Tue·Dec 8, 2015Tuesday·December 8, 2015

1. 01*

   An analysis of the impact of LHC Run I proton-lead data on nuclear parton densities

   Néstor Armesto🇪🇸 · Hannu Paukkunen🇫🇮 · José Manuel Penín🇪🇸 · Carlos A. Salgado🇪🇸 · Pía Zurita🇪🇸

   We report on an analysis of the impact of available experimental data on hard processes in proton-lead collisions during Run I at the Large Hadron Collider on nuclear modifications of parton distribution functions. Our analysis is restricted to the EPS09 and DSSZ global fits. The measurements that we consider comprise production of massive gauge bosons, jets, charged hadrons and pions. This is the first time a study of nuclear PDFs includes this number of different observables. The goal of the paper is twofold: i) checking the description of the data by nPDFs, as well as the relevance of these nuclear effects, in a quantitative manner; ii) testing the constraining power of these data in eventual global fits, for which we use the Bayesian reweighting technique. We find an overall good, even too good, description of the data, indicating that more constraining power would require a better control over the systematic uncertainties and/or the proper proton-proton reference from LHC Run II. Some of the observables, however, show sizable tension with specific choices of proton and nuclear PDFs. We also comment on the corresponding improvements on the theoretical treatment.

   hep-phhep-exnucl-exnucl-thEPJC(2016)·48 citations
2. 02*

   Generalized $\mu -\tau$ reflection symmetry and leptonic CP violation

   Peng Chen🇨🇳 · Gui-Jun Ding🇨🇳 · Felix Gonzalez-Canales🇪🇸 · J. W. F. Valle🇪🇸

   We propose a generalized $\mu -\tau$ reflection symmetry to constrain the lepton flavor mixing parameters. We obtain a new correlation between the atmospheric mixing angle ${\theta }_{23}$ and the "Dirac" CP violation phase ${\delta }_{\mathrm{CP}}$. Only in a specific limit our proposed CP transformation reduces to standard $\mu -\tau$ reflection, for which ${\theta }_{23}$ and ${\delta }_{CP}$ are both maximal. The "Majorana" phases are predicted to lie at their CP-conserving values with important implications for the neutrinoless double beta decay rates. We also study the phenomenological implications of our scheme for present and future neutrino oscillation experiments including T2K, NO$\nu$A and DUNE.

   hep-phhep-thPLB(2016)·76 citations
3. 03*

   Anomalies in $B$-decays and $U(2)$ flavour symmetry

   Riccardo Barbieri🇮🇹 · Gino Isidori🇨🇭 · Andrea Pattori🇨🇭 · Fabrizio Senia🇮🇹

   The collection of a few anomalies in semileptonic $B$-decays invites to speculate about the emergence of some strikingly new phenomena. Here we offer a possible interpretation of these anomalies in the context of a weakly broken $U(2{)}^5$ flavour symmetry and lepto-quark mediators.

   hep-phEPJC(2016)·361 citations
4. 04*

   CCharge-multiplicity dependence of single-particle transverse-rapidity ${\mathbf{y}}_{\mathbf{t}}$ and pseudorapidity $\eta$ densities and 2D angular correlations from 200 GeV $p$-$p$ collisions

   Thomas A. Trainor🇺🇸 · Duncan J. Prindle🇺🇸

   An established phenomenology and theoretical interpretation of $p$-$p$ collision data at lower collision energies should provide a reference for $p$-$p$ and other collision systems at higher energies, against which claims of novel physics may be tested. The description of $p$-$p$ collisions at the relativistic heavy ion collider (RHIC) has remained incomplete even as claims for collectivity and other novelties in data from smaller systems at the large hadron collider (LHC) have emerged recently. In this study we report the charge-multiplicity dependence of two-dimensional (2D) angular correlations and of single-particle (SP) densities on transverse rapidity $y_t$ and pseudorapidity $\eta$ from 200 GeV $p$-$p$ collisions. We define a comprehensive and self-consistent two-component (soft + hard) model (TCM) for hadron production and report a significant $p$-$p$ nonjet (NJ) quadrupole component as a third (angular-correlation) component. Our results have implications for $p$-$p$ centrality, the underlying event (UE), collectivity in small systems and the existence of flows in high-energy nuclear collisions.

   hep-phPRD(2016)·32 citations
5. 05*

   Study of 1D stranged-charm meson family using HQET

   Pallavi Gupta🇮🇳 · Alka Upadhyay🇮🇳

   Recently LHCb predicted spin 1 and spin 3 states D* s1(2860) and D* s3(2860) which are studied through their strong decays, and are assigned to fit the 13D1and 13D3 states in the charm spectroscopy. In this paper,using the heavy quark effective theory, we state that assigning D*s1(2860) as the mixing of 13D1 - 23S1 states, is rather a better justification to its observed experimental values than a pure state. We study its decay modes variation with hadronic coupling constant gxh and the mixing angle . We appoint spin 3 state D* s3(2860) as the missing 1D 3- JP state, and also study its decay channel behavior with coupling constant gyh. To appreciate the above results, we check the variation of decay modes for their spin partners states i.e. 1D2 and 1D'2 with their masses and strong coupling constant i.e. gxh and gyh. Our calculation using HQET approach give mixing angle between the 13D1 - 23S1 state for D* s1(2860) to lie in the range (-1.6 radians < theta < -1.2 radians). Our calculation for coupling constant values gives gxh to lie between value 0:17 < gxh < 0:20 and gyh to be 0.40. We expect from experiments to observe this mixing angle to verify our results.

