar{t}$ production with the decay mode $\bar{t}\to Z(\to {\ell }^{+}{\ell }^{-})\bar{q}$ and $t\to b{\ell }^{+}{\nu }_{\ell }$, where $\ell =e,\mu$ and $q$ reflects up and charm quarks. It is shown that at $3\sigma$ level, the FCNC top quark decay branching ratios can be probed at, respectively, about $Br(t\to uZ)\le 1.3\times 10^{-4}$ and $Br(t\to cZ)\le 4.2\times 10^{-4}$ with the integrated luminosity of 100 fb${}^{-1}$, and probed down to $Br(t\to uZ)\le 2.2\times 10^{-5}$ and $Br(t\to cZ)\le 8\times 10^{-5}$ for the high-luminosity LHC with 3000 fb${}^{-1}$.

    hep-phPLB(2018)·17 citations
11. 11*

    Two-Loop integrals for CP-even heavy quarkonium production and decays: Elliptic Sectors

    Long-Bin Chen🇨🇳 · Jun Jiang🇨🇳 · Cong-Feng Qiao🇨🇳

    By employing the differential equations, we compute analytically the elliptic sectors of two-loop master integrals appearing in the NNLO QCD corrections to CP-even heavy quarkonium exclusive production and decays, which turns out to be the last and toughest part in the relevant calculation. The integrals are found can be expressed as Goncharov polylogarithms and iterative integrals over elliptic functions. The master integrals may be applied to some other NNLO QCD calculations about heavy quarkonium exclusive production, like ${\gamma }^{\ast }\gamma \to Q\bar{Q}$, $e^{+}{e}^{-}\to \gamma +Q\bar{Q}$,~and~$H/Z^0\to \gamma +Q\bar{Q}$, heavy quarkonium exclusive decays, and also the CP-even heavy quarkonium inclusive production and decays.

    hep-phJHEP(2018)·26 citations
12. 12*

    Mass scale of vectorlike matter and superpartners from IR fixed point predictions of gauge and top Yukawa couplings

    Radovan Dermisek🇺🇸 · Navin McGinnis🇺🇸

    We use the IR fixed point predictions for gauge couplings and the top Yukawa coupling in the MSSM extended with vectorlike families to infer the scale of vectorlike matter and superpartners. We quote results for several extensions of the MSSM and present results in detail for the MSSM extended with one complete vectorlike family. We find that for a unified gauge coupling ${\alpha }_G>0.3$ vectorlike matter or superpartners are expected within 1.7 TeV (2.5 TeV) based on all three gauge couplings being simultaneously within 1.5\% (5\%) from observed values. This range extends to about 4 TeV for ${\alpha }_G>0.2$. We also find that in the scenario with two additional large Yukawa couplings of vectorlike quarks the IR fixed point value of the top Yukawa coupling independently points to a multi-TeV range for vectorlike matter and superpartners. Assuming a universal value for all large Yukawa couplings at the GUT scale, the measured top quark mass can be obtained from the IR fixed point for $\tan \beta \simeq 4$. The range expands to any $\tan \beta >3$ for significant departures from the universality assumption. Considering that the Higgs boson mass also points to a multi-TeV range for superpartners in the MSSM, adding a complete vectorlike family at the same scale provides a compelling scenario where the values of gauge couplings and the top quark mass are understood as a consequence of the particle content of the model.

    hep-phPRD(2018)·14 citations
13. 13*

    Differential equations for Feynman integrals beyond multiple polylogarithms

    Luise Adams🇩🇪 · Christian Bogner🇩🇪 · Ekta Chaubey🇩🇪 · Armin Schweitzer🇨🇭 · Stefan Weinzierl🇩🇪

    Differential equations are a powerful tool to tackle Feynman integrals. In this talk we discuss recent progress, where the method of differential equations has been applied to Feynman integrals which are not expressible in terms of multiple polylogarithms.

    hep-phhep-thPoS(2017)·4 citations
14. 14*

    Constraints on neutrino masses from Baryon Acoustic Oscillation measurements

    B. Hoeneisen🇪🇨

    From 21 independent Baryon Acoustic Oscillation (BAO) measurements we obtain the following sum of masses of active Dirac or Majorana neutrinos: $\sum m_{\nu }=0.711-0.335\cdot \delta h+0.050\cdot \delta b\pm 0.063\text{ eV,}$ where $\delta h\equiv (h-0.678)/0.009$ and $\delta b\equiv ({\Omega }_b{h}^2-0.02226)/0.00023$. This result may be combined with independent measurements that constrain the parameters $\sum m_{\nu }$, $h$, and ${\Omega }_b{h}^2$. For $\delta h=\pm 1$ and $\delta b=\pm 1$, we obtain $m_{\nu }<0.43$ eV at 95\% confidence.

    hep-ph0 citations
15. 15*

    A suggested search for doubly charmed baryons of $J^P=3/2^{+}$ via their electromagnetic transitions

    Er-Liang Cui🇨🇳 · Hua-Xing Chen🇨🇳 · Wei Chen🇨🇳 · Xiang Liu🇨🇳 · Shi-Lin Zhu🇨🇳

    We use the method of light-cone sum rules to study the electromagnetic transition of the ${\Xi }_{cc}^{\ast ++}$ into ${\Xi }_{cc}^{++}\gamma$, whose decay width is estimated to be $13.7{}_{-7.9}^{+17.7}$ keV. This value is large enough for the ${\Xi }_{cc}^{\ast ++}$ to be observed in the ${\Xi }_{cc}^{++}\gamma$ channel, and we propose to continually search for it in future LHCb and BelleII experiments.

    hep-phhep-exPRD(2018)·25 citations
16. 16*

    Quark jet versus gluon jet: fully-connected neural networks with high-level features

