Tue·Sep 5, 2017Tuesday·September 5, 2017

1. 01*

   Closing the window on $\sim$GeV Dark Matter with moderate ($\sim$$\mu$b) interaction with nucleons

   M. Shafi Mahdawi🇺🇸 · Glennys R. Farrar🇺🇸

   We improve limits on the spin-independent scattering cross section of Dark Matter on nucleons, for DM in the 300 MeV -- 100 GeV mass range, based on the DAMIC and XQC experiments. Our results close the window which previously existed in this mass range, for a DM-nucleon cross section of order $\approx \mu$b, assuming the standard velocity distribution.

   hep-phastro-ph.HEJCAP(2017)·57 citations
2. 02*

   Asymmetric dark matter with a possible Bose-Einstein condensate

   S. HajiSadeghi🇺🇸 · S. Smolenski🇺🇸 · J. Wudka🇺🇸

   We investigate the properties of a Bose gas with a conserved charge as a dark matter candidate, taking into account the restrictions imposed by relic abundance, direct and indirect detection limits, big-bang nucleosynthesis and large scale structure formation constraints. We consider both the WIMP-like scenario of dark matter masses $\gtrsim$ 1 GeV, and the small mass scenario, with masses $\lesssim 10^{-11}$ eV. We determine that a Bose-Einstein condensate will be present at sufficiently early times, but only for the small-mass scenario it will remain at the present epoch.

   hep-phPRD(2019)·14 citations
3. 03*

   Characterizing dark matter at the LHC in Drell-Yan events

   Rodolfo M. Capdevilla🇺🇸 · Antonio Delgado🇺🇸 · Adam Martin🇺🇸 · Nirmal Raj🇺🇸

   Spectral features in LHC dileptonic events may signal radiative corrections coming from new degrees of freedom, notably dark matter and mediators. Using simplified models, we show how these features can reveal the fundamental properties of the dark sector, such as self-conjugation, spin and mass of dark matter, and the quantum numbers of the mediator. Distributions of both the invariant mass $m_{\ell \ell }$ and the Collins-Soper scattering angle $cos{\theta }_{CS}$ are studied to pinpoint these properties. We derive constraints on the models from LHC measurements of $m_{\ell \ell }$ and $cos{\theta }_{CS}$, which are competitive with direct detection and jets + Missing Energy searches. We find that in certain scenarios the $cos{\theta }_{CS}$ spectrum provides the strongest bounds, underlying the importance of scattering angle measurements for non-resonant new physics.

   hep-phPRD(2018)·12 citations
4. 04*

   Strange mechanics of the neutrino flavor pendulum

   Lucas Johns🇺🇸 · George M. Fuller🇺🇸

   We identify in the flavor transformation of astrophysical neutrinos a new class of phenomena, a common outcome of which is the suppression of flavor conversion. Appealing to the equivalence between a bipolar neutrino system and a gyroscopic pendulum, we find that these phenomena have rather striking interpretations in the mechanical picture: in one instance, the gyroscopic pendulum initially precesses in one direction, then comes to a halt and begins to precess in the opposite direction---a counterintuitive behavior that we analogize to the motion of a toy known as a rattleback. We analyze these behaviors in the early universe, wherein a chance connection to sterile neutrino dark matter emerges, and we briefly suggest how they might manifest in compact-object environments.

   hep-phastro-ph.COastro-ph.HEPRD(2018)·26 citations
5. 05*

   Study of $B_c^{+}$ decays to the $K^{+}{K}^{-}{\pi }^{+}$ final state by using $B_s^0$, ${\chi }_{c0}$ and $D^0$ resonances and weak annihilation nonresonant topologys

   Behnam Mohammadi🇮🇷

   In this research the weak decay of $B_c^{+}$ decays to the $K^{+}{K}^{-}{\pi }^{+}$ final state, which is observed by LHCb collaboration for the first time, is calculated in the quasi-two-body decays which takes into account the $B_s^0$, ${\chi }_{c0}$ and $D^0$ resonances and weak annihilation nonresonant contributions. In this process, the $B_c^{+}$ meson decays first into $B_s^0{\pi }^{+}$, ${\chi }_{c0}{\pi }^{+}$ and $D^0{\pi }^{+}$ intermediate states, and then the $B_s^0$, ${\chi }_{c0}$ and $D^0$ resonances decay into $K^{+}{K}^{-}$ components, which undergo final state interaction. The mode of the $B_c^{+}\to D^0(\to K^{-}{\pi }^{+})K^{+}$ is also associated to the calculation, in this mode the intermediate resonance $D^0$ decays to the $K^{-}{\pi }^{+}$ final mesons. The resonances $B_s^0$, ${\chi }_{c0}$ and $D^0$ effects in the $B_c^{+}\to B_s^0(\to K^{+}{K}^{-}){\pi }^{+}$, $B_c^{+}\to {\chi }_{c0}(\to K^{+}{K}^{-}){\pi }^{+}$ and $B_c^{+}\to D^0(\to K^{+}{K}^{-}){\pi }^{+},D^0(\to K^{-}{\pi }^{+})K^{+}$ decays are described in terms of the quasi-two-body modes. There is a weak annihilation nonresonant contribution in which $B_c^{+}$ decays to the $K^{+}{K}^{-}{\pi }^{+}$ directly, so the point-like 3-body matrix element $⟨K^{+}{K}^{-}{\pi }^{+}|u\bar{d}|0⟩$ is also considered. The decay mode of the $B_c^{+}\to {\bar{K}}^{\ast 0}(892)K^{+}$ is contributed to the annihilation contribution. The branching ratios of quasi-two-body decays expand in the range from $1.98\times 10^{-6}$ to $7.32\times 10^{-6}$.