   hep-phAdv.High Energy Phys.(2016)·0 citations
6. 06*

   Bayesian model comparison for one-dimensional azimuthal correlations in 200GeV AuAu collisions

   Hans C. Eggers🇿🇦 · Michiel B. de Kock🇿🇦 · Thomas A. Trainor🇺🇸

   In the context of data modeling and comparisons between different fit models, Bayesian analysis calls that model best which has the largest evidence, the prior-weighted integral over model parameters of the likelihood function. Evidence calculations automatically take into account both the usual chi-squared measure and an Occam factor which quantifies the price for adding extra parameters. Applying Bayesian analysis to projections onto azimuth of 2D angular correlations from 200 GeV AuAu collisions, we consider typical model choices including Fourier series and a Gaussian plus combinations of individual cosine components. We find that models including a Gaussian component are consistently preferred over pure Fourier-series parametrizations, sometimes strongly so. For 0-5% central collisions the Gaussian-plus-dipole model performs better than Fourier Series models or any other combination of Gaussian-plus-multipoles.

   hep-phEPJ Web Conf.(2016)·0 citations
7. 07*

   The Lifetime of Axion Stars

   Joshua Eby🇺🇸 · Peter Suranyi🇺🇸 · L.C.R. Wijewardhana🇺🇸

   We investigate the decay of condensates of scalars in a field theory defined by $V(\mathcal{A})=m{}^{2}f{}^2[1-\cos (\mathcal{A}/f)]$, where $m$ and $f$ are the mass and decay constant of the scalar field. An example of such a theory is that of the axion, in which case the condensates are called axion stars. The axion field, $\mathcal{A}$, is self adjoint. As a result the axion number is not an absolutely conserved quantity. Therefore, axion stars are not stable and have finite lifetimes. Bound axions, localized on the volume of the star, have a coordinate uncertainty $\Delta x\sim R\sim 1/(m_a\Delta )$, where $R$ is the radius of the star and $\Delta =\sqrt{1-E_0{}^2/m_a^2}$. Here $m_a$ and $E_0$ are the mass, and the ground state energy of the bound axion. Then the momentum distribution of axions has a width of $\Delta p\sim m_a\Delta$. At strong binding, $\Delta =\mathcal{O}(1)$, bound axions can easily transfer a sufficient amount of momentum to create and emit a free axion, leading to fast decay of the star with a transition rate $\Gamma \sim m_a$. However, when $\Delta \ll 1$, the momentum distribution is more restricted, and as shown in this paper, the transition rate for creating a free axion decreases as $\exp (-p\Delta x)\sim \exp (-{\Delta }^{-1})$. Then sufficiently large, weakly bound axion stars, produced after the big bang, survive until the present time. We plot the region of their stability, limited by decay through axion loss and by gravitational instability, as a function of the mass of the axion and the mass of the star.

   hep-phastro-ph.COhep-thMod.Phys.Lett.A(2016)·87 citations
8. 08*

   Double Higgs boson production and decay in Randall-Sundrum model at hadron colliders

   Zhang Wen-Juan🇨🇳 · Ma Wen-Gan🇨🇳 · Zhang Ren-You🇨🇳 · Li Xiao-Zhou🇨🇳 · Guo Lei🇨🇳 · Chen Chong🇨🇳

   We investigate the double Higgs production and decay at the $14\mathrm{TeV}$ LHC and $33\mathrm{TeV}$ HE-LHC in both the standard model and Randall-Sundrum (RS) model. In our calculation we consider reasonably only the contribution of the lightest two Kaluza-Klein (KK) gravitons. We present the integrated cross sections and some kinematic distributions in both models. Our results show that the RS effect in the vicinities of $M_{HH}\sim M_1$, $M_2$ (the masses of the lightest two KK gravitons) or in the central Higgs rapidity region is quite significant, and can be extracted from the heavy SM background by imposing proper kinematic cuts on final particles. We also study the dependence of the cross section on the RS model parameters, the first KK graviton mass $M_1$ and the effective coupling $c_0$, and find that the RS effect is reduced obviously with the increment of $M_1$ or decrement of $c_0$.

   hep-phPRD(2015)·17 citations
9. 09*

   Disentangling Shadowing from Coherent Energy Loss using the Drell-Yan Process

   François Arleo🇫🇷 · Stéphane Peigné🇫🇷

   We suggest the measurement of Drell-Yan (DY) lepton pairs in p-Pb collisions at the LHC (sqrt(s)=5.02 TeV) in order to disentangle the relative contributions of shadowing and coherent energy loss in quarkonium production off nuclei. The nuclear modification of low mass DY production is computed at NLO using various sets of nuclear parton densities. It is then observed that shadowing effects strongly cancel out in the J/psi over DY suppression ratio R_{pA}^{J/psi}(y) / R_{pA}^{DY}(y), unlike the effect of coherent energy loss. Such a measurement could be performed at forward rapidity by the ALICE and LHCb collaborations at the LHC.

   hep-phhep-exPRD(2017)·31 citations
10. 10*

    The axial charge of \Delta baryon in QCD

    U. Ozdem🇹🇷 · A. Kucukarslan🇹🇷 · A. Ozpineci🇹🇷

    The iso-vector axial-vector form factors of the \Delta-\Delta transition are calculated in the framework of the Light-cone QCD sum rules method. Also, axial charge of \Delta baryon is predicted.