    Hui Luo🇩🇪 · Ming-xing Luo🇨🇳 · Kai Wang🇨🇳 · Tao Xu🇨🇳 · Guohuai Zhu🇨🇳

    Jet identification is one of the fields in high energy physics that machine learning has begun to make an impact. More often than not, convolutional neural networks are used to classify jet images with the benefit that essentially no physics input is required. Inspired by a recent work by Datta and Larkoski, we study the classification of quark/gluon-initiated jets based on fully-connected neural networks (FNNs), where expert-designed physical variables are taken as input. FNNs are applied in two ways: trained separately on various narrow jet transverse momentum $p_{TJ}$ bins; trained on a wide region of $p_{TJ}\in [200,1000]$ GeV. We find their performances are almost the same. The performance is better when the $p_{TJ}$ is larger. Jet discrimination with FNN is studied on both particle and detector level data. The results based on particle level data are comparable with those from deep convolutional neural networks, while the significance improvement characteristic (SIC) from detector level data would at most decrease by $15\%$. We also test the performance of FNNs with full set or subsets of jet observables as input features. The FNN with one subset consisting of fourteen observables shows nearly no degradation of performance. This indicates that these fourteen expert-designed observables could have captured the most necessary information for separating quark and gluon jets.

    hep-phhep-exSCPMA(2019)·38 citations
17. 17*

    Prospects of type-II seesaw at future colliders in light of the DAMPE $e^{+}{e}^{-}$ excess

    Yicong Sui🇺🇸 · Yongchao Zhang🇺🇸

    The DAMPE $e^{+}{e}^{-}$ excess at around 1.4 TeV could be explained in the type-II seesaw model with a scalar dark mater $D$ which is stabilized by a discrete $Z_2$ symmetry. The simplest scenario is the annihilation $DD\to H^{++}{H}^{--}$ followed by the subsequent decay $H^{\pm \pm }\to e^{\pm }{e}^{\pm }$, with both the DM and triplet scalars roughly 3 TeV with a small mass splitting. In addition to the Drell-Yan process at future 100 TeV hadron colliders, the doubly-charged components could also be produced at lepton colliders like ILC and CLIC in the off-shell mode, and mediate lepton flavor violating processes $e^{+}{e}^{-}\to {\ell }_i^{\pm }{\ell }_j^{\mp }$ (with $i\ne j$). A wide range of parameter space of the type-II seesaw could be probed, which are well below the current stringent lepton flavor constraints.

    hep-phastro-ph.COhep-exPRD(2018)·30 citations
18. 18*

    DAMPE excess from decaying right-handed neutrino dark matter

    Nobuchika Okada🇺🇸 · Osamu Seto🇯🇵

    The flux of high-energy cosmic-ray electrons plus positrons recently measured by the DArk Matter Particle Explorer (DAMPE) exhibits a tentative peak excess at an energy of around $1.4$ TeV. In this paper, we consider the minimal gauged $U(1{)}_{B-L}$ model with a right-handed neutrino (RHN) dark matter (DM) and interpret the DAMPE peak with a late-time decay of the RHN DM into $e^{\pm }{W}^{\mp }$. We find that a DM lifetime ${\tau }_{DM}\sim 10^{28}$ s can fit the DAMPE peak with a DM mass $m_{DM}=3$ TeV. This favored lifetime is close to the current bound on it by Fermi-LAT, our decaying RHN DM can be tested once the measurement of cosmic gamma ray flux is improved. The RHN DM communicates with the Standard Model particles through the $U(1{)}_{B-L}$ gauge boson ($Z^{\prime }$ boson), and its thermal relic abundance is controlled by only three free parameters: $m_{DM}$, the $U(1{)}_{B-L}$ gauge coupling (${\alpha }_{BL}$), and the $Z^{\prime }$ boson mass ($m_{Z^{\prime }}$). For $m_{DM}=3$ TeV, the rest of the parameters are restricted to be $m_{Z^{\prime }}\simeq 6$ TeV and $0.00807\le {\alpha }_{BL}\le 0.0149$, in order to reproduce the observed DM relic density and to avoid the Landau pole for the running ${\alpha }_{BL}$ below the Planck scale. This allowed region will be tested by the search for a $Z^{\prime }$ boson resonance at the future Large Hadron Collider.

    hep-phastro-ph.HEMod.Phys.Lett.A(2018)·26 citations
19. 19*

    Sneutrinos as Mixed Inflaton and Curvaton

    Naoyuki Haba🇯🇵 · Tomo Takahashi🇯🇵 · Toshifumi Yamada🇯🇵

    We investigate a scenario where the supersymmetric partners of two right-handed neutrinos (sneutrinos) work as mixed inflaton and curvaton, motivated by the fact that the curvaton contribution to scalar perturbations can reduce the tensor-to-scalar ratio $r$ so that chaotic inflation models with a quadratic potential are made consistent with the experimental bound on $r$. After confirming that the scenario evades the current bounds on $r$ and the scalar perturbation spectral index $n_s$, we make a prediction on the local non-Gaussianity in bispectrum, $f_{\mathrm{NL}}$, and one in trispectrum, ${\tau }_{\mathrm{NL}}$. Remarkably, since the sneutrino decay widths are determined by the neutrino Dirac Yukawa coupling, which can be estimated from the measured active neutrino mass differences in the seesaw model, our scenario has a strong predictive power about local non-Gaussianities, as they heavily depend on the inflaton and curvaton decay rates. Using this fact, we can constrain the sneutrino mass from the experimental bounds on $n_s$, $r$ and $f_{\mathrm{NL}}$.

    hep-phJCAP(2018)·7 citations
20. 20*

    RG analysis at higher orders in perturbative QFTs in CMP

    Nikolai Zerf🇩🇪

    In this contribution we report on the perturbative determination of $\beta$-functions and anomalous dimensions for the chiral Ising, chiral XY and chiral Heisenberg Gross-Neveu-Yukawa model around $D=4$ dimensions at four loops and the first Padé extrapolation of critical exponents at non-trivial, infrared stable fixed points to $D=3$ to this order. This talk is based on Ref. [Zerf:2017zqi].

    hep-phPoS(2017)·0 citations
21. 21*

    Gluino two-body decays at full one-loop level in the MSSM with quark-flavour violation

