Mon·Aug 20, 2018Monday·August 20, 2018

1. 01*

   Probing nuclear modifications of parton distribution functions through the isolated prompt photon production at the LHC

   Muhammad Goharipour🇮🇷 · S. Rostami🇮🇷

   An accurate knowledge of nuclear parton distribution functions (nPDFs) is an essential ingredient of high energy physics calculations when the processes are involving nuclei in the initial state. It is well known now that the prompt photon production both in hadronic and nuclear collisions is a powerful tool for exploring the parton densities in the nucleon and nuclei especially of the gluon. In this work, we are going to perform a comprehensive study of the isolated prompt photon production in $p$-Pb collisions at backward rapidities to find the best kinematic regions in which the experimental measurements have most sensitivity to the nuclear modifications of parton densities. Most emphasis will be placed on the antishadowing nuclear modification. To this aim, we calculate and compare various quantities at different values of center-of-mass energy covered by the LHC and also different rapidity regions to realize which one is most useful.

   hep-phhep-exPRC(2019)·9 citations
2. 02*

   Problems with Higgsplosion

   Alexander Belyaev🇬🇧 · Fedor Bezrukov🇬🇧 · Chris Shepherd🇬🇧 · Douglas Ross🇬🇧

   A recent calculation of the multi-Higgs boson production in scalar theories with spontaneous symmetry breaking has demonstrated the fast growth of the cross section with the Higgs multiplicity at sufficiently large energies, called "Higgsplosion". It was argued that "Higgsplosion" solves the Higgs hierarchy and fine-tuning problems. In our paper we argue that: a) the formula for "Higgsplosion" has a limited applicability and inconsistent with unitarity of the Standard Model; b) that the contribution from "Higgsplosion" to the imaginary part of the Higgs boson propagator cannot be re-summed in order to furnish a solution of the Higgs hierarchy and fine-tuning problems.

   hep-phhep-thPRD(2018)·21 citations
3. 03*

   Neutralino Dark Matter in Scenarios with Early Matter Domination

   Manuel Drees🇩🇪 · Fazlollah Hajkarim🇩🇪

   We investigate the production of neutralino dark matter in a cosmological scenario featuring an early matter dominated era ending at a relatively low reheating temperature. In such scenarios different production mechanisms of weakly interacting massive particles (WIMPs), besides the well--studied thermal production, can be important. This opens up new regions of parameter space where the lightest neutralino, as the best--known supersymmetric (SUSY) WIMP, obtains the required relic abundance. Many of these new sets of parameters are also compatible with current limits from colliders as well as direct and indirect WIMP searches. In particular, in standard cosmology bino--like neutralinos, which emerge naturally as lightest neutralino in many models, can have the desired relic density only in some finetuned regions of parameter space where the effective annihilation cross section is enhanced by co--annihilation or an $s-$channel pole. In contrast, if the energy density of the universe was dominated by long--lived PeV--scale particles (e.g. moduli or Polonyi fields), bino--like neutralinos can obtain the required relic density over wide regions of supersymmetric parameter space. We identify the interesting ranges of mass and decay properties of the heavy long--lived particles, carefully treating the evolution of the temperature of the thermal background.

   hep-phastro-ph.COJHEP(2018)·52 citations
4. 04*

   Chiral crystallization in an external magnetic background - Chiral spiral versus Real kink crystal -

   Hiroaki Abuki🇯🇵

   We study how an external magnetic field modifies the chiral phase structure of QCD, in particular the phases characterized by inhomogeneous chiral condensates. The magnetic field can be systematically incorporated into a generalized Ginzburg-Landau framework, and it turns out to induce a model independent universal coupling between the magnetic field and the axial isospin current. The resulting effect is found to be drastic especially in the chiral limit; no matter how small the magnetic intensity is, the tricritical Lifshitz point is totally washed out, and the real kink crystal is replaced by a magnetically induced chiral spiral. The current quark mass, on the other hand, has an opposite effect, protecting the chiral critical point from the magnetically induced chiral spiral. But once the magnetic intensity exceeds a critical value, the critical point no longer exists. We draw a semiquantitative conclusion that the critical point disappears for $\sqrt{eB}\ge 50$ MeV.

   hep-phPRD(2018)·14 citations
5. 05*

   Can SKA--Phase 1 go much beyond the LHC in supersymmetry search?