    hep-ph0 citations
11. 11*

    Proton fragmentation functions considering finite-mass corrections

    S. M. Moosavi Nejad🇮🇷 · M. Soleymaninia🇮🇷 · A. Maktoubian🇮🇷

    We present new sets of proton fragmentation functions describing the production of protons from the gluon and each of the quarks, obtained by a global fit to all relevant data sets extracted from the single-inclusive electron-positron annihilation. Our analysis is in good agreement with $e^{+}{e}^{-}$ annihilation data. We also impose the finite-mass effects of proton in our calculations, a topic with a very little attention paid to in the literatures. Proton mass effects turn out to be appreciable for the gluon and light quark fragmentation functions, so the inclusion of finite-mass effects tends to improve the overall description of the data by reducing the minimized ${\chi }^2$ values, significantly. As an application, we also apply the extracted fragmentation functions to make our predictions for the scaled-energy distribution of protons inclusively produced in top quark decays at next-to-leading order, relying on the universality and scaling violations of fragmentation functions.

    hep-phEPJA(2016)·42 citations
12. 12*

    $\mathbf{p}$-$\mathbf{p}$ minimum-bias dijets and nonjet quadrupole in relation to conjectured collectivity (flows) in high-energy nuclear collisions

    Thomas A. Trainor🇺🇸

    Recent observations of ridge-like structure in $p$-$p$ and $p$-$A$ angular correlations at the RHIC and LHC have been interpreted to imply collective motion in smaller collision systems. It is argued that if correlation structures accepted as manifestations of flow in $A$-$A$ collisions appear in smaller systems collectivity (flow) must extend to the smaller systems. But the argument could be reversed to conclude that such structures appearing in $A$-$A$ collisions may not imply hydrodynamic flow. I present spectrum, correlation and fluctuation data from RHIC $p$-$p$ and Au-Au collisions and $p$-$p$, $p$-Pb and Pb-Pb results from the LHC described accurately by a two-component (soft+dijet) model of hadron production. I also present evidence for a significant $p$-$p$ nonjet (NJ) quadrupole ($v_2$) component with $n_{ch}$ systematics directly related to $A$-$A$ NJ quadrupole systematics. The combination suggests that soft, dijet and NJ quadrupole components are distinct phenomena in all cases, inconsistent with hadron production from a common bulk medium exhibiting collective motion (flow).

    hep-phEPJ Web Conf.(2016)·0 citations
13. 13*

    Precision study on $ZZ\gamma$ production including $Z$-boson leptonic decays at the ILC

    Zhang Yu🇨🇳 · Duan Peng-Fei🇨🇳 · Ma Wen-Gan🇨🇳 · Zhang Ren-You🇨🇳 · Chen Chong🇨🇳

    We report on the precision predictions for the $e^{+}{e}^{-}\to ZZ\gamma$ process including $Z$-boson leptonic decays at the ILC in the standard model (SM). The calculation includes the full next-to-leading (NLO) electroweak (EW) corrections and high order initial state radiation (h.o.ISR) contributions. We find that the NLO EW corrections heavily suppress the LO cross section, and the h.o.ISR effects are notable near the threshold while become small in high energy region. We present the LO and the NLO EW+h.o.ISR corrected distributions of the transverse momenta of final $Z$-boson and photon as well as the $Z$-pair invariant mass, and investigate the corresponding NLO EW and h.o.ISR relative corrections. We also study the leptonic decays of the final $Z$-boson pair by adopting the {\sc MadSpin} method where the spin correlation effect is involved. We conclude that both the h.o.ISR effects and the NLO EW corrections are important in exploring the $ZZ\gamma$ production at the ILC.

    hep-phEPJC(2016)·4 citations
14. 14*

    LHCb $P_c^{+}$ Resonances as Molecular States

    D. E. Kahana · S. H. Kahana🇺🇸

    Recent experiments at the LHCb detector have once again raised the possibility that quark bags may exist containing more than three quarks. Specifically the LHCb collaboration points to evidence for hadronic resonances decaying into J/$\psi$ and proton: the $P_c(4450{)}^{+}$ and $P_C(4380{)}^{+}$. Here we put forth a case that a reasonable description of these states is possible as molecular resonances of a $p$ and a J/$\psi$. Our model seems to accommodate the observed states and their measured widths, both the lower lying, broader, negative parity state and the higher lying, narrow positive parity state. If these resonances do indeed exist one might envision a rich spectroscopy of such pentaquark states waiting to be discovered, though this would deepen the mystery of their absence in earlier hadron spectroscopy. Perhaps the presence of the heavy charmed quarks, as well as the lighter u,d and s quarks, is the determining factor.

    hep-phnucl-th11 citations
15. 15*

    Strong decay patterns of the hidden-charm tetraquarks

    Li Ma🇨🇳 · Wei-Zhen Deng🇨🇳 · Xiao-Lin Chen🇨🇳 · Shi-Lin Zhu🇨🇳

    With the spin rearrangement, we have performed a comprehensive investigation of the decay patterns of the S-wave tetraquarks and P-wave tetraquarks where the P-wave excitation exists either between the diquark and anti-diquark pair or inside the diquark. Especially, we compare the decay patterns of $Y(4260)$ with different inner structures such as the conventional charmonium, the molecule, the P-wave tetraquark and the hybrid charmonium. We notice the $J/\psi \pi \pi$ mode is suppressed in the heavy quark symmetry limit if $Y(4260)$ is a molecular state. Moreover the hybrid charmonium and hidden-charm tetraquark have very similar decay patterns. Both of them decay into the $J/\psi \pi \pi$ and open charm modes easily. We also discuss the decay patterns of $X(3872)$, $Y(4360)$, and several charged states such as $Z_c(4020)$. The $h_c{\pi }^{\pm }$ decay mode disfavors the tetraquark assumption of $Z_c(4020)$.