    Helmut Eberl🇦🇹 · Elena Ginina🇦🇹 · Keisho Hidaka🇯🇵

    We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalization is done in the DRbar scheme and hard gluon and photon radiations are included by adding the corresponding three-body decay widths. In the numerics the dependence of the gluino decay widths on the QFV parameters is discussed with special emphasis put on the separation of the electroweak and the SUSY QCD corrections. The main dependence stems from the ${\tilde{c}}_R-{\tilde{t}}_R$ mixing in the decays to up-type squarks because there hold strong constraints from B-physics on the other quark-flavour mixing parameters. Including the full one-loop corrections, the changes of the gluino decay widths are mostly negative and of the order of about -10%. The QFV part stays small in the total width but can vary up to -8% for the decay width into the lightest squark. For the corresponding branching ratio, however, the effect is smaller by at least a factor of two. The electroweak corrections can become 35% of the SUSY QCD corrections.

    hep-phPoS(2017)·0 citations
22. 22*

    The QCD Phase Diagram from Statistical Model Analysis

    Francesco Becattini · Marcus Bleicher · Jan Steinheimer · Reinhard Stock

    Ideally, the Statistical Hadronization Model (SHM) freeze-out curve should reveal the QCD parton-hadron phase transformation line in the ($T$,${\mu }_B$) plane. We discuss the effects of various final state interaction phenomena, like baryon-antibaryon annihilation, core-corona effects or QCD critical point formation, which shift or deform the SHM freezeout curve. In particular, we present a method to remove the annihilation effects by quantifying them with the microscopic hadron transport model UrQMD. We further discuss the new aspects of hadronization that could be associated with the relatively broad cross-over phase transformation as predicted by lattice-QCD theory at low ${\mu }_B$. That opens up the possibility that various observables of hadronization, e.g. hadron formation or susceptibilities of higher order (related to grand canonical fluctuations of conserved hadronic charges) may freeze out at different characteristic temperatures. This puts into question the concept of a universal \textit{(pseudo-)critical} temperature, as does the very nature of a cross-over phase transformation.

    hep-phnucl-th7 citations
23. 23*

    The Higgs Boson can delay Reheating after Inflation

    Katherine Freese🇸🇪 · Evangelos I. Sfakianakis🇳🇱 · Patrick Stengel🇸🇪 · Luca Visinelli🇸🇪

    The Standard Model Higgs boson, which has previously been shown to develop an effective vacuum expectation value during inflation, can give rise to large particle masses during inflation and reheating, leading to temporary blocking of the reheating process and a lower reheat temperature after inflation. We study the effects on the multiple stages of reheating: resonant particle production (preheating) as well as perturbative decays from coherent oscillations of the inflaton field. Specifically, we study both the cases of the inflaton coupling to Standard Model fermions through Yukawa interactions as well as to Abelian gauge fields through a Chern-Simons term. We find that, in the case of perturbative inflaton decay to SM fermions, reheating can be delayed due to Higgs blocking and the reheat temperature can decrease by up to an order of magnitude. In the case of gauge-reheating, Higgs-generated masses of the gauge fields can suppress preheating even for large inflaton-gauge couplings. In extreme cases, preheating can be shut down completely and must be substituted by perturbative decay as the dominant reheating channel. Finally, we discuss the distribution of reheat temperatures in different Hubble patches, arising from the stochastic nature of the Higgs VEV during inflation and its implications for the generation of both adiabatic and isocurvature fluctuations.

    hep-phastro-ph.COJCAP(2018)·48 citations
24. 24*

    Testing Dark Matter Models with Radio Telescopes in light of Gravitational Wave Astronomy

    Andrea Addazi🇨🇳 · Yi-Fu Cai🇨🇳 · Antonino Marciano🇨🇳

    In this Letter we put forward a novel phenomenological paradigm in which particle physics beyond the Standard Model may be tested by radio astronomy if they are related to a first order phase transition in the early Universe. For this type of Dark Matter models, the first order phase transition takes place at KeV scales, and hence, induces the production of a stochastic gravitational wave background that can be detected from Pulsar timing measures. We demonstrate this hypothetical feasibility by studying a class of Majoron Dark Matter model, which is related to a first order phase transition of the $U(1{)}_L$ or $U(1{)}_{B-L}$ symmetry and is consequently dubbed as {\it violent Majoron}. This phenomenon are expected to be examined by the ongoing and forthcoming radio experiments, including FAST, SKA and IPTA.

    hep-phastro-ph.HEgr-qcPLB(2018)·21 citations
25. 25*

    Electrical and thermal conductivities of hot and dense hadron gas

    Guruprasad Kadam🇮🇳 · Hiranmaya Mishra🇮🇳 · Lata Thakur🇮🇳

    We estimate the electrical and thermal conductivities of hot and dense hadronic matter in the relaxation time approximation of the Boltzmann equation. We estimate the thermodynamical quantities of hot and dense hadronic matter within the ambit of the excluded volume hadron resonance gas model. The relaxation time for all the hadrons is estimated assuming the constant cross section with uniform as well as mass dependent hard-core radius. We compare our results with various existing results. Finally we give an estimate of electrical and thermal conductivities in the context of heavy ion collision experiments.

    hep-phnucl-thPRD(2018)·36 citations
26. 26*

    Dark Matter as Ultralight Axion-Like particle in $E_6\times U(1{)}_X$ GUT with QCD Axion

    Claudio Coriano🇮🇹 · Paul H. Frampton🇮🇹

    Axion-like fields are naturally generated by a mechanism of anomaly cancellation of one or more anomalous gauge abelian symmetries at the Planck scale, emerging as duals of a two-form from the massless bosonic sector of string theory. This suggests an analogy of the Green-Schwarz mechanism of anomaly cancellation, at field theory level, which results in one or more Stueckelberg pseudoscalars. In the case of a single Stueckelberg pseudoscalar $b$, vacuum misalignments at phase transitions in the early Universe at the GUT scale provide a small mass - due to instanton suppression of the periodic potential - for a component of $b$, denoted as $\chi$ and termed the "axi-Higgs", which is a physical axion-like particle. The coupling of the axi-Higgs to the gauge sector via Wess-Zumino terms is suppressed by the Planck mass, which guarantees its decoupling, while its angle of misalignment is related to $M_{GUT}$. We build a gauged $E_6\times U(1)$ model with anomalous $U(1)$. It contains both an automatic invisible QCD axion and an ultra-light axi-Higgs. The invisible axion present in the model solves the strong CP problem and has mass in the conventional range while the axi-Higgs, which can act as dark matter, is sufficiently light ($10^{-22}\text{ eV}<m_{\chi }<10^{-20}\text{ eV}$) to solve short-distance problems which confront other cold dark matter candidates.