   hep-phJHEP(2017)·7 citations
6. 06*

   Helicity Amplitudes for production of massive gravitino/goldstino

   Bryan O. Larios🇲🇽

   The spinor helicity formalism (SHF) has been efficiently applied to compute perturbative amplitudes in plenty of processes and reactions in gauge theories (including gravity), mostly in the massless case. Some work has been done in order to extend the SHF to the massive case. We have used these powerful tools to evaluate amplitudes in a local supersymmetric model where the gravitino is the lightest supersymmetric particle (LSP). Two decays have been evaluated in order to show the capability of the SHF in the massive extension, namely the two body neutralino decays ${\tilde{\chi }}_0\to V{\tilde{\Psi }}^{\mu }$ with $V=\gamma ,Z$. The comparisons of amplitudes with spin-3/2 gravitino and spin-1/2 goldstino are also presented.

   hep-phhep-thJ.Phys.Conf.Ser.(2017)·0 citations
7. 07*

   Double Elementary Goldstone Higgs Boson Production in Future Linear Colliders

   Yu-Chen Guo🇨🇳 · Chong-Xing Yue🇨🇳 · Zhi-Cheng Liu🇨🇳

   The Elementary Goldstone Higgs (EGH) model is a perturbative extension of the standard model (SM), which identifies the EGH boson as the observed Higgs boson. In this paper, we study pair production of the EGH boson in future linear electron positron colliders. The cross sections in the TeV region can be changed to about $-27\%$, $163\%$ and $-34\%$ for the $e^{+}{e}^{-}\to Zhh$, $e^{+}{e}^{-}\to \nu \bar{\nu }hh$, and $e^{+}{e}^{-}\to t\bar{t}hh$ processes with respect to the SM predictions, respectively. According to the expected measurement precisions, such correction effects might be observed in future linear colliders. In addition, we compare the cross sections of double SM-like Higgs boson production with the predictions in other new physics models.

   hep-phInt.J.Mod.Phys.A(2018)·2 citations
8. 08*

   Study of $P$-wave excitations of observed charmed strange baryons

   Dan-Dan Ye🇨🇳 · Ze Zhao🇨🇳 · Ailin Zhang🇨🇳

   Many excited charmed strange baryons such as ${\Xi }_c(2790)$, ${\Xi }_c(2815)$, ${\Xi }_c(2930)$, ${\Xi }_c(2980)$, ${\Xi }_c(3055)$, ${\Xi }_c(3080)$ and ${\Xi }_c(3123)$ have been observed. In order to understand their internal structure and to determine their spin-parities, the strong decay properties of these baryons as possible $P$-wave excited ${\Xi }_c$ candidates have been systematically studied in a ${}^3{P}_0$ model. The configurations and $J^P$ assignments of ${\Xi }_c(2790)$, ${\Xi }_c(2815)$, ${\Xi }_c(2930)$, ${\Xi }_c(2980)$, ${\Xi }_c(3055)$, ${\Xi }_c(3080)$ and ${\Xi }_c(3123)$ have been explored based on recent experimental data. In our analyses, ${\Xi }_c(3055)$, ${\Xi }_c(3080)$ and ${\Xi }_c(3123)$ seem impossible to be the $P$-wave excited ${\Xi }_c$. ${\Xi }_c(2790)$, ${\Xi }_c(2815)$, ${\Xi }_c(2930)$ and ${\Xi }_c(2980)$ may be the $P$-wave excited ${\Xi }_c$. In particular, ${\Xi }_c(2790)$ and ${\Xi }_c(2815)$ are very possibly the $P$-wave excited ${\Xi }_{c1}(1/2^{-})$ and ${\Xi }_{c1}(3/2^{-})$, respectively. ${\Xi }_c(2980)$ may be the $P$-wave excited ${\Xi }_{c1}^{{}^{\prime }}({\frac{1}{2}}^{-})$. ${\Xi }_c(2930)$ may be the $P$-wave ${\Xi }_{c0}^{{}^{\prime }}({\frac{1}{2}}^{-})$, ${\tilde{\Xi }}_{c0}({\frac{1}{2}}^{-})$, ${\Xi }_{c2}^{{}^{\prime }}({\frac{3}{2}}^{-})$, ${\Xi }_{c2}^{{}^{\prime }}({\frac{5}{2}}^{-})$, ${\tilde{\Xi }}_{c2}({\frac{3}{2}}^{-})$ or ${\tilde{\Xi }}_{c2}({\frac{5}{2}}^{-})$. Furthermore, some branching fraction ratios related to the internal structure and quark configuration of $P$-wave ${\Xi }_c$ have also been computed. Measurements of these ratios in the future will be helpful to understand these excited ${\Xi }_c$.

   hep-phPRD(2017)·43 citations
9. 09*

   A model of vector leptoquarks in view of the $B$-physics anomalies

   Lorenzo Calibbi🇨🇳 · Andreas Crivellin🇨🇭 · Tianjun Li🇨🇳

   Lepton number as a fourth color is an intriguing theoretical idea which is combined with a possible left-right symmetry within the famous Pati-Salam (PS) model. In the conventional PS model, a spontaneous breaking of the PS gauge group down to the SM one can only take place at very high scales (above the PeV scale) due to the stringent bounds from $K_L\to \mu e$ and $K\to \pi \mu e$ induced by the resulting vector leptoquarks. In this paper, we show that these constraints can be avoided once additional vector-like fermions are introduced and thus a breaking at the TeV scale is possible. We consider the flavor phenomenology of this model in the context of the intriguing hints for new physics in semileptonic $B$ decays. The necessary violation of lepton flavor universality is induced by mixing SM and vector-like fermions. Concerning $R(D)$ and $R(D^{\ast })$ we find that sizable effects are possible while respecting the bounds from other flavor observables but predicting a large enhancement of $B_s\to {\tau }^{+}{\tau }^{-}$. Furthermore, also in $b\to s{\ell }^{+}{\ell }^{-}$ transitions the observed deviations from the SM predictions (including $R(K)$ and $R(K^{\ast })$) can be explained with natural values for the free parameters of the model without any fine-tuning, predicting sizable decay rates for $b\to s\tau \mu$. Finally, the anomaly in anomalous magnetic moment of the muon can be accounted for by a loop-contribution involving the vector leptoquark and vector-like leptons.

