Wed·Aug 16, 2017Wednesday·August 16, 2017

1. 01*

   Oscillating Spin-2 Dark Matter

   Luca Marzola🇪🇪 · Martti Raidal🇪🇪 · Federico R. Urban🇪🇪

   We show that the coherent oscillations of a spin-2 field from bimetric theory can easily account for the observed dark matter abundance. We obtain the equation of motion for the field in a cosmological setting and discuss in detail the phenomenology of the model. The framework is testable in precision measurements of oscillating electric charge in atomic clocks, using atomic spectroscopy and in dedicated resonant mass detectors as well as in axion-like-particles experiments, which therefore provide a new window to probe and test gravity itself. We also comment on possible multimetric extensions of the framework that straightforwardly implement the clockwork mechanism for gravity.

   hep-phastro-ph.COhep-thPRD(2018)·100 citations
2. 02*

   The Role of QCD Monopoles in Jet Quenching

   Adith Ramamurti🇺🇸 · Edward Shuryak🇺🇸

   QCD monopoles are magnetically charged quasiparticles whose Bose-Einstein condensation (BEC) at $T<T_c$ creates electric confinement and flux tubes. The "magnetic scenario" of QCD proposes that scattering on the non-condensed component of the monopole ensemble at $T>T_c$ is responsible for the unusual kinetic properties of QGP. In this paper, we study the contribution of the monopoles to jet quenching phenomenon, using the BDMPS framework and hydrodynamic backgrounds. In the lowest order for cross sections, we calculate the nuclear modification factor, $R_{\text{AA}},$ and azimuthal anisotropy, $v_2$, of jets, as well as the dijet asymmetry, $A_j$, and compare those to the available data. We find relatively good agreement with experiment when using realistic hydrodynamic backgrounds. In addition, we find that event-by-event fluctuations are not necessary to reproduce $R_{\text{AA}}$ and $v_2$ data, but play a role in $A_j$. Since the monopole-induced effects are maximal at $T\approx T_c$, we predict that their role should be significantly larger, relative to quarks and gluons, at lower RHIC energies.

   hep-phnucl-thPRD(2018)·14 citations
3. 03*

   COHERENT constraints on nonstandard neutrino interactions

   Jiajun Liao🇺🇸 · Danny Marfatia🇺🇸

   Coherent elastic neutrino-nucleus scattering consistent with the standard model has been observed by the COHERENT experiment. We study nonstandard neutrino interactions using the detected spectrum. For the case in which the nonstandard interactions (NSI) are induced by a vector mediator lighter than 50 MeV, we obtain constraints on the coupling of the mediator. For a heavier mediator, we find that degeneracies between the NSI parameters severely weaken the constraints. However, these degeneracies do not affect COHERENT constraints on the effective NSI parameters for matter propagation in the Earth.

   hep-phhep-exnucl-exPLB(2017)·186 citations
4. 04*

   Reactor and Atmospheric Neutrino Mixing Angles' Correlation as a Probe for New Physics

   Pedro Pasquini🇧🇷

   We performed a simulation on the DUNE experiment to probe the capability of future neutrino long-baseline experiments' ability to constrain the parameter space of high-energy models by using the correlation between the atmospheric and reactor mixing angles. As an example, we took the Tetrahedral Flavour Symmetry model, which predicts a strong relation between the non-zero value of ${\theta }_{13}$ and deviation of ${\theta }_{23}$ from the maximality. We show that in this case, the model can realistically be excluded in more than $3\sigma$ for most of the parameter space. We also study the octant degeneracy at DUNE and its impact on the sensitivity of such models.

   hep-phPRD(2017)·4 citations
5. 05*

   Renormalization Group Flow of the Higgs Potential

   Holger Gies🇩🇪 · René Sondenheimer🇩🇪

   We summarize results for local and global properties of the effective potential for the Higgs boson obtained from the functional renormalization group, which allows to describe the effective potential as a function of both scalar field amplitude and RG scale. This sheds light onto the limitations of standard estimates which rely on the identification of the two scales and helps clarifying the origin of a possible property of meta-stability of the Higgs potential. We demonstrate that the inclusion of higher-dimensional operators induced by an underlying theory at a high scale (GUT or Planck scale) can relax the conventional lower bound on the Higgs mass derived from the criterion of absolute stability.

