Thu·May 10, 2018Thursday·May 10, 2018

1. 01*

   Matter effects in neutrino visible decay at future long-baseline experiments

   M. V. Ascencio-Sosa🇵🇪 · A. M. Calatayud-Cadenillas🇵🇪 · A. M. Gago🇵🇪 · J. Jones-Pérez🇵🇪

   Neutrino visible decay in the presence of matter is re-evaluated. We study these effects in two future long-baseline experiments where matter effects are relevant: DUNE (1300 km) and a hypothetical beam aimed towards ANDES (7650 km). We find that matter effects are negligible for the visible component of neutrino decay at DUNE, being much more relevant at ANDES. We perform a detailed simulation of DUNE, considering ${\nu }_{\mu }$ disappearance and ${\nu }_e$ appearance channels, for both FHC and RHC modes. The sensitivity to the decay constant ${\alpha }_3$ can be as low as $2\times 10^{-6}$ eV${}^2$ at 90% C.L., depending on the neutrino masses and type of coupling. We also show the impact of neutrino decay in the determination of ${\theta }_{23}$ and ${\delta }_{\mathrm{CP}}$, and find that the best-fit value of ${\theta }_{23}$ can move from a true value at the lower octant towards the higher octant.

   hep-phEPJC(2018)·33 citations
2. 02*

   Doubly charmed ${\Xi }_{cc}$ molecular states from meson-baryon interaction

   J. M. Dias🇪🇸 · V. R. Debastiani🇪🇸 · J.-Jun Xie🇨🇳 · E. Oset🇪🇸

   Stimulated by the new experimental LHCb findings associated with the ${\Omega }_c$ states, some of which we have described in a previous work as being dynamically generated through meson-baryon interaction, we have extended this approach to make predictions for new ${\Xi }_{cc}$ molecular states in the $C=2$, $S=0$ and $I=1/2$ sector. These states manifest themselves as poles in the solution of the Bethe-Salpeter equation in coupled channels. The kernels of this equation were obtained using the Lagrangians coming from the hidden local gauge symmetry, where the interactions are dominated by the exchange of light vector mesons. The extension of this approach to the heavy sector stems from the realization that the dominant interaction corresponds to having the heavy quarks as spectators, which implies the preservation of the heavy quark symmetry. As a result, we get several states: two states from the pseudoscalar meson-baryon interaction with $J^P=1/2^{-}$, and masses around $4080$ and $4090$ MeV, and one at $4150$ MeV for $J^P=3/2^{-}$. Furthermore, from the vector meson-baryon interaction we get three states degenerate with $J^P=1/2^{-}$ and $3/2^{-}$ from $4220$ MeV to $4330$ MeV, and two more states around $4280$ MeV and $4410$ MeV, degenerate with $J^P=1/2^{-},3/2^{-}$ and $5/2^{-}$.

   hep-phPRD(2018)·33 citations
3. 03*

   Leptonic Dark Matter with Scalar Dilepton Mediator

   Ernest Ma (UC Riverside)🇺🇸

   A simple and elegant mechanism is proposed to resolve the problem of having a light scalar mediator for self-interacting dark matter and the resulting disruption to the cosmic microwave background (CMB) at late times by the former's enhanced Sommerfeld production and decay. The crucial idea is to have Dirac neutrinos with the conservation of U(1) lepton number extended to the dark sector. The simplest scenario consists of scalar or fermion dark matter with unit lepton number accompanied by a light scalar dilepton mediator, which decays to two neutrinos.

   hep-phMod.Phys.Lett.A(2018)·7 citations
4. 04*

   Kinetic freeze-out properties from transverse momentum spectra of pions in high energy proton-proton collisions

   Li-Li Li🇨🇳 · Fu-Hu Liu🇨🇳

   Transverse momentum spectra of negative and positive pions produced at mid-(pseudo)rapidity in inelastic or non-single-diffractive proton-proton collisions over a center-of-mass energy, $\sqrt{s}$, range from a few GeV to above 10 TeV are analyzed by the blast-wave fit with Boltzmann (Tsallis) distribution. The blast-wave fit results are well fitting to the experimental data measured by several collaborations. In a particular superposition with Hagedorn function, both the excitation functions of kinetic freeze-out temperature ($T_0$) of emission source and transverse flow velocity (${\beta }_T$) of produced particles obtained from a given selection in the blast-wave fit with Boltzmann distribution have a hill at $\sqrt{s}\approx 10$ GeV, a drop at dozens of GeV, and then an increase from dozens of GeV to above 10 TeV. However, both the excitation functions of $T_0$ and ${\beta }_T$ obtained in the blast-wave fit with Tsallis distribution do not show such a complex structure, but a very low hill. In another selection for the parameters or in the superposition with the usual step function, $T_0$ and ${\beta }_T$ increase generally quickly from a few GeV to about 10 GeV and then slightly at above 10 GeV, there is no such the complex structure, when also studying nucleus-nucleus collisions.