    hep-phhep-exhep-latnucl-th9 citations
16. 16*

    On the Contributions to the ${\mathbf{U}}_{\mathbf{Y}}(1)$ Chern-Simons Term and the Evolution of Fermionic Asymmetries and Hypermagnetic Fields

    S. Rostam Zadeh🇮🇷 · S. S. Gousheh🇮🇷

    We study simultaneous evolution of electron, neutrino and quark asymmetries, and large scale hypermagnetic fields in the symmetric phase of the electroweak plasma in the temperature range $100$GeV$\le T\le 10$TeV, taking into account the chirality flip processes via inverse Higgs decays and fermion number violation due to Abelian anomalies. We present a derivation of the coefficient of the Chern-Simons term for the hypercharge gauge field, showing that the left-handed and right-handed components of each fermion species contribute with opposite sign. This is in contrast to the results presented in some of the previous works. The ${\text{U}}_{\text{Y}}(1)$ Chern-Simons term affects the resulting anomalous magnetohydrodynamic (AMHD) equations. We solve the resulting coupled evolution equations for the lepton and baryon asymmetries, as well as the hypermagnetic field to obtain their time evolution along with their values at the electroweak phase transition ($T_{EW}\sim 100$GeV) for a variety of critical ranges for their initial values at $T=10$TeV. We first investigate the results of this sign change, by directly comparing our results with those obtained in one of the previous works and find that matter asymmetry generation increases considerably in the presence of a strong hypermagnetic field. Furthermore, we find that a strong hypermagnetic field can generate matter asymmetry starting from absolutely zero asymmetry, while matter asymmetry can generate a hypermagnetic field provided the initial value of the latter is nonzero.

    hep-phhep-thPRD(2016)·21 citations
17. 17*

    Charged lepton flavor violation on target at GeV scale

    Wei Liao🇨🇳 · Xiao-Hong Wu🇨🇳

    We study the lepton flavor violating process, $e+T\to \tau +T^{\prime }$, at a few GeV. This process can be studied by experiments directing GeV scale electron or positron beams on internal or fixed targets. We study the effects of some low energy lepton flavor violating interactions on this process. We study the sensitivities of this process on these low energy lepton flavor violating interactions and compare them to the sensitivities of lepton flavor violating $\tau$ decay processes. Comparing with $\tau$ decay processes, this process provides another way to study the lepton flavor violating effects with $e-\tau$ conversion and it can be searched for in facilities with GeV scale electron or positron beams which are available in a number of laboratories in the world.

    hep-phhep-exPRD(2016)·6 citations
18. 18*

    A unified approach to hadron phenomenology at zero and finite temperatures in a hard-wall AdS/QCD model

    Zhiyuan Wang🇨🇳 · Bo-Qiang Ma🇨🇳

    We propose a unified approach to study meson, nucleon and $\Delta$-baryon properties at zero and finite temperatures in the context of hard-wall AdS/QCD model. We first combine some previous works dealing with mesons and baryons separately, and introduce a new parameter~$\xi$ so that the model could give a universal description of spectrum and couplings of both sectors in a self-consistent way. All observables calculated numerically show reasonable agreement with experimental data. We then study these observables at nonzero temperature by modifying the AdS space-time into AdS-Schwartzchild space-time. Numerically solving the model, we find an interesting temperature dependence of the spectrum and the couplings. We also make a prediction on the finite temperature decay width of some nucleon and $\Delta$ excited states.

    hep-phEPJA(2016)·6 citations
19. 19*

    A hidden-charm pentaquark state in ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ decay

    En Wang🇨🇳 · Hua-Xing Chen🇨🇳 · Li-Sheng Geng🇨🇳 · De-Min Li🇨🇳 · Eulogio Oset🇪🇸

    We study here the ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ reaction in analogy to the ${\Lambda }_b^0\to J/\psi p{K}^{-}$ one, and we note that in both decays there is a sharp structure (dip or peak) in the $J/\psi p$ mass distribution around $4450$ MeV, which is associated in the ${\Lambda }_b^0\to J/\psi p{K}^{-}$ experiment to an exotic pentaquark baryonic state, although in ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ it shows up with relatively low statistics. We analyze the ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ interaction along the same lines as the ${\Lambda }_b^0\to J/\psi p{K}^{-}$ one, with the main difference stemming from the reduced Cabibbo strength in the former and the consideration of the ${\pi }^{-}p$ final state interaction instead of the $K^{-}p$ one. We find that with a minimal input, introducing the ${\pi }^{-}p$ and $J/\psi p$ interaction in $S$-wave with realistic interactions, and the empirical $P$-wave and $D$-wave contributions, one can accomplish a qualitative description of the ${\pi }^{-}p$ and $J/\psi p$ mass distributions. More importantly, the peak structure followed by a dip of the experimental $J/\psi p$ mass distribution is reproduced with the same input as used to describe the data of ${\Lambda }_b^0\to J/\psi p{K}^{-}$ reaction. The repercussion for the triangular singularity mechanism, invoked in some works to explain the pentaquark peak, is discussed.

    hep-phPRD(2016)·66 citations
20. 20*

    Effective Field Theory and Electroweak Baryogenesis in the Singlet-Extended Standard Model

    P. H. Damgaard🇩🇰 · A. Haarr🇳🇴 · D. O'Connell🇬🇧 · A. Tranberg🇳🇴

    Electroweak baryogenesis is a simple and attractive candidate mechanism for generating the observed baryon asymmetry in the Universe. Its viability is sometimes investigated in terms of an effective field theory of the Standard Model involving higher dimension operators. We investigate the validity of such an effective field theory approach to the problem of identifying electroweak phase transitions strong enough for electroweak baryogenesis to be successful. We identify and discuss some pitfalls of this approach due to the modest hierarchy between mass scales of heavy degrees or freedom and the Higgs, and the possibility of dimensionful couplings violating the decoupling between light and heavy degrees of freedom.