    hep-phastro-ph.COhep-thPLB(2018)·8 citations
27. 27*

    Dark matter production in association with a single top-quark at the LHC in a two-Higgs-doublet model with a pseudoscalar mediator

    Priscilla Pani🇨🇭 · Giacomo Polesello🇮🇹

    The sensitivity of the LHC experiments to the associated production of dark matter with a single top is studied in the framework of an extension of the standard model featuring two Higgs doublets and an additional pseudoscalar mediator. It is found that the experimental sensitivity is dominated by the on-shell production of a charged Higgs boson, when this assumes a mass below 1 TeV. Dedicated selections considering one and two lepton final states are developed to assess the coverage in parameter space for this signature at a centre-of-mass energy of 14 TeV assuming an integrated luminosity of 300 fb${}^{-1}$. For a pseudoscalar mediator with mass 150 GeV and maximally mixed with the pseudoscalar of the two Higgs doublets, values of $tan\beta$ up to 3 and down to 15 can be excluded at 95% CL, if the $H^{\pm }$ mass is in the range 300 GeV-1 TeV. This novel signature complements the parameter space coverage of the mono-Higgs, mono-Z and $t\bar{t}$+$E_{\mathrm{T}}^{\mathrm{m}iss}$ signatures considered in previous publications for this model.

    hep-phPhys.Dark Univ.(2018)·58 citations
28. 28*

    Sum rules across the unpolarized Compton processes involving generalized polarizabilities and moments of nucleon structure functions

    Vadim Lensky🇩🇪 · Franziska Hagelstein🇨🇭 · Vladimir Pascalutsa🇩🇪 · Marc Vanderhaeghen🇩🇪

    We derive two new sum rules for the unpolarized doubly virtual Compton scattering process on a nucleon, which establish novel low-$Q^2$ relations involving the nucleon's generalized polarizabilities and moments of the nucleon's unpolarized structure functions $F_1(x,Q^2)$ and $F_2(x,Q^2)$. These relations facilitate the determination of some structure constants which can only be accessed in off-forward doubly virtual Compton scattering, not experimentally accessible at present. We perform an empirical determination for the proton and compare our results with a next-to-leading-order chiral perturbation theory prediction. We also show how these relations may be useful for a model-independent determination of the low-$Q^2$ subtraction function in the Compton amplitude, which enters the two-photon-exchange contribution to the Lamb shift of (muonic) hydrogen. An explicit calculation of the $\Delta (1232)$-resonance contribution to the muonic-hydrogen $2P-2S$ Lamb shift yields $-1\pm 1$ $\mu$eV, confirming the previously conjectured smallness of this effect.

    hep-phnucl-exnucl-thPRD(2018)·25 citations
29. 29*

    Planar Two-Loop Five-Gluon Amplitudes from Numerical Unitarity

    Samuel Abreu🇩🇪 · Fernando Febres Cordero🇩🇪 · Harald Ita🇩🇪 · Ben Page🇩🇪 · Mao Zeng🇺🇸

    We present a calculation of the planar two-loop five-gluon amplitudes. The amplitudes are obtained in a variant of the generalized unitarity approach suitable for numerical computations, which we extend for use with finite field arithmetics. Employing a new method for the generation of unitarity-compatible integration-by-parts identities, all helicity amplitudes are reduced to a linear combination of master integrals for the first time. The approach allows us to compute exact values for the integral coefficients at rational phase-space points. All required master integrals are known analytically, and we obtain arbitrary-precision values for the amplitudes.

    hep-phhep-thPRD(2018)·158 citations
30. 30*

    Dynamic Freeze-In: Impact of Thermal Masses and Cosmological Phase Transitions on Dark Matter Production

    Michael J. Baker🇨🇭 · Moritz Breitbach🇩🇪 · Joachim Kopp🇩🇪 · Lukas Mittnacht🇩🇪

    The cosmological abundance of dark matter can be significantly influenced by the temperature dependence of particle masses and vacuum expectation values. We illustrate this point in three simple freeze-in models. The first one, which we call kinematically induced freeze-in, is based on the observation that the effective mass of a scalar temporarily becomes very small as the scalar potential undergoes a second order phase transition. This opens dark matter production channels that are otherwise forbidden. The second model we consider, dubbed vev-induced freeze-in, is a fermionic Higgs portal scenario. Its scalar sector is augmented compared to the Standard Model by an additional scalar singlet, $S$, which couples to dark matter and temporarily acquires a vacuum expectation value (a two-step phase transition or `vev flip-flop'). While $⟨S⟩\ne 0$, the modified coupling structure in the scalar sector implies that dark matter production is significantly enhanced compared to the $⟨S⟩=0$ phases realised at very early times and again today. The third model, which we call mixing-induced freeze-in, is similar in spirit, but here it is the mixing of dark sector fermions, induced by non-zero $⟨S⟩$, that temporarily boosts the dark matter production rate. For all three scenarios, we carefully dissect the evolution of the dark sector in the early Universe. We compute the DM relic abundance as a function of the model parameters, emphasising the importance of thermal corrections and the proper treatment of phase transitions in the calculation.

    hep-phastro-ph.COJHEP(2018)·82 citations
31. 31*

    BBN constraints on MeV-scale dark sectors. Part I. Sterile decays

    Marco Hufnagel🇩🇪 · Kai Schmidt-Hoberg🇩🇪 · Sebastian Wild🇩🇪

    We study constraints from Big Bang Nucleosynthesis on inert particles in a dark sector which contribute to the Hubble rate and therefore change the predictions of the primordial nuclear abundances. We pay special attention to the case of MeV-scale particles decaying into dark radiation, which are neither fully relativistic nor non-relativistic during all temperatures relevant to Big Bang Nucleosynthesis. As an application we discuss the implications of our general results for models of self-interacting dark matter with light mediators.