   hep-phhep-exnucl-exnucl-thMDPI Physics(2020)·17 citations
5. 05*

   Electromagnetic couplings of radially excited light vector mesons from QCD sum rules

   S. S. Afonin🇷🇺 · T. D. Solomko🇷🇺

   The couplings of unflavored vector mesons to the $e^{+}{e}^{-}$ annihilation are an important source of information on the nature and structure of these resonances which play a prominent role in the hadron phenomenology. The couplings of many radially excited heavy vector mesons are measured, while the corresponding couplings for light vector mesons are not known. We propose a phenomenological method allowing to estimate these unknown couplings. The method is suggested by our observation that the electromagnetic coupling of the $n$-th radial excitation of $S$-wave heavy vector meson decouples from the $e^{+}{e}^{-}$ annihilation with nearly exponential rate with $n$. It becomes natural to assume that the same effect takes place in the light vector mesons and this would allow to estimate the unknown couplings. We tested this assumption with the help of a generalized version of borelized QCD spectral sum rules saturated by a linear radial trajectory of meson states taken from the phenomenology. This leads to a consistent setup which is able to predict the decoupling rate. The calculated rate turned out to be almost the same as in the heavy vector mesons. Our result may be interpreted as an effective account for non-trivial electromagnetic formfactor in meson decays to $e^{+}{e}^{-}$, thus looking beyond the large-$N_c$ limit. On the one hand, we argue that the given decoupling does not necessary contradict to the previous large-$N_c$ results for the Regge like meson spectra.

   hep-phnucl-thEur.Phys.J.Plus(2019)·4 citations
6. 06*

   Indirect measurement of triple-Higgs coupling at an electron-positron collider with polarized beams

   Saurabh D. Rindani🇮🇳 · Balbeer Singh🇮🇳

   We examine the possibility of using single-Higgs production at an $e^{+}{e}^{-}$ collider with polarized beams to measure, or constrain, indirectly a possible anomalous triple-Higgs coupling, which can contribute to the process via one-loop diagrams. In the dominant process $e^{+}{e}^{-}\to ZH$, longitudinally polarized beams can lead to an improvement in the cross section by 50\% for $e^{-}$ and $e^{+}$ polarizations of $-0.8$ and $+0.3$, respectively. This corresponds to an improvement in the sensitivity to the triple-Higgs coupling of about 18\% for a centre-of-mass energy of 250 GeV and an integrated luminosity of 2 ab${}^{-1}$, making a strong case of beam polarization. This also implies that with polarized beams, the luminosity needed to get a particular sensitivity is less by about 33\% as compared to that needed with unpolarized beams. Even when only the $e^{-}$ beam is polarized $-0.8$, the improvement in the sensitivity is about 8\%. We also study the effect of longitudinal beam polarization on the sensitivity to the triple-Higgs coupling of Higgs production through the subdominant process $e^{+}{e}^{-}\to H\nu \bar{\nu }$ occurring through $WW$ fusion.

   hep-phhep-exInt.J.Mod.Phys.A(2020)·6 citations
7. 07*

   Approximate Hamiltonian for baryons in heavy-flavor QCD

   Kamil Serafin🇵🇱 · María Gómez-Rocha🇦🇹 · Jai More🇮🇳 · Stanisław D. Głazek🇵🇱

   Aiming at relativistic description of gluons in hadrons, the renormalization group procedure for effective particles (RGPEP) is applied to baryons in QCD of heavy quarks. The baryon eigenvalue problem is posed using the Fock-space Hamiltonian operator obtained by solving the RGPEP equations up to second order in powers of the coupling constant. The eigenstate components that contain three quarks and two or more gluons are heuristically removed at the price of inserting a gluon-mass term in the component with one gluon. The resulting problem is reduced to the equivalent one for the component of three quarks and no gluons. Each of the three quark-quark interaction terms thus obtained consists of a spin-dependent Coulomb term and a spin-independent harmonic oscillator term. Quark masses are chosen to fit the lightest spin-one quarkonia masses most accurately. The resulting estimates for bbb and ccc states match estimates obtained in lattice QCD and in quark models. Masses of ccb and bbc states are also estimated. The corresponding wave functions are invariant with respect to boosts. In the ccb states, charm quarks tend to form diquarks. The accuracy of our approximate Hamiltonian can be estimated through comparison by including components with two gluons within the same method.