   hep-phhep-exPRD(2018)·298 citations
10. 10*

    Heavy quark-philic scalar dark matter with a vector-like fermion portal

    Seungwon Baek🇰🇷 · Pyungwon Ko🇰🇷 · Peiwen Wu🇰🇷

    In this work we consider a real scalar dark matter $S$ interacting only with $SU(2{)}_L$ singlet Up-type quarks $U_i=u_R,c_R,t_R$ via a vector-like fermion $\psi$ which has the same quantum number as $U_i$. The DM-nucleon scattering can proceed through both $h$-mediated Higgs portal (HP) and $\psi$-mediated vector-like portal (VLP), in which HP can receive sizable radiative corrections through the new fermions. We first study the separate constraints on the new Yukawa couplings $y_i$ and find that the constraints of XENON1T results are strong on $y_1$ from VLP scattering and on $y_3$ from its radiative contributions to HP scattering. Since both DM-light quark interactions and HP have been well studied in the existing literature, we move forward to focus on DM-heavy quark interactions. Since there is no valence $c,t$ quark inside nucleons at ${\mu }_{\mathrm{had}}\sim 1$ GeV, $y_2,y_3$ interactions are manifested in DM-gluon scattering at loop level. We find that renormalization group equation (RGE) and heavy quark threshold effects are important if one calculates the DM-nucleon scattering rate ${\sigma }_p^{\mathrm{SI}}$ at ${\mu }_{\mathrm{had}}\sim 1\mathrm{GeV}$ while constructing the effective theory at ${\mu }_{\mathrm{EFT}}\sim m_Z$. For the benchmarks $y_3=0.5,y_2=0.5,1,3$, combined results from ${\Omega }_{\mathrm{DM}}{h}^2\simeq 0.12$, XENON1T, Fermi-LAT, 13 TeV LHC data have almost excluded $m_S<m_t/2$ when only DM-$\{c,t\}$ interactions are considered. FCNC of top quark can be generated at both tree level $t\to {\psi }^{(\ast )}S\to cSS$ and loop level $t\to c+\gamma /g/Z$, of which the branching fractions are typically below $10^{-9}$ after passing the other constraints, which are still safe from the current top quark width measurements.

    hep-phJCAP(2018)·27 citations
11. 11*

    An optimal scheme for top quark mass measurement near $t\bar{t}$ threshold at future $e^{+}{e}^{-}$ colliders

    Wei-Guo Chen🇨🇳 · Xia Wan🇨🇳 · You-Kai Wang🇨🇳

    A simulation of top quark mass measurement scheme near the $t\bar{t}$ production threshold in future $e^{+}{e}^{-}$ colliders, e.g. the Circular Electron Positron Collider(CEPC), is performed. ${\chi }^2$ fitting method is adopted to determine the number of energy points to be taken and their locations. Our result shows that the optimal energy point is located near the largest slope of the cross section to beam energy and the most efficient scheme is to concentrate all luminosity on this single energy point in one parameter top mass fitting case. This suggests that the so called data driven method can be a best choice for the future real experimental measurement. Conveniently, the top mass statistical uncertainty can also be calculated directly by the error matrix even without any sampling and fitting. Agreement of the above two optimization methods has been checked. Our conclusion is that by taking 50~$f{b}^{-1}$ total effective integrated luminosity data, the statistical uncertainty of the top potential subtracted mass can be suppressed to about 7~MeV and the total uncertainty is about 30~MeV. This precision will help to identify the stability of the electroweak vacuum at the Planck scale.

    hep-phhep-exCPC(2018)·0 citations
12. 12*

    Spin-$0^{\pm }$ portal induced Dark Matter

    Sukanta Dutta🇮🇳 · Ashok Goyal🇮🇳 · Lalit Kumar Saini🇮🇳

    Standard model (SM) spin-zero singlets are constrained through their di-Bosonic decay channels via an effective coupling induced by a vector-like quark (VLQ) loop at the LHC for $\sqrt{s}$ = 13 TeV. These spin-zero resonances are then considered as portals for scalar, vector or fermionic dark matter particle interactions with SM gauge bosons. We find that the model is validated with respect to the observations from LHC data and from cosmology, indirect and direct detection experiments for an appreciable range of scalar, vector and fermionic DM masses greater than 300 GeV and VLQ masses $\ge$ 400 GeV, corresponding to the three choice of portal masses 270 GeV, 500 GeV and 750 GeV respectively.

    hep-phJHEP(2018)·6 citations
13. 13*

    BSM Landscape

    Hyung Do Kim🇰🇷

    BSM landscape of motivated and unmotivated theories is overviewed with an emphasis on new developments guided by naturalness principle.