    hep-phastro-ph.COJCAP(2018)·80 citations
32. 32*

    Tagging Jets in Invisible Higgs Searches

    Anke Biekötter🇩🇪 · Fabian Keilbach🇩🇪 · Rhea Moutafis🇩🇪 · Tilman Plehn🇩🇪 · Jennifer M. Thompson🇩🇪

    Searches for invisible Higgs decays in weak boson fusion are a well-known laboratory for jets and QCD studies. We present a series of results on tagging jets and central jet activity. First, precision analyses of the central jet activity require full control of single top production in some analyses. Second, the rate dependence on the size of the tagging jets is not limited to weak boson fusion. For the first time, we show how subjet information on the tagging jets and on the additional jet activity can be used to extract the Higgs signal. The additional observables relieve some of the pressure on other, critical observables. Finally, we compare the performance of weak boson fusion and associated Higgs production.

    hep-phSciPost Phys.(2018)·14 citations
33. 33*

    Looking for the WIMP Next Door

    Jared A. Evans🇺🇸 · Stefania Gori🇺🇸 · Jessie Shelton🇺🇸

    We comprehensively study experimental constraints and prospects for a class of minimal hidden sector dark matter (DM) models, highlighting how the cosmological history of these models informs the experimental signals. We study simple "secluded" models, where the DM freezes out into unstable dark mediator states, and consider the minimal cosmic history of this dark sector, where coupling of the dark mediator to the SM was sufficient to keep the two sectors in thermal equilibrium at early times. In the well-motivated case where the dark mediators couple to the Standard Model (SM) via renormalizable interactions, the requirement of thermal equilibrium provides a minimal, UV-insensitive, and predictive cosmology for hidden sector dark matter. We call DM that freezes out of a dark radiation bath in thermal equilibrium with the SM a WIMP next door, and demonstrate that the parameter space for such WIMPs next door is sharply defined, bounded, and in large part potentially accessible. This parameter space, and the corresponding signals, depend on the leading interaction between the SM and the dark mediator; we establish it for both Higgs and vector portal interactions. In particular, there is a cosmological lower bound on the portal coupling strength necessary to thermalize the two sectors in the early universe. We determine this thermalization floor as a function of equilibration temperature for the first time. We demonstrate that direct detection experiments are currently probing this cosmological lower bound in some regions of parameter space, while indirect detection signals and terrestrial searches for the mediator cut further into the viable parameter space. We present regions of interest for both direct detection and dark mediator searches, including motivated parameter space for the direct detection of sub-GeV DM.

    hep-phJHEP(2018)·122 citations
34. 34*

    Neutrino oscillation processes with a change of lepton flavor in quantum field-theoretical approach

    Vadim O. Egorov🇷🇺 · Igor P. Volobuev🇷🇺

    The oscillating probabilities of lepton flavor changing neutrino oscillation processes, where neutrinos are detected by charged-current and neutral-current interactions, are calculated in a quantum field-theoretical approach to neutrino oscillations based on a modification of the Feynman propagator in the momentum reprsentation. The approach is most similar to the standard Feynman diagram technique in the momentum representation. It is found that the oscillating distance-dependent probabilities of detecting an electron in experiments with neutrino production in the muonic decay of ${\pi }^{+}$-meson and the detection of the produced neutrino by charged-current and neutral-current interactions exactly coincide with the corresponding probabilities calculated in the standard approach.

    hep-phJ.Exp.Theor.Phys.(2019)·8 citations
35. 35*

    A Subleading Power Operator Basis for the Scalar Quark Current

    Cyuan-Han Chang🇺🇸 · Iain W. Stewart🇺🇸 · Gherardo Vita🇺🇸

    Factorization theorems play a crucial role in our understanding of the strong interaction. For collider processes they are typically formulated at leading power and much less is known about power corrections in the $\lambda \ll 1$ expansion. Here we present a complete basis of power suppressed operators for a scalar quark current at $\mathcal{O}({\lambda }^2)$ in the amplitude level power expansion in the Soft Collinear Effective Theory, demonstrating that helicity selection rules significantly simplify the construction. This basis applies for the production of any color singlet scalar in $q\bar{q}$ annihilation (such as $b\bar{b}\to H$). We also classify all operators which contribute to the cross section at $\mathcal{O}({\lambda }^2)$ and perform matching calculations to determine their tree level Wilson coefficients. These results can be exploited to study power corrections in both resummed and fixed order perturbation theory, and for analyzing the factorization properties of gauge theory amplitudes and cross sections at subleading power.

    hep-phnucl-thJHEP(2018)·43 citations
36. 36*

    Fermionic Minimal Dark Matter in 5D Gauge-Higgs Unification

    Nobuhito Maru🇯🇵 · Nobuchika Okada🇺🇸 · Satomi Okada🇯🇵

    We propose a Minimal Dark Matter (MDM) scenario in the context of a simple gauge-Higgs Unification (GHU) model based on the gauge group SU(3) x U(1)' in 5-dimensional Minkowski space with a compactification of the 5th dimension on S^1/Z_2 orbifold. A pair of vector-like SU(3) multiplet fermions in a higher-dimensional representation is introduced in the bulk, and the DM particle is identified with the lightest mass eigenstate among the components in the multiplets. In the original model description, the DM particle communicates with the Standard Model (SM) particles only through the bulk gauge interaction, and hence our model is the GHU version of the MDM scenario. There are two typical realizations of the DM particle in 4-dimensional effective theory: (i) the DM particle is mostly composed of the SM SU(2)_L multiplets, or (ii) the DM is mostly composed of the SM SU(2)_L singlets. Since the case (i) is very similar to the original MDM scenario, we focus on the case (ii), which is a realization of the Higgs-portal DM scenario in the context of the GHU model. We identify an allowed parameter region to be consistent with the current experimental constraints, which will be fully covered by the direct dark matter detection experiments in the near future. In the presence of the bulk multiplet fermions in higher-dimensional $SU(3)$ representations, we reproduce the 125 GeV Higgs boson mass through the renormalization group evolution of Higgs quartic coupling with the compactification scale of 10-100 TeV.

