Mon·Nov 21, 2016Monday·November 21, 2016

1. 01*

   Stashing the stops in multijet events at the LHC

   Sara Diglio🇫🇷 · Lorenzo Feligioni🇫🇷 · Gilbert Moultaka🇫🇷

   While the presence of a light stop is increasingly disfavored by the experimental limits set on R-parity conserving scenarios, the naturalness of supersymmetry could still be safely concealed in the more challenging final states predicted by the existence of non-null R-parity violating couplings. Although R-parity violating signatures are extensively looked for at the Large Hadron Collider, these searches always assume 100\% branching ratios for the direct decays of supersymmetric particles into Standard Model ones. In this paper we scrutinize the implications of relaxing this assumption by focusing on one motivated scenario where the lightest stop is heavier than a chargino and a neutralino. Considering a class of R-parity baryon number violating couplings, we show on general grounds that while the direct decay of the stop into Standard Model particles is dominant for large values of these couplings, smaller values give rise, instead, to the dominance of a plethora of longer decay chains and richer final states that have not yet been analyzed at the LHC, thus weakening the impact of the present experimental stop mass limits. We characterize the case for R-parity baryon number violating couplings in the $10^{-7}-10^{-1}$ range, in two different benchmark points scenarios within the model-independent setting of the low-energy phenomenological Minimal Supersymmetric Standard Model. We identify the different relevant experimental signatures, estimate the corresponding proton--proton cross sections at $\sqrt{s}=14$ TeV and discuss signal versus background issues.

   hep-phhep-exPRD(2017)·9 citations
2. 02*

   Stellar cooling bounds on new light particles: plasma mixing effects

   Edward Hardy🇮🇹 · Robert Lasenby🇨🇦

   Strong constraints on the coupling of new light particles to the Standard Model (SM) arise from their production in the hot cores of stars, and the effects of this on stellar cooling. For new light particles which have an effective in-medium mixing with the photon, plasma effects can result in parametrically different production rates to those obtained from a naive calculation. Taking these previously-neglected contributions into account, we make updated estimates for the stellar cooling bounds on light scalars and vectors with a variety of SM couplings. In particular, we improve the bounds on light (m <~ keV) scalars coupling to electrons or nucleons by up to 3 orders of magnitude in the coupling squared, significantly revise the supernova cooling bounds on dark photon couplings, and qualitatively change the mass dependence of stellar bounds on new vectors. Scalars with mass <~ 2 keV that couple through the Higgs portal are constrained to mixing angle <~ 3*10^-10, which gives the dominant bound for scalar masses above ~ 0.2 eV.

   hep-phJHEP(2017)·392 citations
3. 03*

   Perturbed Yukawa Textures in the Minimal Seesaw Model

   Thomas Rink🇩🇪 · Kai Schmitz🇩🇪

   \noindent We revisit the \textit{minimal seesaw model}, i.e., the type-I seesaw mechanism involving only two right-handed neutrinos. % This model represents an important minimal benchmark scenario for future experimental updates on neutrino oscillations. % It features four real parameters that cannot be fixed by the current data: two $CP$-violating phases, $\delta$ and $\sigma$, as well as one complex parameter, $z$, that is experimentally inaccessible at low energies. % The parameter $z$ controls the structure of the neutrino Yukawa matrix at high energies, which is why it may be regarded as a label or index for all UV completions of the minimal seesaw model. % The fact that $z$ encompasses only two real degrees of freedom allows us to systematically scan the minimal seesaw model over all of its possible UV completions. % In doing so, we address the following question: Suppose $\delta$ and $\sigma$ should be measured at particular values in the future---to what extent is one then still able to realize approximate textures in the neutrino Yukawa matrix? % Our analysis, thus, generalizes previous studies of the minimal seesaw model based on the assumption of exact texture zeros. % In particular, our study allows us to assess the theoretical uncertainty inherent to the common texture ansatz. % One of our main results is that a normal light-neutrino mass hierarchy is, in fact, still consistent with a two-zero Yukawa texture, provided that the two texture zeros receive corrections at the level of $\mathcal{O}\left(\text{10}\%\right)$. % While our numerical results pertain to the minimal seesaw model only, our general procedure appears to be applicable to other neutrino mass models as well.

   hep-phJHEP(2017)·24 citations
4. 04*

   Precision Corrections to Fine Tuning in SUSY

   Matthew R. Buckley🇺🇸 · Angelo Monteux🇺🇸 · David Shih🇺🇸

   Requiring that the contributions of supersymmetric particles to the Higgs mass are not highly tuned places upper limits on the masses of superpartners -- in particular the higgsino, stop, and gluino. We revisit the details of the tuning calculation and introduce a number of improvements, including RGE resummation, two-loop effects, a proper treatment of UV vs. IR masses, and threshold corrections. This improved calculation more accurately connects the tuning measure with the physical masses of the superpartners at LHC-accessible energies. After these refinements, the tuning bound on the stop is now also sensitive to the masses of the 1st and 2nd generation squarks, which limits how far these can be decoupled in Effective SUSY scenarios. We find that, for a fixed level of tuning, our bounds can allow for heavier gluinos and stops than previously considered. Despite this, the natural region of supersymmetry is under pressure from the LHC constraints, with high messenger scales particularly disfavored.