    hep-ph0 citations
14. 14*

    Charmed Baryon Weak Decays with SU(3) Flavor Symmetry

    C.Q. Geng🇨🇳 · Y.K. Hsiao🇨🇳 · Chia-Wei Liu🇹🇼 · Tien-Hsueh Tsai🇹🇼

    We study the semileptonic and non-leptonic charmed baryon decays with $SU(3)$ flavor symmetry, where the charmed baryons can be ${\mathbf{B}}_c=({\Xi }_c^0,{\Xi }_c^{+},{\Lambda }_c^{+})$, ${\mathbf{B}}_c^{\prime }=({\Sigma }_c^{(++,+,0)},{\Xi }_c^{\prime (+,0)},{\Omega }_c^0)$, ${\mathbf{B}}_{cc}=({\Xi }_{cc}^{++},{\Xi }_{cc}^{+},{\Omega }_{cc}^{+})$, or ${\mathbf{B}}_{ccc}={\Omega }_{ccc}^{++}$. With ${\mathbf{B}}_n^{(\prime )}$ denoted as the baryon octet (decuplet), we find that the ${\mathbf{B}}_c\to {\mathbf{B}}_n^{\prime }{\ell }^{+}{\nu }_{\ell }$ decays are forbidden, while the ${\Omega }_c^0\to {\Omega }^{-}{\ell }^{+}{\nu }_{\ell }$, ${\Omega }_{cc}^{+}\to {\Omega }_c^0{\ell }^{+}{\nu }_{\ell }$, and ${\Omega }_{ccc}^{++}\to {\Omega }_{cc}^{+}{\ell }^{+}{\nu }_{\ell }$ decays are the only existing Cabibbo-allowed modes for ${\mathbf{B}}_c^{\prime }\to {\mathbf{B}}_n^{\prime }{\ell }^{+}{\nu }_{\ell }$, ${\mathbf{B}}_{cc}\to {\mathbf{B}}_c^{\prime }{\ell }^{+}{\nu }_{\ell }$, and ${\mathbf{B}}_{ccc}\to {\mathbf{B}}_{cc}^{(\prime )}{\ell }^{+}{\nu }_{\ell }$, respectively. We predict the rarely studied ${\mathbf{B}}_c\to {\mathbf{B}}_n^{(\prime )}M$ decays, such as $\mathcal{B}({\Xi }_c^0\to {\Lambda }^0{\bar{K}}^0,{\Xi }_c^{+}\to {\Xi }^0{\pi }^{+})=(8.3\pm 0.9,8.0\pm 4.1)\times 10^{-3}$ and $\mathcal{B}({\Lambda }_c^{+}\to {\Delta }^{++}{\pi }^{-},{\Xi }_c^0\to {\Omega }^{-}{K}^{+})=(5.5\pm 1.3,4.8\pm 0.5)\times 10^{-3}$. For the observation, the doubly and triply charmed baryon decays of ${\Omega }_{cc}^{+}\to {\Xi }_c^{+}{\bar{K}}^0$, ${\Xi }_{cc}^{++}\to ({\Xi }_c^{+}{\pi }^{+}$, ${\Sigma }_c^{++}{\bar{K}}^0)$, and ${\Omega }_{ccc}^{++}\to ({\Xi }_{cc}^{++}{\bar{K}}^0,{\Omega }_{cc}^{+}{\pi }^{+},{\Xi }_c^{+}{D}^{+})$ are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.

    hep-phhep-exJHEP(2017)·93 citations
15. 15*

    Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

    Yasuhiro Yamaguchi🇯🇵 · Alessandro Giachino🇮🇹 · Atsushi Hosaka🇯🇵 · Elena Santopinto🇮🇹 · Sachiko Takeuchi🇯🇵 · Makoto Takizawa🇯🇵

    In this paper, we investigate the hidden-charm pentaquarks as ${\bar{D}}^{(\ast )}{\Lambda }_{\mathrm{c}}$ and ${\bar{D}}^{(\ast )}{\Sigma }_{\mathrm{c}}^{(\ast )}$ molecules coupled to the five-quark states. Furthermore, we extend our calculations to the hidden-bottom sector. The coupling to the five-quark states is treated as the short range potential, where the relative strength for the meson-baryon channels is determined by the structure of the five-quark states. We found that resonant and/or bound states appear in both the charm and bottom sectors. The five-quark state potential turned out to be attractive and, for this reason, it plays an important role to produce these states. In the charm sector, we need the five-quark potential in addition to the pion exchange potential in producing bound and resonant states, whereas, in the bottom sector, the pion exchange interaction is strong enough to produce states. Thus, from this investigation, it emerges that the hidden-bottom pentaquarks are more likely to form than their hidden-charm counterparts; for this reason, we suggest that the experimentalists should look for states in the bottom sector.

    hep-phnucl-thPRD(2017)·81 citations
16. 16*

    Searches for Sterile Neutrinos at Future Electron-Proton Colliders

    Stefan Antusch🇨🇭 · Oliver Fischer🇨🇭

    Sterile neutrinos are an attractive extension of the Standard Model of elementary particles towards including a mechanism for generating the observed light neutrino masses. We discuss that when an approximate protective "lepton number"-like symmetry is present, the sterile neutrinos can have masses around the electroweak scale and potentially large neutrino Yukawa couplings, which makes them well testable at planned future particle colliders. We systematically discuss the production and decay channels for sterile neutrinos at electron-proton colliders and give a complete list of the leading order signatures for sterile neutrino searches. We highlight several novel search channels and present a first look at the possible sensitivities for the active-sterile mixing parameters and the heavy neutrino masses. We also compare the performance of electron-proton colliders with the ones of proton-proton and electron-positron colliders, and discuss the complementarity of the different collider types.

    hep-phPoS(2018)·2 citations
17. 17*

    Wigner Distributions For Gluons

    Jai More🇮🇳 · Asmita Mukherjee🇮🇳 · Sreeraj Nair🇮🇳

    We investigate the gluon Wigner distributions for unpolarized, longitudinally polarized and transversely polarized target state. Instead of a nucleon, we take the target state to be a quark dressed with a gluon at one loop and investigate the gluon Wigner distributions at leading twist. Better numerical convergence is obtained compared to an earlier study, that removes the regulator dependence of the results. We present a first calculation of the Wigner distribution for the transversely polarized target and linearly polarized gluon. We study the spin densities in momentum and impact parameter space. We also investigate the quark and gluon helicity and orbital angular momentum distributions at small-$x$.

    hep-phEPJC(2018)·40 citations
18. 18*

    Entropy production and isotropization in Yang-Mills theory with use of quantum distribution function

    Hidekazu Tsukiji🇯🇵 · Teiji Kunihiro🇯🇵 · Akira Ohnishi🇯🇵 · Toru T. Takahashi🇯🇵

    We investigate thermalization process in relativistic heavy ion collisions in terms of the Husimi-Wehrl (HW) entropy defined with the Husimi function, a quantum distribution function in a phase space. We calculate the semiclassical time evolution of the HW entropy in Yang-Mills field theory with the phenomenological initial field configuration known as the McLerran-Venugopalan model in a non-expanding geometry, which has instabilty triggered by initial field fluctuations. HW-entropy production implies the thermalization of the system and it reflects the underlying dynamics such as chaoticity and instability. By comparing the production rate with the Kolmogorov-Sinaï rate, we find that the HW entropy production rate is significantly larger than that expected from chaoticity. We also show that the HW entropy is finally saturated when the system reaches a quasi-stationary state. The saturation time of the HW entropy is comparable with that of pressure isotropization, which is around $1$ fm/c in the present calculation in the non-expanding geometry.