   hep-phhep-thEPJC(2018)·43 citations
8. 08*

   Probing the Effects of Dimension-eight Operators Describing Anomalous Neutral Triple Gauge Boson Interactions at FCC-hh

   A. Senol🇹🇷 · H. Denizli🇹🇷 · A. Yilmaz🇹🇷 · I. Turk Cakir🇹🇷 · K.Y. Oyulmaz🇹🇷 · O. Karadeniz🇹🇷 · O. Cakir🇹🇷

   The effects of dimension-eight operators giving rise to anomalous neutral triple gauge boson interactions of $Z\gamma \gamma$ and $Z\gamma Z$ vertices in $pp\to l^{-}{l}^{+}\gamma$ and $pp\to \nu \bar{\nu }\gamma$ are investigated at 100 TeV centre of mass energy of future circular hadron collider (FCC-hh). The transverse momentum of photon, invariant mass of $l^{-}{l}^{+}\gamma$ and angular distribution of charged lepton in the rest frame of $l^{-}{l}^{+}$ and Missing Energy Transverse (MET) are considered in the analysis. The realistic detector effects are also included with Delphes simulation. Sensitivity limits obtained at 95\% C.L. for $C_{\tilde{B}W}/{\Lambda }^4$ and $C_{BB}/{\Lambda }^4$ couplings are $[-0.52;0.52]([-0.40;0.40])$ TeV${}^{-4}$, $[-0.43;0.43]([-0.33;0.33])$ TeV${}^{-4}$ in the dilepton+photon channel and $[-0.11;0.11]([-0.084;0.084])$ TeV${}^{-4}$, $[-0.092;0.092]([-0.072;0.072])$ TeV${}^{-4}$ in the MET+photon channel with $L_{int}$=1 (3) ab${}^{-1}$, respectively.

   hep-phNPB(2018)·41 citations
9. 09*

   Study on the resonant parameters of $Y(4220)$ and $Y(4390)$

   Jielei Zhang🇨🇳 · Limin Yuan🇨🇳 · Rumin Wang🇨🇳

   Many vector charmonium-like states have been reported recently in the cross sections of $e^{+}{e}^{-}\to \omega {\chi }_{c0}$, ${\pi }^{+}{\pi }^{-}{h}_c$, ${\pi }^{+}{\pi }^{-}J/\psi$, ${\pi }^{+}{\pi }^{-}\psi (3686)$ and ${\pi }^{+}{D}^0{D}^{\ast -}+c.c.$ To better understand the nature of these states, a combined fit is performed to these cross sections by using three resonances $Y(4220)$, $Y(4390)$ and $Y(4660)$. The resonant parameters for the three resonances are obtained. We emphasize that two resonances $Y(4220)$ and $Y(4390)$ are sufficient to explain these cross sections below 4.6 GeV. The lower limits of $Y(4220)$ and $Y(4390)$'s leptonic decay widths are also determined to be $(36.4\pm 2.0\pm 4.2)$ and $(123.8\pm 6.5\pm 9.0)$ eV.

   hep-phhep-exAdv.High Energy Phys.(2018)·8 citations
10. 10*

    Decay mechanisms in bound state interaction kernels

    A.S. Miramontes🇦🇹 · H. Sanchis-Alepuz🇦🇹

    We present progress on the study of decay-channel effects in the properties of hadrons using covariant Bethe-Salpeter equations (BSEs). The main goal will be to develop BSE kernels that contain explicit decay mechanisms. This will be first explored in the meson sector where, for example, a kernel suitable to study the rho meson should contain a virtual $\rho \to \pi +\pi$ decay mechanism. This will be tackled by including explicit pion degrees of freedom in addition to quarks and gluons.

    hep-phActa Phys.Polon.Supp.(2018)·5 citations
11. 11*

    The Power of Genetic Algorithms: what remains of the pMSSM?