    hep-phJHEP(2016)·80 citations
21. 21*

    Study of Majorana Fermionic Dark Matter

    Chun-Khiang Chua🇹🇼 · Gwo-Guang Wong🇹🇼

    We construct a generic model of Majorana fermionic dark matter (DM). Starting with two Weyl spinor multiplets ${\eta }_{1,2}\sim (I,\mp Y)$ coupled to the Standard Model (SM) Higgs, six additional Weyl spinor multiplets with $(I\pm 1/2,\pm (Y\pm 1/2))$ are needed in general. It has 13 parameters in total, five mass parameters and eight Yukawa couplings. The DM sector of the minimal supersymmetric standard model (MSSM) is a special case of the model with $(I,Y)=(1/2,1/2)$. Therefore, this model can be viewed as an extension of the neutralino DM sector. We consider three typical cases: the neutralino-like, the reduced and the extended cases. For each case, we survey the DM mass $m_{\chi }$ in the range of $(1,2500)$ GeV by random sampling from the model parameter space and study the constraints from the observed DM relic density, the direct search of LUX, XENON100 and PICO experiments, and the indirect search of Fermi-LAT data. We investigate the interplay of these constraints and the differences among these cases. It is found that the direct detection of spin-independent DM scattering off nuclei and the indirect detection of DM annihilation to $W^{+}{W}^{-}$ channel are more sensitive to the DM searches in the near future. The allowed mass for finding $\tilde{H}$-, $\tilde{B}$-, $\tilde{W}$- and non neutralino-like DM particles and the predictions on $⟨\sigma (\chi \chi \to ZZ,ZH,t\bar{t})v⟩$ in the indirect search are given.

    hep-phhep-exPRD(2016)·8 citations
22. 22*

    $T$-odd quark pair production and decay at $\gamma \gamma$ collider in the littlest Higgs model with $T$ parity in next-to-leading order QCD

    Liu Wen🇨🇳 · Ma Wen-Gan🇨🇳 · Guo Lei🇨🇳 · Chen Liang-Wen🇨🇳 · Chen Chang🇨🇳 · Zhang Ren-You🇨🇳

    We calculate the complete next-to-leading order (NLO) QCD corrections to the $T$-odd mirror quark pair ($q_{-}{\bar{q}}_{-}=u_{-}{\bar{u}}_{-}$, $c_{-}{\bar{c}}_{-}$, $d_{-}{\bar{d}}_{-}$, $s_{-}{\bar{s}}_{-}$) production in the littlest Higgs model with $T$-parity (LHT) at a high energy $\gamma \gamma$ collider. We present the dependence of the leading order (LO) and NLO QCD corrected cross sections on the colliding energy $\sqrt{s}$. Our calculation includes the subsequent full weak decays of the final $T$-odd mirror quarks by adopting the narrow width approximation and the exclusive 2-jet event selection criterion. We provide the LO and QCD NLO kinematic distributions of final particles. We find that the NLO QCD correction is phase space dependent and modifies the LO cross section evidently. The $K$-factor increases noticeably when $\sqrt{s}$ approaches the threshold of the on-shell $q_{-}$-pair production. We conclude that it is possible to separate the signature of the $T$-odd quark pair production from possible Standard Model background by taking proper kinematic cut.

    hep-phMod.Phys.Lett.A(2015)·0 citations
23. 23*

    Master integrals for splitting functions from differential equations in QCD

    O. Gituliar🇵🇱

    A method for calculating phase-space master integrals for the decay process $1\to n$ massless partons in QCD using integration-by-parts and differential equations techniques is discussed. The method is based on the appropriate choice of the basis for master integrals which leads to significant simplification of differential equations. We describe an algorithm how to construct the desirable basis, so that the resulting system of differential equations can be recursively solved in terms of (G)HPLs as a series in the dimensional regulator $ϵ$ to any order. We demonstrate its power by calculating master integrals for the NLO time-like splitting functions and discuss future applications of the proposed method at the NNLO precision.

    hep-phJHEP(2016)·21 citations
24. 24*

    Update of the flavour-physics constraints in the NMSSM

    Florian Domingo (IFCA / IFT)🇪🇸

    We consider the impact of several flavour-changing observables in the $B$- and the Kaon sectors on the parameter space of the NMSSM, in a minimal flavour violating version of this model. Our purpose consists in updating our previous results in arXiv:0710.3714 and designing an up-to-date flavour test for the public package NMSSMTools. We provide details concerning our implementation of the constraints in a series of brief reviews of the current status of the considered channels. Finally, we present a few consequences of these flavour constraints for the NMSSM, turning to two specific scenarios: one is characteristic of the MSSM-limit and illustrates the workings of charged-Higgs and genuinely supersymmetric contributions to flavour-changing processes; the second focus is a region where a light CP-odd Higgs is present. Strong limits are found whenever an enhancement factor - large $\tan \beta$, light $H^{\pm }$, resonant pseudoscalar - comes into play.

    hep-phEPJC(2016)·18 citations
25. 25*

    Unification of Force and Substance

    Frank Wilczek🇺🇸

    Maxwell's mature presentation of his equations emphasized the unity of electromagnetism and mechanics, subsuming both as "dynamical systems". That intuition of unity has proved both fruitful, as a source of pregnant concepts, and broadly inspiring. A deep aspect of Maxwell's work is its use of redundant potentials, and the associated requirement of gauge symmetry. Those concepts have become central to our present understanding of fundamental physics, but they can appear to be rather formal and esoteric. Here I discuss two things: The physical significance of gauge invariance, in broad terms; and some tantalizing prospects for further unification, building on that concept, that are visible on the horizon today. If those prospects are realized, Maxwell's vision of the unity of field and substance will be brought to a new level.