    hep-phcond-mat.stat-mechhep-thnucl-th+1PTEP(2018)·13 citations
19. 19*

    Determining Form Factors and Wilson Coefficients using $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ data

    Bharti Kindra🇮🇳 · Namit Mahajan🇮🇳

    A method to extract Wilson coefficients for semi-leptonic $b\to s$ transition and form factors for the hadronic process $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ is suggested. The method is based on data of angular distribution of the process $B\to K^{\ast }(\to K\pi ){\mu }^{+}{\mu }^{-}$ with the optimized observables plotted as functions of dilepton invariant mass squared. We have constructed plots of the observables using present knowledge of Wilson coefficients and form factors. Assuming these plots to be experimental data, we have discussed and used the strategy to determine the form factors and Wilson coefficients. The method is novel as this provides a form-factor-independent determination of Wilson coefficients and also provides a reliable data driven method to extract information about form factors.

    hep-phhep-ex0 citations
20. 20*

    Exclusive pion-induced Drell-Yan process at J-PARC for accessing the nucleon GPDs and soft nonfactorizable mechanism

    Kazuhiro Tanaka (Juntendo Univ.)🇯🇵

    Generalized parton distributions (GPDs) encoding multidimensional information of hadron partonic structure appear as the building blocks in a factorized description of hard exclusive reactions. The nucleon GPDs have been accessed by deeply virtual Compton scattering and deeply virtual meson production with lepton beam. A complementary probe with hadron beam is shown to be the exclusive pion-induced Drell-Yan process, ${\pi }^{-}p\to {\mu }^{+}{\mu }^{-}n$, as demonstrated by recent theoretical advances on describing this process in terms of QCD factorization as the partonic subprocess convoluted with the nucleon GPDs and the pion distribution amplitudes, and by the feasibility study for its measurement via a spectrometer at the High Momentum Beamline being constructed at J-PARC in Japan. We also discuss the possible soft partonic mechanisms beyond the QCD factorization framework, and present an estimate of the soft mechanisms at J-PARC kinematics, making use of dispersion relations and quark-hadron duality. Realization of the measurement of the exclusive pion-induced Drell-Yan process at J-PARC will provide a new test of QCD descriptions of a novel class of hard exclusive reactions, and also offer the possibility of experimentally accessing nucleon GPDs at large timelike virtuality.

    hep-phhep-exnucl-exnucl-thPoS(2018)·2 citations
21. 21*

    Unified Scenario for Composite Right-Handed Neutrinos and Dark Matter

    Hooman Davoudiasl🇺🇸 · Pier Paolo Giardino🇺🇸 · Ethan T. Neil🇺🇸 · Enrico Rinaldi🇺🇸

    We entertain the possibility that neutrino masses and dark matter (DM) originate from a common composite dark sector. A minimal effective theory can be constructed based on a dark $SU(3{)}_D$ interaction with three flavors of massless dark quarks; electroweak symmetry breaking gives masses to the dark quarks. By assigning a ${\mathbb{Z}}_2$ charge to one flavor, a stable "dark kaon" can provide a good thermal relic DM candidate. We find that "dark neutrons" may be identified as right handed Dirac neutrinos. Some level of "neutron-anti-neutron" oscillation in the dark sector can then result in non-zero Majorana masses for light Standard Model neutrinos. A simple ultraviolet completion is presented, involving additional heavy $SU(3{)}_D$-charged particles with electroweak and lepton Yukawa couplings. At our benchmark point, there are "dark pions" that are much lighter than the Higgs and we expect spectacular collider signals arising from the UV framework. This includes the decay of the Higgs boson to $\tau \tau \ell {\ell }^{\prime }$, where $\ell$(${\ell }^{\prime }$) can be any lepton, with displaced vertices. We discuss the observational signatures of this UV framework in dark matter searches and primordial gravitational wave experiments; the latter signature is potentially correlated with the $H\to \tau \tau \ell {\ell }^{\prime }$ decay.

    hep-phhep-exPRD(2017)·21 citations
22. 22*

    A generic anti-QCD jet tagger

    J. A. Aguilar-Saavedra🇪🇸 · Jack H. Collins🇺🇸 · Rashmish K. Mishra🇮🇹

    New particles beyond the Standard Model might be produced with a very high boost, for instance if they result from the decay of a heavier particle. If the former decay hadronically, then their signature is a single massive fat jet which is difficult to separate from QCD backgrounds. Jet substructure and machine learning techniques allow for the discrimination of many specific boosted objects from QCD, but the scope of possibilities is very large, and a suite of dedicated taggers may not be able to cover every possibility - in addition to making experimental searches cumbersome. In this paper we describe a generic model-independent tagger that is able to discriminate a wide variety of hadronic boosted objects from QCD jets using N-subjettiness variables, with a significance improvement varying between 2 and 8. This is in addition to any improvement that might come from a cut on jet mass. Such a tagger can be used in model-independent searches for new physics yielding fat jets. We also show how such a tagger can be applied to signatures over a wide range of jet masses without sculpting the background distributions, allowing to search for new physics as bumps on jet mass distributions.

    hep-phhep-exJHEP(2017)·119 citations
23. 23*

    QCD axions and axionlike particles in a two-inflation scenario

    Sebastian Hoof🇬🇧 · Joerg Jaeckel🇩🇪

    We investigate the phenomenology of QCD axions and axionlike particles in a scenario with two eras of inflation. In particular, we describe the possible solutions for the QCD axion field equation after the second inflation and reheating. We calculate the dilution numerically for QCD axions and give an analytic approximation for axionlike particles. While it has been realised before that such a scenario can dilute the axion energy density and open up the parameter space for the axion decay constant $f_A$, we find that even a small increase in the relative QCD axion energy density is possible.