   hep-phJHEP(2017)·21 citations
5. 05*

   A Second Higgs Doublet in the Early Universe: Baryogenesis and Gravitational Waves

   G. C. Dorsch🇩🇪 · S. J. Huber🇬🇧 · T. Konstandin🇩🇪 · J. M. No🇬🇧

   We show that simple Two Higgs Doublet models still provide a viable explanation for the matter-antimatter asymmetry of the Universe via electroweak baryogenesis, even after taking into account the recent order-of-magnitude improvement on the electron-EDM experimental bound by the ACME Collaboration. Moreover we show that, in the region of parameter space where baryogenesis is possible, the gravitational wave spectrum generated at the end of the electroweak phase transition is within the sensitivity reach of the future space-based interferometer LISA.

   hep-phastro-ph.COJCAP(2017)·211 citations
6. 06*

   Reconciling Large And Small-Scale Structure In Twin Higgs Models

   Valentina Prilepina🇺🇸 · Yuhsin Tsai🇺🇸

   We study extensions of the Twin Higgs model that solve the Hierarchy problem and simultaneously address problems of the large- and small-scale structures of the Universe. Besides naturally providing dark matter (DM) candidates as the lightest charged twin fermions, the twin sector contains a light photon and neutrinos, which can modify structure formation relative to the prediction from the $\Lambda$CDM paradigm. We focus on two scenarios. First, we study a Fraternal Twin Higgs model in which the spin-3/2 baryon $\hat{\Omega }\sim (\hat{b}\hat{b}\hat{b})$ and the lepton twin tau $\hat{\tau }$ contribute to the dominant and subcomponent dark matter densities. A non-decoupled scattering between the twin tau and twin neutrino arising from a gauged twin lepton number symmetry provides a drag force that damps the density inhomogeneity of a dark matter subcomponent. Next, we consider the possibility of having the twin hydrogen atom $\hat{H}$ as the dominant DM component. After recombination, a small fraction of the twin protons and leptons remains ionized during structure formation, and their scattering to twin neutrinos through a gauged U$(1{)}_{B-L}$ force provides the mechanism that damps the density inhomogeneity. Both scenarios realize the Partially Acoustic dark matter (PAcDM) scenario and explain the ${\sigma }_8$ discrepancy between the CMB and weak lensing results. Moreover, the self-scattering neutrino behaves as a dark fluid that enhances the size of the Hubble rate $H_0$ to accommodate the local measurement result while satisfying the CMB constraint. For the small-scale structure, the scattering of $\hat{\Omega }$'s and $\hat{H}$'s through the twin photon exchange generates a self-interacting dark matter (SIDM) model that solves the mass deficit problem from dwarf galaxy to galaxy cluster scales.

   hep-phJHEP(2017)·73 citations
7. 07*

   On top quark mass effects to $gg\to ZH$ at NLO

   Alexander Hasselhuhn🇩🇪 · Thomas Luthe🇩🇪 · Matthias Steinhauser🇩🇪

   We compute next-to-leading order QCD corrections to the process $gg\to ZH$. In the effective-theory approach we confirm the results in the literature. We consider top quark mass corrections via an asymptotic expansion and show that there is a good convergence below the top quark threshold which describes approximately {\num a quarter} of the total cross section. Our corrections are implemented in the publicly available {\tt C++} program {\tt ggzh}.

   hep-phJHEP(2017)·44 citations
8. 08*

   Dark matter candidates in the constrained Exceptional Supersymmetric Standard Model

   P. Athron🇦🇺 · A.W. Thomas🇦🇺 · S.J. Underwood🇦🇺 · M.J. White🇦🇺

   The Exceptional Supersymmetric Standard Model (E${}_6$SSM) is a low energy alternative to the MSSM with an extra $U(1)$ gauge symmetry and three generations of matter filling complete 27-plet representations of $E_6$. This provides both new D and F term contributions that raise the Higgs mass at tree level, and a compelling solution to the $\mu$-problem of the MSSM by forbidding such a term with the extra $U(1)$ symmetry. Instead, an effective $\mu$-term is generated from the VEV of an SM singlet which breaks the extra $U(1)$ symmetry at low energies, giving rise to a massive $Z^{\prime }$. We explore the phenomenology of the constrained version of this model (cE${}_6$SSM) in substantially more detail than has been carried out previously, performing a ten dimensional scan that reveals a large volume of viable parameter space. We classify the different mechanisms for generating the measured relic density of dark matter found in the scan, including the identification of a new mechanism involving mixed bino/inert-Higgsino dark matter. We show which mechanisms can evade the latest direct detection limits from the LUX 2016 experiment. Finally we present benchmarks consistent with all the experimental constraints and which could be discovered with the XENON1T experiment.