    hep-phhep-thphysics.hist-phPhil.Trans.Roy.Soc.Lond.A(2016)·10 citations
26. 26*

    Role of the hidden charm $N_{c\bar{c}}^{\ast }(4261)$ resonance in the ${\pi }^{-}p\to J/\psi n$ reaction

    Zhen Ouyang🇨🇳 · Li-Ping Zou🇨🇳

    We employ an effective Lagrangian approach and isobar model to investigate the role of the $N_{c\bar{c}}^{\ast }(4261)$ resonance with hidden charm in the ${\pi }^{-}p\to J/\psi n$ reaction. The total and differential cross sections of this reaction are predicted by including contributions from both $N_{c\bar{c}}^{\ast }(4261)$ and nucleon pole. It is found that the maximal value of the total cross section can exceed 11 $\mu b$ and a clear $N_{c\bar{c}}^{\ast }(4261)$ peak is visible there, well distinguished from background. As center-of-mass energy increases to about 4.8 GeV, the background makes the differential cross section for backward angles rather different. Our theoretical results would provide valuable information for looking for the $N_{c\bar{c}}^{\ast }(4261)$ resonance in future experiments.

    hep-ph3 citations
27. 27*

    Leptomeson contribution to the muon g-2

    Dmitry Zhuridov🇵🇱

    Many models on the market allow for particles carrying both lepton number and color, e.g., leptoquarks and leptogluons. Some of the models with this feature can also accommodate color-singlet leptohadrons. We have found that the long-standing discrepancy between the experimental result and the Standard Model prediction for the muon anomalous magnetic moment can be explained by the effect of leptomesons within the wide allowed range of their masses and couplings. These new particles are testable at the current run of the LHC.

    hep-phPRD(2016)·3 citations
28. 28*

    Moving forward to constrain the shear viscosity of QCD matter

    Gabriel Denicol🇺🇸 · Akihiko Monnai🇺🇸 · Bjoern Schenke🇺🇸

    We demonstrate that measurements of rapidity differential anisotropic flow in heavy ion collisions can constrain the temperature dependence of the shear viscosity to entropy density ratio {\eta}/s of QCD matter. Comparing results from hydrodynamic calculations with experimental data from RHIC, we find evidence for a small {\eta}/s $\approx$ 0.04 in the QCD cross-over region and a strong temperature dependence in the hadronic phase. A temperature independent {\eta}/s is disfavored by the data. We further show that measurements of the event-by-event flow as a function of rapidity can be used to independently constrain the initial state fluctuations in three dimensions and the temperature dependent transport properties of QCD matter.

    ↳ nucl-thhep-phnucl-exPRL(2016)·101 citations
29. 29*

    $\theta$ dependence in $SU(3)$ Yang-Mills theory from analytic continuation

    Claudio Bonati🇮🇹 · Massimo D'Elia🇮🇹 · Aurora Scapellato🇮🇹

    We investigate the topological properties of the $SU(3)$ pure gauge theory by performing numerical simulations at imaginary values of the $\theta$ parameter. By monitoring the dependence of various cumulants of the topological charge distribution on the imaginary part of $\theta$ and exploiting analytic continuation, we determine the free energy density up to the sixth order order in $\theta$, $f(\theta ,T)=f(0,T)+\frac{1}{2}\chi (T){\theta }^2(1+b_2(T){\theta }^2+b_4(T){\theta }^4+O({\theta }^6))$. That permits us to achieve determinations with improved accuracy, in particular for the higher order terms, with control over the continuum and the infinite volume extrapolations. We obtain $b_2=-0.0216(15)$ and $|b_4|\lesssim 4\times 10^{-4}$.

    ↳ hep-lathep-phhep-thPRD(2016)·74 citations
30. 30*

    Progress in Neutron EM Couplings

    Igor Strakovsky (GW)🇺🇸 · William Briscoe (GW)🇺🇸 · Alexander Kudryavtsev (ITEP/GW)🇷🇺 · Viacheslav Kulikov (ITEP)🇷🇺 · Maxim Martemianov (ITEP)🇷🇺 · Vladimir Tarasov (ITEP)🇷🇺 · Ron Workman (ITEP)🇺🇸

    An overview of the GW SAID and ITEP groups' effort to analyze pion photoproduction on the neutron-target will be given. The disentanglement of the isoscalar and isovector EM couplings of N* and Delta* resonances does require compatible data on both proton and neutron targets. The final-state interaction plays a critical role in the state-of-the-art analysis in extraction of the gn-->piN data from the deuteron target experiments. Then resonance couplings determined by the SAID PWA technique are then compared to previous findings. The neutron program is important component of the current JLab, MAMI-C, SPring-8, ELSA, and ELPH studies.