    hep-phastro-ph.COPRD(2017)·15 citations
24. 24*

    High-Energy Limit of QCD beyond Sudakov Approximation

    Tao Liu🇨🇦 · Alexander A. Penin🇨🇦

    We study the high-energy limit of the scattering amplitudes suppressed by the leading power of the quark mass in perturbative quantum chromodynamics. We prove the factorization and perform all-order resummation of the double-logarithmic radiative corrections which determine the asymptotic behavior of the amplitudes. In contrast to the Sudakov logarithms, the mass-suppressed double-logarithmic corrections are induced by soft quark exchange. The structure of the corrections and the asymptotic behavior of the amplitudes in this case crucially depend on the color flow in a given process and are determined by the eikonal color charge nonconservation. We present explicit results for the Higgs boson production in gluon fusion mediated by a light-quark loop and for the leading power-suppressed contributions to the quark form factors, which reveal "magical" universality. Nontrivial relations between the asymptotic behavior of different amplitudes and the amplitudes in different gauge theories are found.

    hep-phhep-thPRL(2017)·74 citations
25. 25*

    GPDs from charged current meson production in $ep$ experiments

    Marat Siddikov🇨🇱 · Ivan Schmidt🇨🇱

    We suggest that generalized parton distributions can be probed in charged current meson production process, $ep\to {\nu }_e{\pi }^{-}p$. In contrast to pion photoproduction, this process is sensitive to the unpolarized GPDs $H,E$, and for this reason has a very small contamination by higher twist and Bethe-Heitler type contributions. Since all produced hadrons are charged, we expect that the kinematics of this process could be easily reconstructed. We estimated the cross-sections in the kinematics of upgraded 12 GeV Jefferson Laboratory experiments and found that thanks to large luminosity the process can be measured with reasonable statistics.

    hep-phhep-exPRD(2017)·4 citations
26. 26*

    A Light Dilatonic Higgs and a Dilatonic Inflaton in the Georgi-Glashow SU(5) Model

    Hassan Saadi🇨🇦

    In this paper, two dilatonic fields that capture two conformal symmetries in the Georgi-Glashow SU(5) model are introduced. Then, one of the fields is associated with the Higgs, and the other one with inflation. By using the Higgs portal, the mass of the dilatonic Higgs can be tuned by the coupling constant between the two dilatonic fields.

    hep-ph2 citations
27. 27*

    Radiation from Atoms Falling into a Black Hole

    Marlan O. Scully🇺🇸 · Stephen Fulling🇺🇸 · David Lee🇺🇸 · Don N. Page🇨🇦 · Wolfgang Schleich🇺🇸 · Anatoly Svidzinsky🇺🇸

    We show that atoms falling from outside through a cavity into a black hole (BH) emit acceleration radiation which to a distant observer looks much like Hawking BH radiation. In particular, we find the entropy of the acceleration radiation via a simple laser-like analysis. We call this entropy Horizon Brightened Acceleration Radiation (HBAR) entropy to distinguish it from the BH entropy of Bekenstein and Hawking.

    ↳ quant-phgr-qchep-phhep-thProc.Nat.Acad.Sci.(2018)·95 citations
28. 28*

    Performance of Monte Carlo Event Generators for the Production of Boson and Multi-Boson States ATLAS Analysis

    Francesco Giuli🇬🇧

    The Monte Carlo (MC) setups used by ATLAS to model boson$+\mathrm{jets}$ and multi-boson processes at $\sqrt{s}$ = 13 TeV in proton-proton collisions are described. Comparisons between data and several event generators are provided for key kinematic distributions. Issues associated with the evaluation of systematic uncertainties are also discussed. This proceeding is a summary of the results collected in two recent ATLAS PUB notes published for the MC workshop jointly-organised by the the ATLAS and CMS Collaborations and held at CERN in May 2017.

    ↳ hep-exhep-phPoS(2017)·1 citation
29. 29*

    Isotope shift, non-linearity of King plots and the search for new particles

    V. V. Flambaum🇦🇺 · A. J. Geddes🇦🇺 · A. V. Viatkina🇩🇪

    We derive a mean-field relativistic formula for the isotope shift of an electronic energy level for arbitrary angular momentum; we then use it to predict the spectra of superheavy metastable neutron-rich isotopes belonging to the hypothetical island of stability. Our results may be applied to the search for superheavy atoms in astrophysical spectra using the known values of the transition frequencies for the neutron deficient isotopes produced in the laboratory. An example of a relevant astrophysical system may be the spectra of the Przybylski's star where superheavy elements up to Z=99 have been possibly identified. In addition, it has been recently suggested to use the measurements of King plot non-linearity in a search for hypothetical new light bosons. On the other hand, one can find the non-linear corrections to the King-plot arising already in the Standard Model framework. We investigate contributions to the non-linearity arising from relativistic effects in the isotope field-shift, the nuclear polarizability and many-body effects. It is found that the nuclear polarizability contribution can lead to the significant deviation of the King plot from linearity. Therefore, the measurements of the non-linearity of King plots may be applied to obtain the nuclear polarizability change between individual isotopes. We then proceed with providing a rough analytical estimate of the non-linearity arising solely from the effect of a hypothetical scalar boson. Our predictions give theoretical limitations on the sensitivity of the search for new interactions and should help to identify the most suitable atoms for corresponding experiments.

    ↳ physics.atom-phastro-ph.SRhep-phnucl-thPRA(2018)·99 citations
30. 30*

    Most Strange Dibaryon from Lattice QCD

    Shinya Gongyo🇯🇵 · Kenji Sasaki🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Yoichi Ikeda🇯🇵 · Takashi Inoue🇯🇵 · Takumi Iritani🇯🇵 · Noriyoshi Ishii🇯🇵 · Takaya Miyamoto🇯🇵 · Hidekatsu Nemura🇯🇵

    The $\Omega \Omega$ system in the ${}^1{S}_0$ channel (the most strange dibaryon) is studied on the basis of the (2+1)-flavor lattice QCD simulations with a large volume (8.1 fm)${}^3$ and nearly physical pion mass $m_{\pi }\simeq 146$ MeV at a lattice spacing $a\simeq 0.0846$ fm. We show that lattice QCD data analysis by the HAL QCD method leads to the scattering length $a_0=4.6(6){(}_{-0.5}^{+1.2})\mathrm{fm}$, the effective range $r_{\mathrm{eff}}=1.27(3){(}_{-0.03}^{+0.06})\mathrm{fm}$ and the binding energy $B_{\Omega \Omega }=1.6(6){(}_{-0.6}^{+0.7})\mathrm{MeV}$. These results indicate that the $\Omega \Omega$ system has an overall attraction and is located near the unitary regime. Such a system can be best searched experimentally by the pair-momentum correlation in relativistic heavy-ion collisions.