   hep-phPRD(2017)·19 citations
9. 09*

   Linearly polarized gluons in charmonium and bottomonium production in color octet model

   Asmita Mukherjee🇮🇳 · Sangem Rajesh🇮🇳

   We study the possibility to probe the unpolarized and linearly polarized transverse momentum- dependent gluon distributions in unpolarized pp collision in charmonium and bottomonium produc- tion, employing non-relativistic QCD (NRQCD) based color octet model within transverse momentum dependent (TMD) factorization framework. The transverse momentum (p T ) and rapidity distributions of J/{\psi} and {\Upsilon}(1S) at LHCb, RHIC and AFTER energies are estimated. Significant modulations in transverse momentum spectrum of quarkonium in the low p T region is obtained when contributions of linearly polarized gluons inside an unpolarized proton are taken into account. The results of quarko- nium production in color octet model and color evaporation model are compared.

   hep-phPRD(2017)·39 citations
10. 10*

    An analysis of a minimal vectorlike extension of the Standard Model

    V. Beylin🇷🇺 · M. Bezuglov🇷🇺 · V. Kuksa🇷🇺 · N. Volchanskiy🇷🇺

    We analyze an extension of the Standard Model with an additional SU(2) hypercolor gauge group keeping the Higgs boson as a fundamental field. Vectorlike interactions of new hyperquarks with the intermediate vector bosons are explicitly constructed. We also consider pseudo-Nambu--Goldstone bosons caused by the symmetry breaking SU(4)-> Sp(4). A specific global symmetry of the model with zero hypercharge of the hyperquark doublets ensures the stability of a neutral pseudoscalar field. Some possible manifestations of the lightest states at colliders are also examined.

    hep-phAdv.High Energy Phys.(2017)·17 citations
11. 11*

    QCD-inspired determination of NJL model parameters

    Paul Springer🇩🇪 · Jens Braun🇩🇪 · Stefan Rechenberger🇩🇪 · Fabian Rennecke🇩🇪

    The QCD phase diagram at finite temperature and density has attracted considerable interest over many decades now, not least because of its relevance for a better understanding of heavy-ion collision experiments. Models provide some insight into the QCD phase structure but usually rely on various parameters. Based on renormalization group arguments, we discuss how the parameters of QCD low-energy models can be determined from the fundamental theory of the strong interaction. We particularly focus on a determination of the temperature dependence of these parameters in this work and comment on the effect of a finite quark chemical potential. We present first results and argue that our findings can be used to improve the predictive power of future model calculations.

    hep-phnucl-thEPJ Web Conf.(2017)·24 citations
12. 12*

    Unintegrated Double Parton Distributions - a Summary

    Krzysztof Golec-Biernat🇵🇱 · Anna Stasto🇺🇸

    We present main elements of the construction of unintegrated double parton distribution functions which depend on transverse momenta of partons. We follow the method proposed by Kimber, Martin and Ryskin for a construction of unintegrated single parton distributions from the standard parton distribution functions.

    hep-phAIP Conf.Proc.(2017)·1 citation
13. 13*

    Gluon TMDs in quarkonium production

    Daniël Boer🇳🇱

    Quarkonium production offers good possibilities to study gluon TMDs. In this proceedings contribution this topic is explored for the linearly polarized gluons inside unpolarized hadrons and unpolarized gluons inside transversely polarized hadrons. It is argued that ${\chi }_{b0/2}$ and ${\eta }_b$ production at LHC are best to study the effects of linearly polarized gluons in hadronic collisions, by means of angular independent ratios of ratios of cross sections. This can be directly compared to $\cos 2\varphi$ asymmetries in heavy quark pair and dijet production in DIS at a future high-energy Electron-Ion Collider (EIC), which probe the same TMDs. In the small-$x$ limit this corresponds to the Weizsäcker-Williams (WW) gluon distributions, which should show a change in behavior for transverse momenta around the saturation scale. Together with investigations of the dipole (DP) gluon distributions, this can provide valuable information about the polarization of the Color Glass Condensate if sufficiently small $x$ are reached. Quarkonia can also be useful in the study of single transverse spin asymmetries. For transversely polarized hadrons the gluon distribution can be asymmetric, which is referred to as the Sivers effect. It leads to single spin asymmetries in for instance $J/\psi$ (pair) production at AFTER@LHC, which probe the WW or $f$-type gluon Sivers TMD. It allows for a test of a sign-change relation w.r.t. the gluon Sivers TMD probed at an EIC in open heavy quark pair production. Single spin asymmetries in backward inclusive $C$-odd quarkonium production, such as $J/\psi$ production, may offer probes of the DP or $d$-type gluon Sivers TMD at small $x$-values in the polarized proton, which in that limit corresponds to a correlator of a single Wilson loop, describing the spin-dependent odderon.