   Arpan Kar🇮🇳 · Sourav Mitra🇮🇳 · Biswarup Mukhopadhyaya🇮🇳 · Tirthankar Roy Choudhury🇮🇳

   We study the potential of the Square Kilometre Array in the first phase (SKA1) in detecting dark matter annihilation signals from dwarf spheroidals in the form of diffuse radio synchrotron. Taking the minimal supersymmetric standard model as illustration, we show that it is possible to detect such signals for dark matter masses about an order of magnitude beyond the reach of the Large Hadron Collider, with about 100 hours of observation with the SKA1.

   hep-phastro-ph.HEPRD(2019)·17 citations
6. 06*

   Interaction and Identification of the Meson-Baryon molecules

   D. P. Rathaud🇮🇳 · Ajay Kumar Rai🇮🇳

   The challenges with the molecular model of the multiquark systems are the identification of the hadronic molecules and the interaction between two color neutral hadrons. We study the di-hadronic molecular systems with proposed interaction potential as s-wave one boson exchange potential along with Screen Yukawa-like potential, and arrived with the proposal that within hadronic molecule the two color neutral hadrons experience the dipole-like interaction. The present study is the continuation of our previous study \cite{arxiv-Rathaud-penta}. With the proposed interaction potential, the mass spectra of ${\Sigma }_s{K}^{\ast }$, ${\Sigma }_c{K}^{\ast }$, ${\Sigma }_b{K}^{\ast }$, ${\Sigma }_s{D}^{\ast }$, ${\Sigma }_c{D}^{\ast }$, ${\Sigma }_b{D}^{\ast }$, ${\Sigma }_s{B}^{\ast }$, ${\Sigma }_c{B}^{\ast }$, ${\Sigma }_b{B}^{\ast }$, ${\Xi }_s{K}^{\ast }$, ${\Xi }_c{K}^{\ast }$, ${\Xi }_b{K}^{\ast }$, ${\Xi }_s{D}^{\ast }$, ${\Xi }_c{D}^{\ast }$, ${\Xi }_b{D}^{\ast }$, ${\Xi }_s{B}^{\ast }$, ${\Xi }_c{B}^{\ast }$, ${\Xi }_b{B}^{\ast }$ meson-baryon molecules are predicted. The Weinberg compositeness theorem which provides clue for the compositeness of the state is used for determination of the scattering length and effective range. The present study predict $P_c(4450)$ pentaquark sate as ${\Sigma }_c{D}^{\ast }$ molecule with $I(J^P)=\frac{1}{2}({\frac{3}{2}}^{-})$. The formalism also predicts some very interesting open as well as hidden flavour near threshold molecular pentaquark states.

   hep-phnucl-thIndian J.Phys.(2021)·17 citations
7. 07*

   New theoretical constraints on scalar color octet models

   Li Cheng🇨🇳 · Otto Eberhardt🇪🇸 · Christopher W. Murphy🇺🇸

   We study theoretical constraints on a model whose scalar sector contains one color octet and one or two color singlet $SU(2{)}_L$ doublets. Using the unitarity of the theory, we constrain the parameters of the scalar potential for the first time at next-to-leading order in perturbation theory. We also derive new conditions guaranteeing the stability of the potential. We use the HEPfit package to single out the viable parameter regions at the electroweak scale and test the stability of the renormalization group evolution up to the multi-TeV region. Additionally, we set upper limits on the scalar mass splittings. All results are given for both cases, with and without a second scalar color singlet.

   hep-phCPC(2019)·18 citations
8. 08*

   3-loop gauge coupling for hot gauge theories

   York Schroder🇨🇱

   This talk offers a brief review of the determination of coupling constants in the framework of dimensionally reduced effective field theories for thermal QCD, specializing on its gluonic sector. Interestingly, higher-order operators that go beyond the usual super-renormalizable truncation of the effective theory need to be considered when matching parameters at three loops.

   hep-phPoS(2018)·0 citations
9. 09*

   Model-Independent Determination of $B_c^{+}\to {\eta }_c{\ell }^{+}\nu$ Form Factors

   Christopher W. Murphy🇺🇸 · Amarjit Soni🇺🇸

   We derive model-independent bounds on the form factors for the decay $B_c^{+}\to {\eta }_c{\ell }^{+}\nu$ including full mass effects, i.e. $\ell =e,\mu ,\text{ and }\tau$. The bounds are obtained by using the BGL parameterization for the form factors, and fitting to the preliminary lattice data of the HPQCD Collaboration. Our main result after bounding the form factors is the Standard Model (SM) prediction for the ratio of branching fractions $R({\eta }_c)=\mathcal{B}(B_c^{+}\to {\eta }_c{\tau }^{+}{\nu }_{\tau })/\mathcal{B}(B_c^{+}\to {\eta }_c{\mu }^{+}{\nu }_{\mu })$. We find $R({\eta }_c){|}_{\text{SM}}=0.31_{-0.02}^{+0.04}$, and argue that a measurement of $R({\eta }_c)$ is within the reach of LHCb during the high luminosity run of the LHC. In addition, using the heavy-quark spin symmetry of the $B_c$ meson we relate our results for $B_c^{+}\to {\eta }_c{\ell }^{+}\nu$ to those for $B_c^{+}\to J/\psi {\ell }^{+}\nu$ yielding the estimate $R(J/\psi ){|}_{\text{SM}}=0.26\pm 0.02$ in good agreement with other determinations.