    ↳ nucl-thhep-exhep-phnucl-ex1 citation
31. 31*

    Inspecting the supernova gamma-ray burst connection with high-energy neutrinos

    Irene Tamborra🇳🇱 · Shin'ichiro Ando🇳🇱

    Long-duration gamma-ray bursts (GRBs) have been often considered as the natural evolution of some core-collapse supernovae (SNe). While GRBs with relativistic jets emit an electromagnetic signal, GRBs with mildly relativistic jets are opaque to photons and, therefore, could be detectable through neutrinos only. We discuss the possibility that successful GRBs and mildly relativistic jets belong to the same class of astrophysical transients with different Lorentz factor Gamma_b and study the production of high-energy neutrinos as a function of Gamma_b, by including both proton-photon and proton-proton interactions. By assuming a SN-GRB connection, we find that the diffuse neutrino emission from optically thick jets with Lorentz factors lower than the ones of successful GRBs can be one of the main components of the observed IceCube high-energy neutrino flux. Moreover, under the assumption that all these jets belong to the same class of astrophysical transients, we show that the IceCube high-energy neutrino data provide indirect constraints on the rate of non-successful jets, favoring a local rate lower than tens of percent of the local SN rate. These limits are currently comparable to the ones obtained in dedicated searches on choked sources and are expected to become tighter with accumulation of more high-energy neutrino data.

    ↳ astro-ph.HEhep-phPRD(2016)·81 citations
32. 32*

    Positive Energy Conditions in 4D Conformal Field Theory

    Kara Farnsworth🇺🇸 · Markus A. Luty🇺🇸 · Valentina Prilepina🇺🇸

    We argue that all consistent 4D quantum field theories obey a spacetime-averaged weak energy inequality $⟨T^{00}⟩\ge -C/L^4$, where $L$ is the size of the smearing region, and $C$ is a positive constant that depends on the theory. If this condition is violated, the theory has states that are indistinguishable from states of negative total energy by any local measurement, and we expect instabilities or other inconsistencies. We apply this condition to 4D conformal field theories, and find that it places constraints on the OPE coefficients of the theory. The constraints we find are weaker than the "conformal collider" constraints of Hofman and Maldacena. We speculate that there may be theories that violate the Hofman-Maldacena bounds, but satisfy our bounds. In 3D CFTs, the only constraint we find is equivalent to the positivity of 2-point function of the energy-momentum tensor, which follows from unitarity. Our calculations are performed using momentum-space Wightman functions, which are remarkably simple functions of momenta, and may be of interest in their own right.

    ↳ hep-thhep-phJHEP(2016)·14 citations
33. 33*

    The Spatial Morphology of the Secondary Emission in the Galactic Center Gamma-Ray Excess

    Thomas Lacroix🇫🇷 · Oscar Macias🇺🇸 · Chris Gordon🇳🇿 · Paolo Panci🇫🇷 · Celine Boehm🇬🇧 · Joseph Silk🇫🇷

    Excess GeV gamma rays from the Galactic Center (GC) have been measured with the Fermi Large Area Telescope (LAT). The presence of the GC excess (GCE) appears to be robust with respect to changes in the diffuse galactic background modeling. The three main proposals for the GCE are an unresolved population of millisecond pulsars (MSPs), outbursts of cosmic rays from the GC region, and self-annihilating dark matter (DM). The injection of secondary electrons and positrons into the interstellar medium (ISM) by an unresolved population of MSPs or DM annihilations can lead to observable gamma-ray emission via inverse Compton scattering or bremsstrahlung. Here we investigate how to determine whether secondaries are important in a model for the GCE. We develop a method of testing model fit which accounts for the different spatial morphologies of the secondary emission. We examine several models which give secondary emission and illustrate a case where a broadband analysis is not sufficient to determine the need for secondary emission.

    ↳ astro-ph.HEastro-ph.COastro-ph.GAhep-phPRD(2016)·29 citations
34. 34*

    $\bar{K}$ induced formation of the $f_0(980)$ and $a_0(980)$ resonances on proton targets

    Ju-Jun Xie🇨🇳 · We-Hong Liang🇨🇳 · Eulogio Oset🇪🇸

    We perform a calculation of the cross section for nine reactions induced by $\bar{K}$ scattering on protons. The reactions studied are $K^{-}p\to \Lambda {\pi }^{+}{\pi }^{-}$, $K^{-}p\to {\Sigma }^0{\pi }^{+}{\pi }^{-}$, $K^{-}p\to \Lambda {\pi }^0\eta$, $K^{-}p\to {\Sigma }^0{\pi }^0\eta$, $K^{-}p\to {\Sigma }^{+}{\pi }^{-}\eta$, ${\bar{K}}^{0}p\to \Lambda {\pi }^{+}\eta$, ${\bar{K}}^{0}p\to {\Sigma }^0{\pi }^{+}\eta$, ${\bar{K}}^{0}p\to {\Sigma }^{+}{\pi }^{+}{\pi }^{-}$, ${\bar{K}}^{0}p\to {\Sigma }^{+}{\pi }^0\eta$. We find that in the reactions producing ${\pi }^{+}{\pi }^{-}$ a clear peak for the $f_0(980)$ resonance is found, while no trace of $f_0(500)$ appears. Similarly, in the cases of $\pi \eta$ production a strong peak is found for the $a_0(980)$ resonance, with the characteristic strong cusp shape. Cross sections and invariant mass distributions are evaluated which should serve, comparing with future data, to test the dynamics of the chiral unitary approach used for the evaluations and the nature of these resonances.