    hep-phFew Body Syst.(2017)·39 citations
14. 14*

    QCD-improved limits from neutrinoless double beta decay

    Carolina Arbeláez🇨🇱 · Marcela González🇨🇱 · Sergey Kovalenko🇨🇱 · Martin Hirsch🇪🇸

    We analyze the impact of QCD corrections on limits derived from neutrinoless double beta decay ($0\nu \beta \beta$). As demonstrated previously, the effect of the color-mismatch arising from loops with gluons linking the quarks from different color-singlet currents participating in the effective operators has a dramatic impact on the predictions for some particular Wilson coefficients. Here, we consider all possible contributions from heavy particle exchange, i.e. the so-called short-range mechanism of $0\nu \beta \beta$ decay. All high-scale models (HSM) in this class match at some scale around a $\sim$ few TeV with the corresponding effective theory, containing a certain set of effective dimension-9 operators. Many of these HSM receive contributions from more than one of the basic operators and we calculate limits on these models using the latest experimental data. We also show with one non-trivial example, how to derive limits on more complicated models, in which many different Feynman diagrams contribute to $0\nu \beta \beta$ decay, using our general method.

    hep-phPRD(2017)·23 citations
15. 15*

    An exploratory study of Yang-Mills three-point functions at non-zero temperature

    Markus Q. Huber🇦🇹

    Results for three-point functions of Landau gauge Yang-Mills theory at non-vanishing temperature are presented and compared to lattice results. It is found that the three-gluon vertex is enhanced for temperatures below the phase transition. At very low momenta it becomes negative for all temperatures. Furthermore, truncation effects in functional equations are discussed at the example of three-dimensional Yang-Mills theory for which a self-contained solution is presented.

    hep-phEPJ Web Conf.(2017)·9 citations
16. 16*

    Sensitivity of the T2HKK experiment to the non-standard interaction

    Shinya Fukasawa🇯🇵 · Monojit Ghosh🇯🇵 · Osamu Yasuda🇯🇵

    If the flavor dependent non-standard interactions (NSI) in neutrino propagation exist, then the matter effect is modified and the modification is parametrized by the dimensionless parameter ${ϵ}_{\alpha \beta }(\alpha ,\beta =e,\mu ,\tau )$. In this paper we discuss the sensitivity of the T2HKK experiment, whose possibility is now seriously discussed as a future extension of the T2K experiment, to such NSI. On the assumption that ${ϵ}_{\alpha \mu }=0(\alpha =e,\mu \tau )$ and ${ϵ}_{\tau \tau }=|{ϵ}_{e\tau }|/(1+{ϵ}_{ee})$, which are satisfied by other experiments to a good approximation, we find that, among the possible off-axis flux configurations of $1.3^{\circ }$, $1.5^{\circ }$, $2.0^{\circ }$ and $2.5^{\circ }$, the case of the off-axis angle $1.3^{\circ }$ gives the highest sensitivity to ${ϵ}_{ee}$ and $|{ϵ}_{e\tau }|$. Our results show that the $1.3^{\circ }$ off-axis configuration can exclude NSI for $|{ϵ}_{ee}|\gtrsim 1$ or $|{ϵ}_{e\tau }|\gtrsim 0.2$ at 3$\sigma$. We also find that in the presence of NSI, T2HKK (for the off-axis angle $1.3^{\circ }$) has better sensitivity to the two CP phases (${\delta }_{CP}$ and arg(${ϵ}_{e\tau }$)) than DUNE. This is because of the synergy between the two detectors i.e., one at Kamioka and one at Korea. T2HKK has better sensitivity to the CP phases than the atmospheric neutrino experiment at Hyperkamiokande in inverted hierarchy, but in normal hierarchy the atmospheric neutrino experiment has the best sensitivity to the CP phases.

    hep-phPRD(2017)·57 citations
17. 17*

    The growth with energy of exclusive $J/\Psi$ and ${\rm Y}$ photo-production cross-sections and BFKL evolution

    Martin Hentschinski🇲🇽

    We investigate whether NLO BFKL evolution is capable to describe the energy dependence of the exclusive photo-production cross-section of vector mesons $J/\Psi$ and ${\rm Y}$ on protons. Our description is based on available NLO BFKL fits of the proton impact factor in inclusive DIS, which allow us to construct the necessary scattering amplitude at zero momentum transfer $t=0$. Assuming an exponential drop-off with $t$, this result allows us to calculate the exclusive photoproduction cross-section. Comparing our results with both HERA data (measured by H1 and ZEUS collaborations in $ep$ collision) and LHC data (measured by ALICE, CMS and LHCb collaborations in ultra-peripheral $pp$ and $pPb$ collision) we find that our framework provides a very good description of the energy dependence of the $J/\Psi$ and ${\rm Y}$ photoproduction cross-section, providing therefore further evidence for BFKL evolution at the LHC. The available fits of the proton impact factor require on the other hand an adjustment in the overall normalization.

    hep-phAIP Conf.Proc.(2017)·0 citations
18. 18*

    Dark Matter Phenomenology of SM and Enlarged Higgs Sectors Extended with Vector Like Leptons