   hep-phhep-thPhil.Trans.Roy.Soc.Lond.A(2018)·20 citations
6. 06*

   Strong and radiative decays of the doubly charmed baryons

   Li-Ye Xiao🇨🇳 · Kai-Lei Wang🇨🇳 · Qi-Fang Lü🇨🇳 · Xian-Hui Zhong🇨🇳 · Shi-Lin Zhu🇨🇳

   We have systematically studied the strong and radiative decays of the low-lying $1P$-wave doubly charmed baryons. Some interesting observations are: (i) The states ${\Xi }_{cc}^{\ast }$ and ${\Omega }_{cc}^{\ast }$ with $J^P=3/2^{+}$ have a fairly large decay rate into the ${\Xi }_{cc}\gamma$ and ${\Omega }_{cc}\gamma$ channels with a width $\sim 15$ and $\sim 7$ keV, respectively. (ii) The lowest lying excited doubly charmed baryons are dominated by the $1P$ $\rho$ mode excitations, which should be quite narrow states. They decay into the ground state with $J^P=1/2^{+}$ through the radiative transitions with a significant ratio. (iii) The total decay widths of the first orbital excitations of $\lambda$ mode ($1P_{\lambda }$ states with $J^P=1/2^{-}$, $3/2^{-}$, $5/2^{-}$) are about $\Gamma \sim 100$ MeV, and the ratio between the radiative and hadronic decay widths is about $\mathcal{O}(10^{-3})$.

   hep-phPRD(2017)·96 citations
7. 07*

   CP violating anomalous couplings in $W$ jet production at the LHC

   Hai Tao Li🇦🇺 · German Valencia🇦🇺

   T-odd correlations in $Wj$ production at the LHC have been studied recently as a way to measure a phase produced by QCD at NLO by Frederix et. al. That study found that the induced asymmetry could be observed with 20 fb${}^{-1}$ of 8 TeV data. These T-odd asymmetries can also be induced by CP violating new physics interfering with the SM at LO. In this paper we study this possibility using effective Lagrangians to describe the new physics. We find that the leading contribution arises at dimension eight, and that it necessarily introduces flavor changing neutral currents as well. We discuss the constraints that can be placed on the flavor structure of the new physics operator from studies of FCNC in kaon and B meson decays and then compare the T-odd correlations in $Wj$ induced by CP violating new physics to those induced by QCD at NLO. We quantify the level at which these couplings can be probed at the LHC, and find that they will not affect a measurement of the NLO QCD phases.

   hep-phPRD(2017)·9 citations
8. 08*

   The Impact of Two-Loop Effects on the Scenario of MSSM Higgs Alignment without Decoupling

   Howard E. Haber🇺🇸 · Sven Heinemeyer🇪🇸 · Tim Stefaniak🇺🇸

   In multi-Higgs models, the properties of one neutral scalar state approximate those of the Standard Model (SM) Higgs boson in a limit where the corresponding scalar field is roughly aligned in field space with the scalar doublet vacuum expectation value. In a scenario of alignment without decoupling, a SM-like Higgs boson can be accompanied by additional scalar states whose masses are of a similar order of magnitude. In the Minimal Supersymmetric Standard Model (MSSM), alignment without decoupling can be achieved due to an accidental cancellation of tree-level and radiative loop-level effects. In this paper we assess the impact of the leading two-loop O(alpha_s h_t^2) corrections on the Higgs alignment condition in the MSSM. These corrections are sizable and important in the relevant regions of parameter space and furthermore give rise to solutions of the alignment condition that are not present in the approximate one-loop description. We provide a comprehensive numerical comparison of the alignment condition obtained in the approximate one-loop and two-loop approximations, and discuss its implications for phenomenologically viable regions of the MSSM parameter space.

   hep-phEPJC(2017)·28 citations
9. 09*

   Mass spectra and radiative transitions of doubly heavy baryons in a relativized quark model