    hep-phPRD(2017)·16 citations
37. 37*

    Relativistic anisotropic hydrodynamics

    Mubarak Alqahtani🇺🇸 · Mohammad Nopoush🇺🇸 · Michael Strickland🇺🇸

    In this paper we review recent progress in relativistic anisotropic hydrodynamics. We begin with a pedagogical introduction to the topic which takes into account the advances in our understanding of this topic since its inception. We consider both conformal and non-conformal systems and demonstrate how one can implement a realistic equation of state using a quasiparticle approach. We then consider the inclusion of non-spheroidal (non-ellipsoidal) corrections to leading-order anisotropic hydrodynamics and present the findings of the resulting second-order viscous anisotropic hydrodynamics framework. We compare the results obtained in both the conformal and non-conformal cases with exact solutions to the Boltzmann equation and demonstrate that, in all known cases, anisotropic hydrodynamics best reproduces the exact solutions. Based on this success, we then discuss the phenomenological application of anisotropic hydrodynamics. Along these lines, we review techniques which can be used to convert a momentum-space anisotropic fluid into hadronic degrees of freedom by generalizing the original idea of Cooper-Frye freeze-out to momentum-space anisotropic systems. And, finally, we present phenomenological results of 3+1d quasiparticle anisotropic hydrodynamic simulations and compare them to experimental data produced in 2.76 TeV Pb-Pb collisions at the LHC. Our results indicate that anisotropic hydrodynamics provides a promising framework for describing the dynamics of the momentum-space anisotropic QGP created in heavy-ion collisions.

    ↳ nucl-thhep-phPPNP(2018)·152 citations
38. 38*

    The Evens and Odds of CMB Anomalies

    A.Gruppuso🇮🇹 · N.Kitazawa🇯🇵 · M.Lattanzi🇮🇹 · N.Mandolesi🇮🇹 · P.Natoli🇮🇹 · A.Sagnotti🇮🇹

    The lack of power of large--angle CMB anisotropies is known to increase its statistical significance at higher Galactic latitudes, where a string--inspired pre--inflationary scale $\Delta$ can also be detected. Considering the Planck 2015 data, and relying largely on a Bayesian approach, we show that the effect is mostly driven by the \emph{even}--$\ell$ harmonic multipoles with $\ell \lesssim 20$, which appear sizably suppressed in a way that is robust with respect to Galactic masking, along with the corresponding detections of $\Delta$. On the other hand, the first \emph{odd}--$\ell$ multipoles are only suppressed at high Galactic latitudes. We investigate this behavior in different sky masks, constraining $\Delta$ through even and odd multipoles, and we elaborate on possible implications. We include low--$\ell$ polarization data which, despite being noise--limited, help in attaining confidence levels of about 3 $\sigma$ in the detection of $\Delta$. We also show by direct forecasts that a future all--sky $E$--mode cosmic--variance--limited polarization survey may push the constraining power for $\Delta$ beyond 5 $\sigma$.

    ↳ astro-ph.COgr-qchep-phhep-thPhys.Dark Univ.(2018)·45 citations
39. 39*

    J1342+0928 Supports the Timeline in the R_h=ct Cosmology

    Fulvio Melia🇺🇸

    The discovery of quasar J1342+0928 (z=7.54) reinforces the time compression problem associated with the premature formation of structure in LCDM. Adopting the Planck parameters, we see this quasar barely 690 Myr after the big bang, no more than several hundred Myr after the transition from Pop III to Pop II star formation. Yet conventional astrophysics would tell us that a 10 solar-mass seed, created by a Pop II/III supernova, should have taken at least 820 Myr to grow via Eddington-limited accretion. This failure by LCDM constitutes one of its most serious challenges, requiring exotic `fixes', such as anomalously high accretion rates, or the creation of enormously massive (~10^5 solar-mass) seeds, neither of which is ever seen in the local Universe, or anywhere else for that matter. Indeed, to emphasize this point, J1342+0928 is seen to be accreting at about the Eddington rate, negating any attempt at explaining its unusually high mass due to such exotic means. In this paper, we aim to demonstrate that the discovery of this quasar instead strongly confirms the cosmological timeline predicted by the R_h=ct universe. We assume conventional Eddington-limited accretion and the time versus redshift relation in this model to calculate when a seed needed to start growing as a function of its mass in order to reach the observed mass of J1342+0928 at z=7.54. Contrary to the tension created in the standard model by the appearance of this massive quasar so early in its history, we find that in the R_h=ct cosmology, a 10 solar-mass seed at z~15 (the start of the Epoch of Reionization at t~878 Myr) would have easily grown into an 8 x 10^8 solar-mass black hole at z=7.54 (t~1.65 Gyr) via conventional Eddington-limited accretion.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phAstron.Astrophys.(2018)·6 citations
40. 40*

    Cyclic Mario Worlds -- Color-Decomposition for One-Loop QCD

    Gregor Kälin🇸🇪

    We present a new color decomposition for QCD amplitudes at one-loop level as a generalization of the Del Duca-Dixon-Maltoni and Johansson-Ochirov decomposition at tree level. Starting from a minimal basis of planar primitive amplitudes we write down a color decomposition that is free of linear dependencies among appearing primitive amplitudes or color factors. The conjectured decomposition applies to any number of quark flavors and is independent of the choice of gauge group and matter representation. The results also hold for higher-dimensional or supersymmetric extensions of QCD. We provide expressions for any number of external quark-antiquark pairs and gluons.