    Andrei Angelescu🇫🇷 · Giorgio Arcadi🇩🇪

    We will investigate the scenario in which the Standard Model (SM) Higgs sector and its 2-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the "portal" for the interactions between the Standard Model and a fermionic Dark Matter (DM) candidate. The latter is the lightest stable neutral particle of a family of vector-like leptons (VLLs). We will provide an extensive overview of this scenario combining the constraints purely coming from DM phenomenology with more general constraints like Electro-weak Precision Tests (EWPT) as well as with collider searches. In the case that the new fermionic sector interacts with the SM Higgs sector, constraints from DM phenomenology force the new states to lie above the TeV scale. This requirement is relaxed in the case of 2HDM. Nevertheless, strong constraints coming from Electroweak Precision Tests (EWPT) and the Renormalization Group Equations (RGEs) limit the impact of VLFs on collider phenomenology.

    hep-phEPJC(2017)·21 citations
19. 19*

    Charmed Meson Scattering from Lattice QCD

    Graham Moir🇬🇧

    State-of-the-art lattice QCD calculations of scattering amplitudes in coupled-channel $D\pi$, $D\eta$ and $D_s\bar{K}$ scattering, as well elastic $DK$ scattering are discussed. The methodology employed allows a determination of the relevant poles in the scattering matrix, while also providing a measure of the coupling of each channel to a given pole. By investigating $S$, $P$ and $D$ wave interactions, the nature of states with $J^P=0^{+}$, relevant for the $D_0^{\ast }(2400)$ and $D_{s0}^{\ast }(2317)$, as well as states with $J^P=1^{-},2^{+}$ are discussed.

    ↳ hep-lathep-phPoS(2016)·1 citation
20. 20*

    Dielectric Haloscopes: A New Way to Detect Axion Dark Matter

    The MADMAX Working Group: Allen Caldwell🇩🇪 · Gia Dvali🇩🇪 · Bela Majorovits🇩🇪 · Alexander Millar🇩🇪 · Georg Raffelt🇩🇪 · Javier Redondo🇪🇸 · Olaf Reimann🇩🇪 · Frank Simon🇩🇪 · Frank Steffen🇩🇪

    We propose a new strategy to search for dark matter axions in the mass range of 40--400 $\mu$eV by introducing dielectric haloscopes, which consist of dielectric disks placed in a magnetic field. The changing dielectric media cause discontinuities in the axion-induced electric field, leading to the generation of propagating electromagnetic waves to satisfy the continuity requirements at the interfaces. Large-area disks with adjustable distances boost the microwave signal (10--100 GHz) to an observable level and allow one to scan over a broad axion mass range. A sensitivity to QCD axion models is conceivable with 80 disks of 1 m${}^2$ area contained in a $10$ Tesla field.

    ↳ physics.ins-detastro-ph.COastro-ph.HEhep-ex+1PRL(2017)·485 citations
21. 21*

    Excluded-volume effects for a hadron gas in Yang-Mills theory

    Paolo Alba🇩🇪 · Wanda Maria Alberico🇮🇹 · Alessandro Nada🇮🇹 · Marco Panero🇮🇹 · Horst Stöcker🇩🇪

    When the multiplicities of particles produced in heavy-ion collisions are fitted to the hadron-resonance-gas model, excluded-volume effects play a significant role. In this work, we study the impact of such effects on the equation of state of pure Yang-Mills theory at low temperatures, comparing the predictions of the statistical model with lattice results. In particular, we present a detailed analysis of the SU(2) and SU(3) Yang-Mills theories: we find that, for both of them, the best fits to the equilibrium thermodynamic quantities are obtained when one assumes that the volume of different glueball states is inversely proportional to their mass. The implications of these findings for QCD are discussed.

    ↳ hep-lathep-phnucl-thPRD(2017)·26 citations
22. 22*

    Quantum gravity and Standard-Model-like fermions

    Astrid Eichhorn🇩🇪 · Stefan Lippoldt🇩🇪

    We discover that chiral symmetry does not act as an infrared attractor of the renormalization group flow under the impact of quantum gravity fluctuations. Thus, observationally viable quantum gravity models must respect chiral symmetry. In our truncation, asymptotically safe gravity does, as a chiral fixed point exists. A second non-chiral fixed point with massive fermions provides a template for models with dark matter. This fixed point disappears for more than 10 fermions, suggesting that an asymptotically safe ultraviolet completion for the standard model plus gravity enforces chiral symmetry.