   Qi-Fang Lü🇨🇳 · Kai-Lei Wang🇨🇳 · Li-Ye Xiao🇨🇳 · Xian-Hui Zhong🇨🇳

   We study the mass spectra and radiative decays of doubly heavy baryons within the diquark picture in a relativized quark model. The mass of the $J^P=1/2^{+}$ ${\Xi }_{cc}$ ground state is predicted to be 3606 MeV, which is consistent with the mass of ${\Xi }_{cc}^{++}(3621)$ newly observed by the LHCb collaboration. The predicted mass gap between two $S$ wave states, ${\Xi }_{cc}^{\ast }$ ($J^P=3/2^{+}$) and ${\Xi }_{cc}$ ($J^P=1/2^{+}$), is 69 MeV. Furthermore, the radiative transitions of doubly heavy baryons are also estimated by using the realistic wave functions obtained from relativized quark model. The radiative decay widths of ${\Xi }_{cc}^{\ast ++}\to {\Xi }_{cc}^{++}\gamma$ and ${\Xi }_{cc}^{\ast +}\to {\Xi }_{cc}^{+}\gamma$ are predicted to be about 7 and 4 keV, respectively. These predictions of doubly heavy baryons can provide helpful information for future experimental searches.

   hep-phhep-exnucl-thPRD(2017)·121 citations
10. 10*

    Direct determination of Wilson coefficients using $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$ decays

    T. Hurth🇩🇪 · C. Langenbruch🇩🇪 · F. Mahmoudi🇫🇷

    A method to directly determine the Wilson coefficients for rare $b\to s$ transitions using $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$ decays in an unbinned maximum likelihood fit is presented. The method has several advantages compared to the conventional determination of the Wilson coefficients from angular observables that are determined in bins of $q^2$, the square of the mass of the dimuon system. The method uses all experimental information in an optimal way and automatically accounts for experimental correlations. Performing pseudoexperiments, we show the improved sensitivity of the proposed method for the Wilson coefficients. We also demonstrate that it will be possible to use the method with the combined Run 1 and 2 data sample taken by the LHCb experiment.

    hep-phhep-exJHEP(2017)·27 citations
11. 11*

    Non-global and rapidity logarithms in narrow jet broadening

    Thomas Becher🇨🇭 · Rudi Rahn🇨🇭 · Ding Yu Shao🇨🇭

    We derive an all-order factorization theorem for the narrow jet broadening event shape, a measure of the transverse momentum in jet events. This is a non-global observable which receives logarithmically enhanced contributions associated with the large rapidity difference between soft and collinear radiation and which is also sensitive to soft recoil effects. Our work is the first factorization analysis of an observable of this type and we show that with regard to the non-global nature, the rapidity logarithms do not constitute an essential complication since they can be tied to the jet function, which is the same as for global observables. As a consequence, the leading non-global logarithms in narrow jet broadening are encoded in the same overall factor relevant for the hemisphere soft function and light jet mass.

    hep-phJHEP(2017)·26 citations
12. 12*

    NLO Effects for Doubly Heavy Baryon in QCD Sum Rules

    Chen-Yu Wang🇨🇳 · Ce Meng🇨🇳 · Yan-Qing Ma🇨🇳 · Kuang-Ta Chao🇨🇳

    With the QCD sum rules approach, we study the newly discovered doubly heavy baryon ${\Xi }_{cc}^{++}$. We analytically calculate the next-to-leading order (NLO) contribution to the perturbative part of $J^P={\frac{1}{2}}^{+}$ baryon current with two identical heavy quarks, and then reanalyze the mass of ${\Xi }_{cc}^{++}$ at the NLO level. We find that the NLO correction significantly improves both scheme dependence and scale dependence, whereas it is hard to control these theoretical uncertainties at leading order. With the NLO contribution, the baryon mass is estimated to be $m_{{\Xi }_{cc}^{++}}=3.66_{-0.10}^{+0.08}\text{ GeV}$, which is consistent with the LHCb measurement.