    ↳ hep-thhep-phJHEP(2018)·12 citations
41. 41*

    Observation of ${\Xi }_c(2930{)}^0$ and updated measurement of $B^{-}\to K^{-}{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ at Belle

    Belle Collaboration: Y. B. Li🇨🇳 · C. P. Shen🇨🇳 · I. Adachi🇯🇵 · J. K. Ahn🇰🇷 · H. Aihara🇯🇵 · S. Al Said🇸🇦 · D. M. Asner🇺🇸 · T. Aushev🇷🇺 · R. Ayad🇸🇦 · V. Babu🇮🇳 · I. Badhrees🇸🇦 · A. M. Bakich🇦🇺 and 168 other authors

    We report the first observation of the ${\Xi }_c(2930{)}^0$ charmed-strange baryon with a significance greater than 5$\sigma$. The ${\Xi }_c(2930{)}^0$ is found in its decay to $K^{-}{\Lambda }_c^{+}$ in $B^{-}\to K^{-}{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ decays. The measured mass and width are $[2928.9\pm 3.0(stat.{)}_{-12.0}^{+0.9}(syst.)]$ MeV/$c^2$ and $[19.5\pm 8.4(stat.{)}_{-7.9}^{+5.9}(syst.)]$ MeV, respectively, and the product branching fraction is $\mathcal{B}(B^{-}\to {\Xi }_c(2930{)}^0{\bar{\Lambda }}_c^{-})\mathcal{B}({\Xi }_c(2930{)}^0\to K^{-}{\Lambda }_c^{+})=[1.73\pm 0.45(stat.)\pm 0.21(syst.)]\times 10^{-4}$. We also measure $\mathcal{B}(B^{-}\to K^{-}{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-})=[4.80\pm 0.43(stat.)\pm 0.60(syst.)]\times 10^{-4}$ with improved precision, and search for the charmonium-like state $Y(4660)$ and its spin partner, $Y_{\eta }$, in the ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ invariant mass spectrum. No clear signals of the $Y(4660)$ nor its spin partner are observed and the 90\% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $(772\pm 11)\times 10^{6}B\bar{B}$ pairs collected at the ${\rm Y}(4S)$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.

    ↳ hep-exhep-phEPJC(2018)·67 citations
42. 42*

    Differential equations for loop integrals in Baikov representation

    Jorrit Bosma🇨🇭 · Kasper J. Larsen🇬🇧 · Yang Zhang🇨🇭

    We present a proof that differential equations for Feynman loop integrals can always be derived in Baikov representation without involving dimension-shift identities. We moreover show that in a large class of two- and three-loop diagrams it is possible to avoid squared propagators in the intermediate steps of setting up the differential equations.

    ↳ hep-thhep-phPRD(2018)·49 citations
43. 43*

    Importance and construction of features in identifying new physics signals with deep learning

    Chang-Wei Loh🇨🇳 · Rui Zhang🇨🇳 · Yong-Heng Xu🇨🇳 · Zhi-Qiang Qian🇨🇳 · Si-Cheng Chen🇹🇼 · He-Yang Long🇨🇳 · You-Hang Liu🇨🇳 · De-Wen Cao🇨🇳 · Wei Wang🇨🇳 · Ming Qi🇨🇳

    Advances in machine learning have led to an emergence of new paradigms in the analysis of large data which could assist traditional approaches in the search for new physics amongst the immense Standard Model backgrounds at the Large Hadron Collider. Deep learning is one such paradigm. In this work, we first study feature importance ranking of signal-background classification features with deep learning for two Beyond Standard Model benchmark cases: a multi-Higgs and a supersymmetry scenario. We find that the discovery reach for the multi-Higgs scenario could still increase with additional features. In addition, we also present a deep learning-based approach to construct new features to separate signals from backgrounds using the ATLAS detector as a specific example. We show that the constructed feature is more effective in signal-background separation than commonly used features, and thus is better for physics searches in the detector. As a side application, the constructed feature may be used to identify any momentum bias in a detector. We also utilize a convolutional neural network as part of the momentum bias checking approach.

    ↳ hep-exhep-ph1 citation
44. 44*

    Prospects for detecting eV-scale sterile neutrinos from a galactic supernova

    Tarso Franarin🇬🇧 · Jonathan H. Davis🇬🇧 · Malcolm Fairbairn🇬🇧

    Future neutrino detectors will obtain high-statistics data from a nearby core-collapse supernova. We study the mixing with eV-mass sterile neutrinos in a supernova environment and its effects on the active neutrino fluxes as detected by Hyper-Kamiokande and IceCube. Using a Markov Chain Monte Carlo analysis, we make projections for how accurately these experiments will measure the active-sterile mixing angle ${\theta }_s$ given that there are substantial uncertainties on the expected luminosity and spectrum of active neutrinos from a galactic supernova burst. We find that Hyper-Kamiokande can reconstruct the sterile neutrino mixing and mass in many different situations, provided the neutrino luminosity of the supernova is known precisely. Crucially, we identify a degeneracy between the mixing angle and the overall neutrino luminosity of the supernova. This means that it will only be possible to determine the luminosity if the presence of sterile neutrinos with ${\theta }_s\gtrsim 0.1$ degrees can be ruled out independently. We discuss ways in which this degeneracy may be broken in the future.

    ↳ astro-ph.HEhep-phJCAP(2018)·9 citations
45. 45*

    Fluid dynamics of out of equilibrium boost invariant plasmas

    Jean-Paul Blaizot🇫🇷 · Li Yan🇨🇦

    By solving a simple kinetic equation, in the relaxation time approximation, and for a particular set of moments of the distribution function, we establish a set of equations which, on the one hand, capture exactly the dynamics of the kinetic equation, and, on the other hand, coincide with the hierarchy of equations of viscous hydrodynamics, to arbitrary order in the viscous corrections. This correspondence sheds light on the underlying mechanism responsible for the apparent success of hydrodynamics in regimes that are far from local equilibrium.

    ↳ nucl-thhep-phPLB(2018)·119 citations
46. 46*

    Baryon spectroscopy in the unquenched quark model

    Roelof Bijker🇲🇽 · Gustavo Guerrero-Navarro🇲🇽 · Emmanuel Ortiz-Pacheco🇲🇽

    We discuss some applications of the unquenched quark model which is an extension of the CQM that includes the effects of sea quarks via a 3P0 quark-antiquark pair-creation mechanism. Particular attention is paid to the electromagnetic couplings and beta decays of baryons. It is shown that the observed discrepancies between the experimental data and the predictions of the CQM can be accounted for in large part by the effects of sea quarks in the unquenched quark model.