    ↳ hep-lathep-exhep-phnucl-ex+1PRL(2018)·153 citations
31. 31*

    Current status of direct dark matter detection experiments

    Jianglai Liu🇨🇳 · Xun Chen🇨🇳 · Xiangdong Ji🇨🇳

    Much like ordinary matter, dark matter might consist of elementary particles, and weakly interacting massive particles are one of the prime suspects. During the past decade, the sensitivity of experiments trying to directly detect them has improved by three to four orders of magnitude, but solid evidence for their existence is yet to come. We overview the recent progress in direct dark matter detection experiments and discuss future directions.

    ↳ astro-ph.COhep-exhep-phphysics.ins-detNat.Phys.(2017)·259 citations
32. 32*

    Spontaneous $CP$ breaking in QCD and the axion potential: an effective Lagrangian approach

    Paolo Di Vecchia🇩🇰 · Giancarlo Rossi🇮🇹 · Gabriele Veneziano🇫🇷 · Shimon Yankielowicz🇮🇱

    Using the well-known low-energy effective Lagrangian of QCD --valid for small (non-vanishing) quark masses and a large number of colors-- we study in detail the regions of parameter space where $CP$ is spontaneously broken/unbroken for a vacuum angle $\theta =\pi$. In the $CP$-broken region there are first order phase transitions as one crosses $\theta =\pi$, while on the (hyper)surface separating the two regions, there are second order phase transitions signaled by the vanishing of the mass of a pseudo Nambu-Goldstone boson and by a divergent QCD topological susceptibility. The second order point sits at the end of a first order line associated with the $CP$ spontaneous breaking, in the appropriate complex parameter plane. When the effective Lagrangian is extended by the inclusion of an axion these features of QCD imply that standard calculations of the axion potential have to be revised when the QCD parameters fall in the above mentioned $CP$-broken region, in spite of the fact that the axion solves the strong-$CP$ problem. These latter results could be of interest for axionic dark matter calculations if the topological susceptibility of pure Yang-Mills theory falls off sufficiently fast when temperature is increased towards the QCD deconfining transition.

    ↳ hep-thgr-qchep-phJHEP(2017)·53 citations
33. 33*

    Collision Energy Dependence of Moments of Net-Kaon Multiplicity Distributions at RHIC

    STAR Collaboration: L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · N. N. Ajitanand · I. Alekseev · D. M. Anderson · R. Aoyama · A. Aparin · D. Arkhipkin and 339 other authors

    Fluctuations of conserved quantities such as baryon number, charge, and strangeness are sensitive to the correlation length of the hot and dense matter created in relativistic heavy-ion collisions and can be used to search for the QCD critical point. We report the first measurements of the moments of net-kaon multiplicity distributions in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV. The collision centrality and energy dependence of the mean ($M$), variance (${\sigma }^2$), skewness ($S$), and kurtosis ($\kappa$) for net-kaon multiplicity distributions as well as the ratio ${\sigma }^2/M$ and the products $S\sigma$ and $\kappa {\sigma }^2$ are presented. Comparisons are made with Poisson and negative binomial baseline calculations as well as with UrQMD, a transport model (UrQMD) that does not include effects from the QCD critical point. Within current uncertainties, the net-kaon cumulant ratios appear to be monotonic as a function of collision energy.

    ↳ nucl-exhep-exhep-phnucl-thPLB(2018)·175 citations
34. 34*

    Standard sirens and dark sector with Gaussian process

    Rong-Gen Cai🇨🇳 · Tao Yang🇨🇳

    The gravitational waves from compact binary systems are viewed as a standard siren to probe the evolution of the universe. This paper summarizes the potential and ability to use the gravitational waves to constrain the cosmological parameters and the dark sector interaction in the Gaussian process methodology. After briefly introducing the method to reconstruct the dark sector interaction by the Gaussian process, the concept of standard sirens and the analysis of reconstructing the dark sector interaction with LISA are outlined. Furthermore, we estimate the constraint ability of the gravitational waves on cosmological parameters with ET. The numerical methods we use are Gaussian process and the Markov-Chain Monte-Carlo. Finally, we also forecast the improvements of the abilities to constrain the cosmological parameters with ET and LISA combined with the \it Planck.

    ↳ astro-ph.COgr-qchep-phEPJ Web Conf.(2018)·17 citations
35. 35*

    Higher order net-proton number cumulants dependence on the centrality definition and other spurious effects

    S. Sombun🇹🇭 · J. Steinheimer🇩🇪 · C. Herold🇹🇭 · A. Limphirat🇹🇭 · Y. Yan🇹🇭 · M. Bleicher🇩🇪

    We study the dependence of the normalized moments of the net-proton multiplicity distributions on the definition of centrality in relativistic nuclear collisions at a beam energy of $\sqrt{s_{\mathrm{NN}}}=7.7$ GeV. Using the UrQMD model as event generator we find that the centrality definition has a large effect on the extracted cumulant ratios. Furthermore we find that the finite efficiency for the determination of the centrality introduces an additional systematic uncertainty. Finally, we quantitatively investigate the effects of event-pile up and other possible spurious effects which may change the measured proton number. We find that pile-up alone is not sufficient to describe the data and show that a random double counting of events, adding significantly to the measured proton number, affects mainly the higher order cumulants in most central collisions.