    Steven Abel🇬🇧 · David G. Cerdeno🇬🇧 · Sandra Robles🇦🇺

    Genetic Algorithms (GAs) are explored as a tool for probing new physics with high dimensionality. We study the 19-dimensional pMSSM, including experimental constraints from all sources and assessing the consistency of potential signals of new physics. We show that GAs excel at making a fast and accurate diagnosis of the cross-compatibility of a set of experimental constraints in such high dimensional models. In the case of the pMSSM, it is found that only $\mathcal{O}(10^4)$ model evaluations are required to obtain a best fit point in agreement with much more costly MCMC scans. This efficiency allows higher dimensional models to be falsified, and patterns in the spectrum identified, orders of magnitude more quickly. As examples of falsification, we consider the muon anomalous magnetic moment, and the Galactic Centre gamma-ray excess observed by Fermi-LAT, which could in principle be explained in terms of neutralino dark matter. We show that both observables cannot be explained within the pMSSM, and that they provide the leading contribution to the total goodness of the fit, with ${\chi }_{\delta a_{\mu }^{\mathrm{SUSY}}}^2\approx 12$ and ${\chi }_{\mathrm{GCE}}^2\approx 155$, respectively.

    hep-phastro-ph.COcs.NE35 citations
12. 12*

    Dark Matter as a remnant of SQCD Inflation

    Subhaditya Bhattacharya (IIT Guwahati)🇮🇳 · Abhijit Kumar Saha (IIT Guwahati)🇮🇳 · Arunansu Sil (IIT Guwahati)🇮🇳 · Jose Wudka (UC Riverside)🇺🇸

    We propose a strongly coupled supersymmetric gauge theory that can accommodate both the inflation (in the form of generalized hybrid inflation) and dark matter (DM). In this set-up, we identify the DM as the Goldstones associated with the breaking of a global symmetry ($SU(4)\times SU(4)\to SU(4)$) after inflation ends. Due to the non-abelian nature of this symmetry, the scenario provides with multiple DMs. We then construct a low energy theory which generates a Higgs portal like coupling of the DMs with Standard Model (SM), thus allowing them to thermally freeze out. While the scales involved in the inflation either have a dynamical origin or related to UV interpretation in terms of a heavy quark field in the supersymmetric QCD (SQCD) sector, the DM masses however are generated from explicit breaking of the chiral symmetry of the SQCD sector. We discuss DM phenomenology for both degenerate and non-degenerate cases, poised with DM-DM interactions and find allowed region of parameter space in terms of relic density and direct search constraints.

    hep-phJHEP(2018)·10 citations
13. 13*

    Vacuum stabilized by anomalous magnetic moment

    Stefan Evans🇺🇸 · Johann Rafelski (Arizona)🇺🇸

    An analytical result for Euler-Heisenberg effective action, valid for electron spin $g-$factor $|g|<2$, was extended to the domain $|g|>2$ via discovered periodicity of the effective action. This allows for a simplified computation of vacuum instability modified by the electrons measured $g=2.002319$. We find a strong suppression of vacuum decay into electron positron pairs when magnetic fields are dominant. The result is reminiscent of mass catalysis by magnetic fields.

    hep-phnucl-thPRD(2018)·9 citations
14. 14*

    Some results on Lepton Flavour Universality Violation

    Jorge Alda🇪🇸 · Jaume Guasch🇪🇸 · Siannah Peñaranda🇪🇸

    Motivated by recent experimental measurements on flavour physics, in tension with Standard Model predictions, we perform an updated analysis of New Physics violating Lepton Flavour Universality, by using the effective Lagrangian approach and in the Z' and S_3 leptoquark models. We explicitly analyze the impact of considering complex Wilson coefficients in the analysis of B-anomalies, by performing a global fit of R_K and R_K*0 observables, together with \Delta Ms and A_CP^mix. The inclusion of complex couplings provides a slightly improved global fit, and a marginally improved \Delta Ms prediction.

    hep-phEPJC(2019)·19 citations
15. 15*

    Small-scale structure from neutron dark decay

    Georgios K. Karananas🇩🇪 · Alexis Kassiteridis🇩🇪

    It was recently proposed that the disagreement in the experimental measurements of the lifetime of the neutron might be eradicated if the neutron decays to particles responsible for the dark matter in the Universe. In this paper we construct a proto- type self-interacting dark matter model which, apart from reproducing the correct relic abundance, resolves all small-scale problems of the $\Lambda$CDM paradigm. The theory is compatible with all present cosmological observations and astrophysical bounds.