    ↳ gr-qchep-phhep-thPLB(2017)·113 citations
23. 23*

    Constraints on dark matter scenarios from measurements of the galaxy luminosity function at high redshifts

    P.S. Corasaniti🇫🇷 · S. Agarwal🇫🇷 · D.J.E. Marsh🇬🇧 · S. Das🇮🇳

    We use state-of-art measurements of the galaxy luminosity function (LF) at z=6, 7 and 8 to derive constraints on warm dark matter (WDM), late-forming dark matter (LFDM) and ultra-light axion dark matter (ULADM) models alternative to the cold dark matter (CDM) paradigm. To this purpose we have run a suite of high-resolution N-body simulations to accurately characterise the low mass-end of the halo mass function and derive DM model predictions of the high-z luminosity function. In order to convert halo masses into UV-magnitudes we introduce an empirical approach based on halo abundance matching which allows us to model the LF in terms of the amplitude and scatter of the ensemble average star formation rate halo mass relation of each DM model, $⟨\mathrm{SFR}({\mathrm{M}}_{\mathrm{h}},z)⟩$. We find that independent of the DM scenario the average SFR at fixed halo mass increases from z=6 to 8, while the scatter remains constant. At halo mass ${\mathrm{M}}_{\mathrm{h}}\gtrsim 10^{12}{\mathrm{M}}_{\odot }$ h${}^{-1}$ the average SFR as function of halo mass follows a double power law trend that is common to all models, while differences occur at smaller masses. In particular, we find that models with a suppressed low-mass halo abundance exhibit higher SFR compared to the CDM results. Using deviance statistics we obtain a lower limit on the WDM thermal relic particle mass, $m_{\mathrm{WDM}}\gtrsim 1.5$ keV at $2\sigma$. In the case of LFDM models, the phase transition redshift parameter is bounded to $z_t\gtrsim 8\cdot 10^5$ at $2\sigma$. We find ULADM best-fit models with axion mass $m_a\gtrsim 1.6\cdot 10^{-22}$ eV to be well within $2\sigma$ of the deviance statistics. We remark that measurements at $z=6$ slightly favour a flattening of the LF at faint UV-magnitudes. This tends to prefer some of the non-CDM models in our simulation suite, although not at a statistically significant level to distinguish them from CDM.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2017)·146 citations
24. 24*

    511 keV Line Emission from Nearby Spherical Dwarf Galaxies

    Kyle Lawson🇨🇦 · Ariel Zhitnitsky🇨🇦

    The observed galactic 511 keV line has been interpreted in a number of papers as a possible signal of dark matter annihilation within the galactic bulge. If this is the case then we should expect a similar spectral feature associated with nearby dwarf galaxies which are dark matter dominated. It has recently been argued [1] that the absence of such a signal excludes a dark matter explanation as the major source for the galactic 511 keV line. In the model presented here dark matter in the form of heavy quark nuggets produces the galactic 511 keV emission line through interactions with the visible matter. It is argued, however, that this type of interaction is not subject to the strong dark matter annihilation constraints presented in [1].

    ↳ astro-ph.COhep-phJCAP(2017)·10 citations
25. 25*

    Soft Gravitons and the Flat Space Limit of Anti-deSitter Space

    Tom Banks🇺🇸 · Willy Fischler🇺🇸

    We argue that flat space amplitudes for the process $2\to n$ gravitons at center of mass energies $\sqrt{s}$ much less than the Planck scale, will coincide approximately with amplitudes calculated from correlators of a boundary CFT for AdS space of radius $R\gg L_P$, only when $n<R/L_P$ . For larger values of $n$ in AdS space, insisting that all the incoming energy enters "the arena" [arXiv:hep-th/9901079], implies the production of black holes, whereas there is no black hole production in the flat space amplitudes. We also argue, from unitarity, that flat space amplitudes for all $n$ are necessary to reconstruct the complicated singularity at zero momentum in the $2\to 2$ amplitude, which can therefore not be reproduced as the limit of an AdS calculation. Applying similar reasoning to amplitudes for real black hole production in flat space, we argue that unitarity of the flat space S-matrix cannot be assessed or inferred from properties of CFT correlators.

    ↳ hep-thgr-qchep-ph11 citations
26. 26*

    Holographic QCD for H-dibaryon (uuddss)

    Hideo Suganuma🇯🇵 · Kohei Matsumoto (Kyoto U.)🇯🇵

    The H-dibaryon (uuddss) is studied in holographic QCD for the first time. In holographic QCD, four-dimensional QCD, i.e., SU($N_c$) gauge theory with chiral quarks, can be formulated with $S^1$-compactified D4/D8/$\overline{D8}$-brane system. In holographic QCD with large $N_c$, all the baryons appear as topological chiral solitons of Nambu-Goldstone bosons and (axial) vector mesons, and the H-dibaryon can be described as an SO(3)-type topological soliton with $B=2$. We derive the low-energy effective theory to describe the H-dibaryon in holographic QCD. The H-dibaryon mass is found to be twice of the $B=1$ hedgehog-baryon mass, $M_{\mathrm{H}}\simeq 2.00M_{B=1}^{\mathrm{HH}}$, and is estimated about 1.7GeV, which is smaller than mass of two nucleons (flavor-octet baryons), in the chiral limit.