   hep-phhep-exPRD(2018)·25 citations
10. 10*

    SMEFT Corrections to $Z$ Boson Decays

    Sally Dawson🇺🇸 · Ahmed Ismail🇺🇸

    We compute the one-loop corrections to $Z$ decay properties from dimension-6 operators in the Standard Model Effective Field Theory (SMEFT) that contribute also to anomalous 3-gauge boson couplings and examine the relative sensitivity of the two processes to the anomalous couplings. The size of the contributions is of order a few percent, of the same size as Standard Model electroweak corrections. This is part of a program of computing electroweak quantities to one-loop in the SMEFT: these calculations are needed for a future global fit to limit the coefficients of the dimension-six Wilson coefficients consistently at one loop.

    hep-phPRD(2018)·39 citations
11. 11*

    Reconciling the Diversity and Uniformity of Galactic Rotation Curves with Self-Interacting Dark Matter

    Tao Ren🇺🇸 · Anna Kwa🇺🇸 · Manoj Kaplinghat🇺🇸 · Hai-Bo Yu🇺🇸

    Galactic rotation curves exhibit diverse behavior in the inner regions, while obeying an organizing principle, i.e., they can be approximately described by a radial acceleration relation or the Modified Newtonian Dynamics phenomenology. We analyze the rotation curve data from the SPARC sample, and explicitly demonstrate that both the diversity and uniformity are naturally reproduced in a hierarchical structure formation model with the addition of dark matter self-interactions. The required concentrations of the dark matter halos are fully consistent with the concentration-mass relation predicted by the Planck cosmological model. The inferred stellar mass-to-light ($3.6\mu m$) ratios scatter around $0.5M_{\odot }/L_{\odot }$, as expected from population synthesis models, leading to a tight radial acceleration relation and baryonic Tully-Fisher relation. The inferred stellar-halo mass relation is consistent with the expectations from abundance matching. These results indicate that the inner dark matter halos of galaxies are thermalized due to the self-interactions of dark matter particles.

    ↳ astro-ph.GAastro-ph.COhep-phPRX(2019)·194 citations
12. 12*

    Inconsistencies of higgsplosion

    Alexander Monin🇨🇭

    It is shown that higgsplosion scenario is impossible within local QFT framework.

    ↳ hep-thhep-phmath-phmath.MP27 citations
13. 13*

    Strong constraints on clustered primordial black holes as dark matter

    Torsten Bringmann🇳🇴 · Paul Frederik Depta🇩🇪 · Valerie Domcke🇩🇪 · Kai Schmidt-Hoberg🇩🇪

    The idea of dark matter in the form of primordial black holes has seen a recent revival triggered by the LIGO detection of gravitational waves from binary black hole mergers. In this context, it has been argued that a large initial clustering of primordial black holes can help alleviate the strong constraints on this scenario. In this work, we show that on the contrary, with large initial clustering the problem is exacerbated and constraints on primordial black hole dark matter become overwhelmingly strong.

    ↳ astro-ph.COhep-phPRD(2019)·67 citations
14. 14*

    Improving Statistical Sensitivity of X-ray Searches for Axion-Like Particles

    Joseph P. Conlon🇬🇧 · Markus Rummel🇨🇦

    X-ray observations of bright AGNs in or behind galaxy clusters offer unique capabilities to constrain axion-like particles (ALPs). Existing analysis technique rely on measurements of the global goodness-of-fit. We develop a new analysis methodology that improves the statistical sensitivity to ALP-photon oscillations by isolating the characteristic quasi-sinusoidal modulations induced by ALPs. This involves analysing residuals in wavelength space allowing the Fourier structure to be made manifest as well as a machine learning approach. For telescopes with microcalorimeter resolution, simulations suggest these methods give an additional factor of two in sensitivity to ALPs compared to previous approaches.

    ↳ astro-ph.COastro-ph.HEhep-phMNRAS(2019)·13 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.