    ↳ nucl-thhep-phJ.Phys.G(2018)·19 citations
36. 36*

    Quantum coherence of cosmological perturbations

    Massimo Giovannini🇨🇭

    The degrees of quantum coherence of cosmological perturbations of different spins are computed in the large-scale limit and compared with the standard results holding for a single mode of the electromagnetic field in an optical cavity. The degree second-order coherence of curvature inhomogeneities (and, more generally, of the scalar modes of the geometry) reproduces faithfully the optical limit. For the vector and tensor fluctuations the numerical values of the normalized degrees of second-order coherence in the zero-time delay limit are always larger than unity (which is the Poisson benchmark value) but differ from the corresponding expressions obtainable in the framework of the single-mode approximation. General lessons are drawn on the quantum coherence of large-scale cosmological fluctuations.

    ↳ gr-qcastro-ph.COhep-phhep-thMod.Phys.Lett.A(2017)·13 citations
37. 37*

    Search for supersymmetric partners of third generation quarks in leptonic channels with the ATLAS detector

    Keisuke Yoshihara🇺🇸

    Two of the most important parameters in supersymmetry are the masses of the stop and sbottom, the supersymmetric partners of the third generation quarks. A stop mass lighter than 1 TeV is favored theoretically, however, conventional searches based on the simplified models have not produced experimental evidence for a light stop. It is possible that the light stop evades our searches due to a compressed sparticle mass spectrum. Therefore, the searches are extended to cover a broader range of signal scenarios with different mass splittings between the stop, neutralino(s), and chargino(s). The searches are then interpreted in the context of both simplified models and pMSSM models. Searches are also performed for various R-parity violating stop (sbottom) models. Recent ATLAS results from searches for direct stop (sbottom) pair production are presented in final states with jets, missing transverse-momentum, and leptons. The analyses are based on 36 fb${}^{-1}$ of $\sqrt{s}$=13 TeV proton-proton collision data recorded with ATLAS detector at the LHC in 2015 and 2016.

    ↳ hep-exhep-ph2 citations
38. 38*

    Atmospheric muons charge ratio analysis at the INO-ICAL detector

    Jaydip Singh🇮🇳 · Jyotsna Singh🇮🇳

    The proposed Iron Calorimeter (ICAL) detector at Indian Neutrino Observatory(INO) will be a large (50 kt) magnetized detector located 1270 m underground at Bodi West Hills in Tamilnadu. ICAL is capable of identifying the charge of the particles. In this paper its potential for the measurement of the muon charge ratio is explored by means of a detailed simulation-based study, first using the CORSIKA code and then comparing it with an analytical model (the "pika" model). The estimated muon charge ratio is in agreement with the existing experimental observations, its measure can be extended by INO-ICAL up to 10 TeV and up to 60 degrees.

    ↳ physics.ins-dethep-phAdv.High Energy Phys.(2019)·2 citations
39. 39*

    No evidence for dynamical dark energy in two models

    Deng Wang🇨🇳 · Xin-He Meng🇨🇳

    To investigate whether the dark energy evolves over time, we propose two null tests and constrain them using the data combination of cosmic microwave background radiation, baryonic acoustic oscillations, Type Ia supernovae, Planck-2015 lensing and cosmic chronometers. We find that, for these two models, there is no evidence of the dynamical dark energy at the $1.2\sigma$ confidence level. Interestingly, both models could slightly alleviate (i) the current Hubble constant ($H_0$) tension between the global fitting derivation by the Planck collaboration and the local observation by Riess {\it et al.}; (ii) the root-mean-square density fluctuations (${\sigma }_8$) tension between the Planck-2015 data and several low-redshift large scale structure probes.

    ↳ astro-ph.COgr-qchep-phPRD(2017)·17 citations
40. 40*

    Double Gamow-Teller transitions and its relation to neutrinoless $\beta \beta$ decay

    Noritaka Shimizu🇯🇵 · Javier Menéndez🇯🇵 · Kentaro Yako🇯🇵

    We study the double Gamow-Teller (DGT) strength distribution of ${}^{48}$Ca with state-of-the-art large-scale nuclear shell model calculations. Our analysis shows that the centroid energy of the DGT giant resonance depends mostly on the isovector pairing interaction, while the resonance width is more sensitive to isoscalar pairing. Pairing correlations are also key in neutrinoless $\beta \beta$ ($0\nu \beta \beta$) decay. We find a simple relation between the centroid energy and width of the ${}^{48}$Ca DGT giant resonance and %the value of the $0\nu \beta \beta$ decay nuclear matrix element. More generally, we observe a very good linear correlation between the DGT transition to the ground state of the final nucleus and the $0\nu \beta \beta$ decay matrix element. The correlation, which originates on the dominant short-range character of both transitions, extends to heavier systems including several $\beta \beta$ emitters, and also holds in energy-density functional results. Our findings suggest that DGT experiments can be a very valuable tool to obtain information on the value of $0\nu \beta \beta$ decay nuclear matrix elements.

    ↳ nucl-thhep-exhep-phnucl-exPRL(2018)·103 citations
41. 41*

    Dark energy two decades after: Observables, probes, consistency tests

    Dragan Huterer🇺🇸 · Daniel L Shafer🇺🇸

    The discovery of the accelerating universe in the late 1990s was a watershed moment in modern cosmology, as it indicated the presence of a fundamentally new, dominant contribution to the energy budget of the universe. Evidence for dark energy, the new component that causes the acceleration, has since become extremely strong, owing to an impressive variety of increasingly precise measurements of the expansion history and the growth of structure in the universe. Still, one of the central challenges of modern cosmology is to shed light on the physical mechanism behind the accelerating universe. In this review, we briefly summarize the developments that led to the discovery of dark energy. Next, we discuss the parametric descriptions of dark energy and the cosmological tests that allow us to better understand its nature. We then review the cosmological probes of dark energy. For each probe, we briefly discuss the physics behind it and its prospects for measuring dark energy properties. We end with a summary of the current status of dark energy research.

    ↳ astro-ph.COastro-ph.GAgr-qchep-ph+1Rept.Prog.Phys.(2018)·365 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.