    ↳ hep-thhep-phEPJ Web Conf.(2017)·7 citations
27. 27*

    Two Photon Transition Form Factor of $\bar{c}c$ Quarkonia

    Jing Chen🇨🇳 · Minghui Ding🇨🇳 · Lei Chang🇨🇳 · Yu-xin Liu🇨🇳

    The two photon transition of $\bar{c}c$ quarkonia are studied within a covariant approach based on the consistent truncation scheme of the quantum chromodynamics Dyson-Schwinger equation for the quark propagator and the Bethe--Salpeter equation for the mesons. We find the decay widths of ${\eta }_c^{}\to \gamma \gamma$ and ${\chi }_{c0,2}^{}\to \gamma \gamma$ in good agreement with experimental data. The obtained transition form factor of ${\eta }_c^{}\to \gamma {\gamma }^{\ast }$ for a wide range of space-like photon momentum transfer squared is also in agreement with the experimental findings of the BABAR experiment. As a by-product, the decay widths of ${\eta }_b^{},{\chi }_{b0,2}^{}\to \gamma \gamma$ and the transition form factor of ${\eta }_b^{},{\chi }_{c0,b0}^{}\to \gamma {\gamma }^{\ast }$ are predicted, which await for experimental test.

    ↳ nucl-thhep-phPRD(2017)·43 citations
28. 28*

    Nucleon resonance structure in the finite volume of lattice QCD

    Jia-Jun Wu🇦🇺 · H. Kamano🇯🇵 · T.-S. H. Lee🇺🇸 · D. B. Leinweber🇦🇺 · A.W. Thomas🇦🇺

    An approach for relating the nucleon resonances extracted from $\pi N$ reaction data to lattice QCD calculations has been developed by using the finite-volume Hamiltonian method. Within models of $\pi N$ reactions, bare states are introduced to parametrize the intrinsic excitations of the nucleon. We show that the resonance pole positions can be related to the probability $P_{N^{\ast }}(E)$ of finding the bare state, $N^{\ast }$, in the $\pi N$ scattering states in infinite volume. We further demonstrate that the probability $P_{N^{\ast }}^V(E)$ of finding the same bare states in the eigenfunctions of the underlying Hamiltonian in finite volume approaches $P_{N^{\ast }}(E)$ as the volume increases. Our findings suggest that the comparison of $P_{N^{\ast }}(E)$ and $P_{N^{\ast }}^V(E)$ can be used to examine whether the nucleon resonances extracted from the $\pi N$ reaction data within the dynamical models are consistent with lattice QCD calculation. We also discuss the measurement of $P_{N^{\ast }}^V(E)$ directly from lattice QCD. The practical differences between our approach and the approach using the Lüscher formalism to relate LQCD calculations to the nucleon resonance poles embedded in the data are also discussed.

    ↳ hep-lathep-phnucl-exnucl-thPRD(2017)·23 citations
29. 29*

    Chiral transport of neutrinos in supernovae

    Naoki Yamamoto🇯🇵

    The conventional neutrino transport theory for core-collapse supernovae misses one key property of neutrinos: the left-handedness. The chirality of neutrinos modifies the hydrodynamic behavior at the macroscopic scale and leads to topological transport phenomena. We argue that such transport phenomena should play important roles in the evolution of core-collapse supernovae, and, in particular, lead to a tendency toward the inverse energy cascade from small to larger scales, which may be relevant to the origin of the supernova explosion.

    ↳ astro-ph.HEhep-phnucl-thEPJ Web Conf.(2017)·5 citations
30. 30*

    Controlling quark mass determinations non-perturbatively in three-flavour QCD

    Isabel Campos🇪🇸 · Patrick Fritzsch🇪🇸 · Carlos Pena🇪🇸 · David Preti🇪🇸 · Alberto Ramos🇨🇭 · Anastassios Vladikas🇮🇹

    The determination of quark masses from lattice QCD simulations requires a non-perturbative renormalization procedure and subsequent scale evolution to high energies, where a conversion to the commonly used MS-bar scheme can be safely established. We present our results for the non-perturbative running of renormalized quark masses in Nf=3 QCD between the electroweak and a hadronic energy scale, where lattice simulations are at our disposal. Recent theoretical advances in combination with well-established techniques allows to follow the scale evolution to very high statistical accuracy, and full control of systematic effects.

    ↳ hep-lathep-phEPJ Web Conf.(2017)·4 citations
31. 31*

    Models for Small-Scale Structure on Cosmic Strings: II. Scaling and its stability

    J. P. P. Vieira🇵🇹 · C.J.A.P. Martins🇵🇹 · E.P.S. Shellard🇬🇧

    We make use of the formalism described in a previous paper [Martins {\it et al.} Phys. Rev. D90 (2014) 043518] to address general features of wiggly cosmic string evolution. In particular, we highlight the important role played by poorly understood energy loss mechanisms and propose a simple ansatz which tackles this problem in the context of an extended velocity-dependent one-scale model. We find a general procedure to determine all the scaling solutions admitted by a specific string model and study their stability, enabling a detailed comparison with future numerical simulations. A simpler comparison with previous Goto-Nambu simulations supports earlier evidence that scaling is easier to achieve in the matter era than in the radiation era. In addition, we also find that the requirement that a scaling regime be stable seems to notably constrain the allowed range of energy loss parameters.