    hep-phPRD(2019)·28 citations
13. 13*

    Stability of tetrons

    Andrzej Czarnecki🇨🇦 · Bo Leng🇨🇦 · M.B. Voloshin🇺🇸

    We consider the interactions in a mesonic system, referred here to as `tetron', consisting of two heavy quarks and two lighter antiquarks (which may still be heavy in the scale of QCD), i.e. generally $Q_a{Q}_b{\bar{q}}_c{\bar{q}}_d$, and study the existence of bound states below the threshold for decay into heavy meson pairs. At a small ratio of the lighter to heavier quark masses an expansion parameter arises for treatment of the binding in such systems. We find that in the limit where all the quarks and antiquarks are so heavy that a Coulomb-like approximation can be applied to the gluon exchange between all of them, such bound states arise when this parameter is below a certain critical value. We find the parametric dependence of the critical mass ratio on the number of colors $N_c$, and confirm this dependence by numerical calculations. In particular there are no stable tetrons when all constituents have the same mass. We discuss an application of a similar expansion in the large $N_c$ limit to realistic systems where the antiquarks are light and their interactions are nonperturbative. In this case our findings are in agreement with the recent claims from a phenomenological analysis that a stable $bb\bar{u}\bar{d}$ tetron is likely to exist, unlike those where one or both bottom quarks are replaced by the charmed quark.

    hep-phPLB(2018)·84 citations
14. 14*

    Higgs Assisted Q-balls from Pseudo-Nambu-Goldstone Bosons

    Fady Bishara🇬🇧 · George Johnson🇬🇧 · Olivier Lennon🇬🇧 · John March-Russell🇬🇧

    Motivated by recent constructions of TeV-scale strongly-coupled dynamics, either associated with the Higgs sector itself as in pseudo-Nambu-Goldstone boson (pNGB) Higgs models or in theories of asymmetric dark matter, we show that stable solitonic Q- balls can be formed from light pion-like pNGB fields carrying a conserved global quantum number in the presence of the Higgs field. We focus on the case of thick-wall Q-balls, where solutions satisfying all constraints are shown to exist over a range of parameter values. In the limit that our approximations hold, the Q-balls are weakly bound and parametrically large, and the form of the interactions of the light physical Higgs with the Q-ball is determined by the breaking of scale symmetry.

    hep-phhep-thJHEP(2017)·13 citations
15. 15*

    Superheavy dark matter through Higgs portal operators

    Rocky W. Kolb🇺🇸 · Andrew J. Long🇺🇸

    The WIMPzilla hypothesis is that the dark matter is a super-weakly-interacting and super-heavy particle. Conventionally, the WIMPzilla abundance is set by gravitational particle production during or at the end of inflation. In this study we allow the WIMPzilla to interact directly with Standard Model fields through the Higgs portal, and we calculate the thermal production (freeze-in) of WIMPzilla dark matter from the annihilation of Higgs boson pairs in the plasma. The two particle-physics model parameters are the WIMPzilla mass and the Higgs-WIMPzilla coupling. The two cosmological parameters are the reheating temperature and the expansion rate of the universe at the end of inflation. We delineate the regions of parameters space where either gravitational or thermal production is dominant, and within those regions we identify the parameters that predict the observed dark matter relic abundance. Allowing for thermal production opens up the parameter space, even for Planck-suppressed Higgs-WIMPzilla interactions.

    ↳ astro-ph.COhep-phPRD(2017)·109 citations
16. 16*

    The Importance of Quantum Pressure of Fuzzy Dark Matter on Lyman-Alpha Forest

    Jiajun Zhang🇨🇳 · Jui-Lin Kuo🇹🇼 · Hantao Liu🇨🇳 · Yue-Lin Sming Tsai🇹🇼 · Kingman Cheung🇹🇼 · Ming-Chung Chu🇨🇳