    hep-phastro-ph.COJCAP(2018)·31 citations
16. 16*

    Magnetic monopoles with internal structure

    D. Bazeia🇧🇷 · M.A. Marques🇧🇷 · R. Menezes🇧🇷

    We investigate the presence of magnetic monopoles in a model that extends the non Abelian model originally studied by 't Hooft and Polyakov with the inclusion of an extra neutral field. The investigation includes modifications of the dynamics of the gauged fields, and the main results unveil a route to construct solutions that engender internal structure and live in a compact space.

    ↳ hep-thhep-phnlin.PSPRD(2018)·28 citations
17. 17*

    Joint $R_{AA}$ and $v_2$ predictions for $Pb+Pb$ collisions at the LHC within DREENA-C framework

    Dusan Zigic🇷🇸 · Igor Salom🇷🇸 · Jussi Auvinen🇷🇸 · Marko Djordjevic🇷🇸 · Magdalena Djordjevic🇷🇸

    In this paper, we presented our recently developed DREENA-C framework, which is a fully optimized computational suppression procedure based on our state-of-the-art dynamical energy loss formalism in constant temperature finite size QCD medium. With this framework, we for the first time, generated joint $R_{AA}$ and $v_2$ predictions within our dynamical energy loss formalism. The predictions are generated for both light and heavy flavor probes, and different centrality regions in $Pb+Pb$ collisions at the LHC, and compared with the available experimental data. Despite the fact that DREENA-C does not contain medium evolution (to which $v_2$ is largely sensitive) and the fact that other approaches faced difficulties in explaining $v_2$ data, we find that DREENA-C leads to qualitatively good agreement with this data, though quantitatively, the predictions are visibly above the experimental data. Intuitive explanation behind such results is presented, supporting the validity of our model, and it is expected that introduction of evolution in the ongoing improvement of DREENA framework, will lead to better joint agreement with $R_{AA}$ and $v_2$ data, and allow better understanding of the underlying QCD medium.

    ↳ nucl-thhep-phJ.Phys.G(2019)·38 citations
18. 18*

    Higher Order Clockwork Gravity

    Florian Niedermann🇬🇧 · Antonio Padilla🇬🇧 · Paul M. Saffin🇬🇧

    We present a higher order generalisation of the clockwork mechanism starting from an underlying non-linear multigravity theory with a single scale and nearest neighbour ghost-free interactions. Without introducing any hierarchies in the underlying potential, this admits a family of Minkowski vacua around which massless graviton fluctuations couple to matter exponentially more weakly than the heavy modes. Although multi-diffeomorphisms are broken to the diagonal subgroup in our theory, an asymmetric distribution of conformal factors in the background vacua translates this diagonal symmetry into an asymmetric shift of the graviton gears. In particular we present a TeV scale multigravity model with $\mathcal{O}(10)$ sites that contains a massless mode whose coupling to matter is Planckian, and a tower of massive modes starting at a TeV mass range and with TeV strength couplings. This suggests a possible application to the hierarchy problem as well as a candidate for dark matter.

    ↳ hep-thgr-qchep-phPRD(2018)·21 citations
19. 19*

    Primordial Black Holes from Sound Speed Resonance during Inflation

    Yi-Fu Cai🇨🇳 · Xi Tong🇨🇳 · Dong-Gang Wang🇳🇱 · Sheng-Feng Yan🇨🇳

    We report on a novel phenomenon of the resonance effect of primordial density perturbations arisen from a sound speed parameter with an oscillatory behavior, which can generically lead to the formation of primordial black holes in the early Universe. For a general inflaton field, it can seed primordial density fluctuations and their propagation is governed by a parameter of sound speed square. Once if this parameter achieves an oscillatory feature for a while during inflation, a significant non-perturbative resonance effect on the inflaton field fluctuations takes place around a critical length scale, which results in significant peaks in the primordial power spectrum. By virtue of this robust mechanism, primordial black holes with specific mass function can be produced with a sufficient abundance for dark matter in sizable parameter ranges.

    ↳ astro-ph.COgr-qchep-phhep-thPRL(2018)·197 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.