    ↳ nucl-thhep-phPoS(2018)·1 citation
47. 47*

    Inclusive production of $W$ in pp Collisions in a range of center-of-mass energy from 7 to 100 TeV

    Hasan Ogul🇹🇷 · Emrah Tiras🇺🇸 · Kamuran Dilsiz🇺🇸

    The proton-proton collision energy at Large Hadron Collider (LHC) has been 7, 8 and 13 TeV recently with the goal of reaching to 14 TeV which is the maximum capacity of the LHC. However, there is still more physics yet to be explored and tested beyond the energy regime of the LHC to reach new discoveries. Therefore, a new collider bigger than the LHC machine, which will be able to collide protons at 100 TeV center-of-mass energy, is under consideration by the high-energy physics community. To provide an insight to the transition from LHC to 100 TeV collider, some properties of W processes are investigated in a range of collision energy from 7 to 100 TeV using HERAPDF2.0, MMHT2014, NNPDF3.1 and CT14 NNLO PDF models at NNLO QCD. The considered properties are the production rates of W, the change of uncertainties (PDF, renormalization and factorization scales, strong coupling constant, model and parameterization), and W boson lepton charge asymmetry.

    ↳ hep-exhep-ph0 citations
48. 48*

    $\nu \mathrm{CO}N\mathrm{CEPT}$: Cosmological neutrino simulations from the non-linear Boltzmann hierarchy

    Jeppe Dakin🇩🇰 · Jacob Brandbyge🇩🇰 · Steen Hannestad🇩🇰 · Troels Haugbølle🇩🇰 · Thomas Tram🇩🇰

    In this paper the non-linear effect of massive neutrinos on cosmological structures is studied in a conceptually new way. We have solved the non-linear continuity and Euler equations for the neutrinos on a grid in real space in $N$-body simulations, and closed the Boltzmann hierarchy at the non-linear Euler equation using the stress and pressure perturbations from linear theory. By comparing with state-of-the art cosmological neutrino simulations, we are able to simulate the non-linear neutrino power spectrum very accurately. This translates into a negligible error in the matter power spectrum, and so our $\mathrm{CO}N\mathrm{CEPT}$ code is ideally suited for extracting the neutrino mass from future high precision non-linear observational probes such as Euclid.

    ↳ astro-ph.COhep-phJCAP(2019)·63 citations
49. 49*

    Chiral Anomalous Dispersion

    Andrey Sadofyev🇺🇸 · Srimoyee Sen🇺🇸

    The linearized Einstein equation describing graviton propagation through a chiral medium appears to be helicity dependent. We analyze features of the corresponding spectrum in a collision-less regime above a flat background. In the long wave-length limit, circularly polarized metric perturbations travel with a helicity dependent group velocity that can turn negative giving rise to a new type of an anomalous dispersion. We further show that this chiral anomalous dispersion is a general feature of polarized modes propagating through chiral plasmas extending our result to the electromagnetic sector.

    ↳ hep-thgr-qchep-phJHEP(2018)·4 citations
50. 50*

    On dark matter - dark radiation interaction and cosmic reionization

    Subinoy Das🇮🇳 · Rajesh Mondal🇬🇧 · Vikram Rentala🇮🇳 · Srikanth Suresh🇮🇳

    An intriguing possibility for the dark sector of our universe is that the dark matter particle could interact with a dark radiation component. If the non-gravitational interactions of the dark matter and dark radiation species with Standard Model particles are highly suppressed, then astrophysics and cosmology could be our only windows into probing the dynamics of such a dark sector. It is well known that such dark sectors would lead to suppression of small scale structure, which would be constrained by measurements of the Lyman-$\alpha$ forest. In this work we consider the cosmological signatures of such dark sectors on the reionization history of our universe. Working within the "ETHOS" (effective theory of structure formation) framework, we show that if such a dark sector exists in our universe, the suppression of low mass dark matter halos would also reduce the total number of ionizing photons, thus affecting the reionization history of our universe. We place constraints on the interaction strengths within such dark sectors by using the measured value of the optical depth from the Planck satellite, as well as from demanding a successful reionization history. We compare and contrast such scenarios with warm dark matter scenarios which also suppress structure formation on small scales. In a model where dark matter interacts with a sterile neutrino, we find a bound on the ETHOS parameter $a_4\lesssim 1.2\times 10^6{\text{ Mpc}}^{-1}$. For warm dark matter models, we constrain the mass $m_{\text{WDM}}\gtrsim 0.7\text{ keV}$, which is comparable to bounds obtained from Lyman-$\alpha$ measurements. Future 21-cm experiments will measure the global history of reionization and the neutral hydrogen power spectrum, which could either lead to stronger constraints or discovery of secret dark sector interactions.

    ↳ astro-ph.COhep-phJCAP(2018)·34 citations
51. 51*

    Hyperunified field theory and gravitational gauge-geometry duality

    Yue-Liang Wu🇨🇳

    A hyperunified field theory is built in detail based on the postulates of gauge invariance and coordinate independence along with the conformal scaling symmetry. All elementary particles are merged into a single hyper-spinor field and all basic forces are unified into a fundamental interaction governed by the hyper-spin gauge symmetry SP(1,$D_h$-1). The dimension $D_h$ of hyper-spacetime is conjectured to have a physical origin in correlation with the hyper-spin charge of elementary particles. The hyper-gravifield fiber bundle structure of biframe hyper-spacetime appears naturally with the globally flat Minkowski hyper-spacetime as a base spacetime and the locally flat hyper-gravifield spacetime as a fiber that is viewed as a dynamically emerged hyper-spacetime characterized by a non-commutative geometry. The gravitational origin of gauge symmetry is revealed with the hyper-gravifield that plays an essential role as a Goldstone-like field. The gauge-gravity and gravity-geometry correspondences bring about the gravitational gauge-geometry duality. The basic properties of hyperunified field theory and the issue on the fundamental scale are analyzed within the framework of quantum field theory, which allows us to describe the laws of nature in deriving the gauge gravitational equation with the conserved current and the geometric gravitational equations of Einstein-like type and beyond.

    ↳ hep-thgr-qchep-phEPJC(2018)·26 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.