    ↳ astro-ph.COastro-ph.HEgr-qchep-phPRD(2016)·16 citations
32. 32*

    Physics Potentials with the Second Hyper-Kamiokande Detector in Korea

    Hyper-Kamiokande proto-collaboration: K. Abe🇯🇵 · Ke. Abe🇯🇵 · S.H. Ahn🇰🇷 · H. Aihara🇯🇵 · A. Aimi🇮🇹 · R. Akutsu🇯🇵 · C. Andreopoulos🇬🇧 · I. Anghel🇺🇸 · L.H.V. Anthony🇬🇧 · M. Antonova🇷🇺 · Y. Ashida🇯🇵 · V. Aushev🇺🇦 and 342 other authors

    Hyper-Kamiokande consists of two identical water-Cherenkov detectors of total 520~kt with the first one in Japan at 295~km from the J-PARC neutrino beam with 2.5${}^{\text{o}}$ Off-Axis Angles (OAAs), and the second one possibly in Korea in a later stage. Having the second detector in Korea would benefit almost all areas of neutrino oscillation physics mainly due to longer baselines. There are several candidate sites in Korea with baselines of 1,000$\sim$1,300~km and OAAs of 1${}^{\text{o}}$$\sim$3${}^{\text{o}}$. We conducted sensitivity studies on neutrino oscillation physics for a second detector, either in Japan (JD $\times$ 2) or Korea (JD + KD) and compared the results with a single detector in Japan. Leptonic CP violation sensitivity is improved especially when the CP is non-maximally violated. The larger matter effect at Korean candidate sites significantly enhances sensitivities to non-standard interactions of neutrinos and mass ordering determination. Current studies indicate the best sensitivity is obtained at Mt. Bisul (1,088~km baseline, $1.3^{\circ }$ OAA). Thanks to a larger (1,000~m) overburden than the first detector site, clear improvements to sensitivities for solar and supernova relic neutrino searches are expected.

    ↳ hep-exhep-phphysics.ins-detPTEP(2018)·327 citations
33. 33*

    Inflationary primordial black holes for the LIGO gravitational wave events and pulsar timing array experiments

    Keisuke Inomata🇯🇵 · Masahiro Kawasaki🇯🇵 · Kyohei Mukaida🇯🇵 · Yuichiro Tada🇯🇵 · Tsutomu T. Yanagida🇯🇵

    Primordial black holes (PBHs) are one of the candidates to explain the gravitational wave (GW) signals observed by the LIGO detectors. Among several phenomena in the early Universe, cosmic inflation is a major example to generate PBHs from large primordial density perturbations. In this paper, we discuss the possibility to interpret the observed GW events as mergers of PBHs which are produced by cosmic inflation. The primordial curvature perturbation should be large enough to produce a sizable amount of PBHs and thus we have several other probes to test this scenario. We point out that the current pulsar timing array (PTA) experiments already put severe constraints on GWs generated via the second-order effects, and that the observation of the cosmic microwave background (CMB) puts severe restriction on its $\mu$ distortion. In particular, it is found that the scalar power spectrum should have a very sharp peak at $k\sim 10^6$ Mpc${}^{-1}$ to fulfill the required abundance of PBHs while evading constraints from the PTA experiments together with the $\mu$ distortion. We propose a mechanism which can realize such a sharp peak. In the future, simple inflation models that generate PBHs via almost Gaussian fluctuations could be probed/excluded.

    ↳ astro-ph.COhep-phPRD(2017)·278 citations
34. 34*

    Two-photon exchange correction to $2S$-$2P$ splitting in muonic helium-3 ions

    Carl E. Carlson🇺🇸 · Mikhail Gorchtein🇩🇪 · Marc Vanderhaeghen🇩🇪

    We calculate the two-photon exchange correction to the Lamb shift in muonic helium-3 ions within the dispersion relations framework. Part of the effort entailed making analytic fits to the electron-${}^3$He quasielastic scattering data set, for purposes of doing the dispersion integrals. Our result is that the energy of the 2$S$ state is shifted downwards by two-photon exchange effects by 15.14(49) meV, in good accord with the result obtained from a potential model and effective field theory calculation.

    ↳ nucl-thhep-phnucl-exPRA(2017)·38 citations
35. 35*

    Validity of Chemical Equilibrium Approach in the Study of Kinetic Freeze-out in p-Pb Collisions at LHC

    Inam-ul Bashir🇮🇳 · Hamid Nanda🇮🇳 · Saeed Uddin🇮🇳

    Transverse momentum spectra of identified pions, Kaons , protons and Lambdas produced at mid-rapidity (0 < ycm < 0.5) in p-Pb collisions at root(sNN) = 5.02 TeV is studied for different collision centralities by using a Unified Statistical Thermal Freeze-out Model (USTFM). A fairly good agreement is seen between the calculated results and the experimental data points taken from the ALICE experiment. Kinetic freeze-out conditions are extracted from the fits of the transverse momentum spectra of these hadrons for each centrality class. A comparison of the obtained freeze-out parameters with those of heavy-ion collisions (Pb + Pb) is made and discussed.

    ↳ nucl-thhep-ph0 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.