    ↳ nucl-thhep-phPRC(2016)·6 citations
35. 35*

    Hawking radiation of charged Einstein-aether black holes at both Killing and universal horizons

    Chikun Ding🇺🇸 · Anzhong Wang🇨🇳 · Xinwen Wang🇺🇸 · Tao Zhu🇺🇸

    We study analytically quantum tunneling of relativistic and non-relativistic particles at both Killing and universal horizons of Einstein-Maxwell-aether black holes, after high-order curvature corrections are taken into account, for which the dispersion relation of the particles becomes nonlinear. Our results at the Killing horizons confirm the previous ones, i.e., at high frequencies the corresponding radiation remains thermal and the nonlinearity of the dispersion does not alter the Hawking radiation significantly. In contrary, non-relativistic particles are created at universal horizons and are radiated out to infinity. The radiation also has a thermal spectrum, and the corresponding temperature takes the form, $T_{UH}^z=2{\kappa }_{UH}(z-1)/(2\pi z)$, where $z$ denotes the power of the leading term in the nonlinear dispersion relation, ${\kappa }_{UH}$ is the surface gravity of the universal horizon, defined by peering behavior of ray trajectories at the universal horizon. We also study the Smarr formula by assuming that: (a) the entropy is proportional to the area of the universal horizon, and (b) the first law of black hole thermodynamics holds, whereby we derive the Smarr mass, which in general is different from the total mass obtained at infinity. This indicates that one or both of these assumptions must be modified.

    ↳ gr-qcastro-ph.GAhep-phhep-thNPB(2016)·45 citations
36. 36*

    Magnetic Properties of Quantized Vortices in Neutron ${}^3{P}_2$ Superfluids in Neutron Stars

    Kota Masuda🇯🇵 · Muneto Nitta🇯🇵

    We discuss quantized vortices in neutron ${}^3{P}_2$ superfluids, which are believed to realize in high density neutron matter such as neutron stars. By using the Ginzburg-Landau free energy for ${}^3{P}_2$ superfluids, we determine the ground state in the absence and presence of the external magnetic field, and numerically construct ${}^3{P}_2$ quantized vortices in the absence and presence of the external magnetic field along the vortex axis (poloidal) or angular direction (toroidal). We find in certain situations the spontaneous magnetization of the vortex core, whose typical magnitude is about $10^{7-8}$ Gauss, but the net magnetic field in a neutron star is negligible because of the ratio of the vortex core size $\sim 10$fm and the intervortex distance $\sim 10^{-6}$m in a vortex lattice.

    ↳ nucl-thastro-ph.HEcond-mat.otherhep-phPRC(2016)·33 citations
37. 37*

    Bosonic structure of realistic SO(10) SUSY cosmic strings

    Erwan Allys🇫🇷

    We study the bosonic structure of $F$-term Nambu-Goto cosmic strings forming in a realistic SO(10) implementation, assuming standard hybrid inflation. We describe the supersymmetric grand unified theory, and its spontaneous symmetry breaking scheme in parallel with the inflationary process. We also write the explicit tensor formulation of its scalar sector, focusing on the sub-representations singlet under the standard model, which is sufficient to describe the string structure. We then introduce an ansatz for abelian cosmic strings, discussing in details the hypothesis, and write down the field equations and boundary conditions. Finally, after doing a perturbative study of the model, we present and discuss the results obtained with numerical solutions of the string structure.

    ↳ gr-qchep-phhep-thPRD(2016)·14 citations
38. 38*

    Light-cone distribution amplitudes of the baryon octet

    Gunnar S. Bali🇩🇪 · Vladimir M. Braun🇩🇪 · Meinulf Göckeler🇩🇪 · Michael Gruber🇩🇪 · Fabian Hutzler🇩🇪 · Andreas Schäfer🇩🇪 · Rainer W. Schiel🇩🇪 · Jakob Simeth🇩🇪 · Wolfgang Söldner🇩🇪 · Andre Sternbeck🇩🇪 · Philipp Wein🇩🇪

    We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using $N_f=2+1$ flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplitudes are observed.

    ↳ hep-lathep-phJHEP(2016)·55 citations
39. 39*

    A simple model for the evolution of a non-Abelian cosmic string network

    G. Cella🇮🇹 · M. Pieroni🇫🇷

    In this paper we present the results of numerical simulations intended to study the behavior of non-Abelian cosmic strings networks. In particular we are interested in discussing the variations in the asymptotic behavior of the system as we variate the number of generators for the topological defects. A simple model which should generate cosmic strings is presented and its lattice discretization is discussed. The evolution of the generated cosmic string networks is then studied for different values for the number of generators for the topological defects. Scaling solution appears to be approached in most cases and we present an argument to justify the lack of scaling for the residual cases.

    ↳ astro-ph.COgr-qchep-phJCAP(2016)·0 citations
40. 40*

    A general mass term for bigravity

    Giulia Cusin🇨🇭 · Ruth Durrer🇨🇭 · Pietro Guarato🇨🇭 · Mariele Motta🇨🇭

    We introduce a new formalism to study perturbations of Hassan-Rosen bigravity theory, around general backgrounds for the two dynamical metrics. In particular, we derive the general expression for the mass term of the perturbations and we explicitly compute it for cosmological settings. We study tensor perturbations in a specific branch of bigravity using this formalism. We show that the tensor sector is affected by a late-time instability, which sets in when the mass matrix is no longer positive definite.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2016)·32 citations
41. 41*

    Power spectrum of flow fluctuations in relativistic heavy-ion collisions

    P. S. Saumia🇮🇳 · Ajit M. Srivastava🇮🇳

    We carry out hydrodynamical simulation of the evolution of fluid in relativistic heavy-ion collisions with random initial fluctuations. The time evolution of power spectrum of momentum anisotropies shows very strong correspondence with the physics of cosmic microwave anisotropies as was earlier predicted by some of us. In particular our results demonstrate suppression of superhorizon fluctuations and the correspondence between the location of the first peak in the power spectrum of momentum anisotropies and the length scale of fluctuations and expected freezeout time scale (more precisely, the sound horizon size at freezeout).

    ↳ nucl-thastro-ph.COhep-phnucl-exMod.Phys.Lett.A(2016)·6 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.