    With recent Lyman-alpha forest data from BOSS and XQ-100, some studies suggested that the lower mass limit on the fuzzy dark matter (FDM) particles is lifted up to $10^{-21}\mathrm{eV}$. However, such a limit was obtained by $\Lambda$CDM simulations with the FDM initial condition and the quantum pressure (QP) was not taken into account which could have generated non-trivial effects in large scales structures. We investigate the QP effects in cosmological simulations systematically, and find that the QP leads to further suppression of the matter power spectrum at small scales, as well as the halo mass function in the low mass end. We estimate the suppressing effect of QP in the 1D flux power spectrum of Lyman-alpha forest and compare it with data from BOSS and XQ-100. The rough uncertainties of thermal gas properties in the flux power spectrum model calculation were discussed. We conclude that more systematic studies, especially with QP taken into account, are necessary to constrain FDM particle mass using Lyman-alpha forest.

    ↳ astro-ph.COastro-ph.GAastro-ph.HEhep-phApJ(2018)·85 citations
17. 17*

    The symmetry energy in nucleon and quark matter

    Lie-Wen Chen🇨🇳

    The symmetry energy characterizes the isospin dependent part of the equation of state of isospin asymmetric strong interaction matter and it plays a critical role in many issues of nuclear physics and astrophysics. In this talk, we briefly review the current status on the determination of the symmetry energy in nucleon (nuclear) and quark matter. For nuclear matter, while the subsaturation density behaviors of the symmetry energy are relatively well-determined and significant progress has been made on the symmetry energy around saturation density, the determination of the suprasaturation density behaviors of the symmetry energy remains a big challenge. For quark matter, which is expected to appear in dense matter at high baryon densities, we briefly review the recent work about the effects of quark matter symmetry energy on the properties of quark stars and the implication of possible existence of heavy quark stars on quark matter symmetry energy. The results indicate that the $u$ and $d$ quarks could feel very different interactions in isospin asymmetric quark matter, which may have important implications on the isospin effects of partonic dynamics in relativistic heavy-ion collisions.

    ↳ nucl-thastro-ph.HEhep-phnucl-exNucl.Phys.Rev.(2017)·32 citations
18. 18*

    Axion minicluster power spectrum and mass function

    Jonas Enander🇩🇪 · Andreas Pargner🇩🇪 · Thomas Schwetz🇩🇪

    When Peccei-Quinn (PQ) symmetry breaking happens after inflation, the axion field takes random values in causally disconnected regions. This leads to fluctuations of order one in the axion energy density around the QCD epoch. These over-densities eventually decouple from the Hubble expansion and form so-called miniclusters. We present a semi-analytical method to calculate the average axion energy density, as well as the power spectrum, from the re-alignment mechanism in this scenario. Furthermore, we develop a modified Press & Schechter approach, suitable to describe the collapse of non-linear density fluctuations during radiation domination, which is relevant for the formation of axion miniclusters. It allows us to calculate the double differential distribution of gravitationally collapsed miniclusters as a function of their mass and size. For instance, assuming a PQ scale of $10^{11}$ GeV, minicluster masses range from about $5\times 10^{-16}$ to $3\times 10^{-13}$ solar masses and have sizes from about $4\times 10^4$ to $7\times 10^5$ km at the time they start to collapse.

    ↳ astro-ph.COhep-phJCAP(2017)·108 citations
19. 19*

    Open charm production in central Pb+Pb collisions at the CERN SPS: statistical model estimates

    R. V. Poberezhnyuk🇺🇦 · M. Gazdzicki🇩🇪 · M. I. Gorenstein🇺🇦

    Charm particle production in nucleus-nucleus collisions at the CERN SPS energies is considered within a statistical approach. Namely, the Statistical Model of the Early Stage is used to calculate mean multiplicity of charm particles in central Pb+Pb collisions. A small number of produced charm particles necessitates the use of the exact charm conservation law. The model predicts a rapid increase of mean charm multiplicity as a function of collision energy. The mean multiplicity calculated for central Pb+Pb collisions at the center of mass energy per nucleon pair $\sqrt{s_{NN}}=17.3$ GeV exceeds significantly the experimental upper limit. Thus, in order to describe open charm production model parameters and/or assumptions should be revised.

    ↳ nucl-thhep-phActa Phys.Polon.B(2017)·12 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.