Wed·Feb 14, 2018Wednesday·February 14, 2018

1. 01*

   Future Deep Inelastic Scattering with the LHeC

   Max Klein🇬🇧

   For nearly a decade, Guido Altarelli accompanied the Large Hadron electron Collider project, as invited speaker, referee and member of the International Advisory Committee. This text summarises the status and prospects of the development of the LHeC, with admiration for a one-time scientist and singular leader whom I met first nearly 40 years ago under the sun shining for the "Herceg Novi School" in Kupari, where we both lectured about the beautiful science of Deep Inelastic Scattering and enjoyed life under a yellow moon.

   hep-phhep-ex33 citations
2. 02*

   Higgs Pair Production at Future Hadron Colliders: From Kinematics to Dynamics

   Dorival Goncalves🇺🇸 · Tao Han🇺🇸 · Felix Kling🇺🇸 · Tilman Plehn🇩🇪 · Michihisa Takeuchi🇯🇵

   The measurement of the triple Higgs coupling is a key benchmark for the LHC and future colliders. It directly probes the Higgs potential and its fundamental properties in connection to new physics beyond the Standard Model. There exist two phase space regions with an enhanced sensitivity to the Higgs self-coupling, the Higgs pair production threshold and an intermediate top pair threshold. We show how the invariant mass distribution of the Higgs pair offers a systematic way to extract the Higgs self-coupling, focusing on the leading channel $pp\to hh+X\to b\bar{b}\gamma \gamma +X$. We utilize new features of the signal events at higher energies and estimate the potential of a high-energy upgrade of the LHC and a future hadron collider with realistic simulations. We find that the high-energy upgrade of the LHC to 27 TeV would reach a 5$\sigma$ observation with an integrated luminosity of 2.5 ab${}^{-1}$. It would have the potential to reach 15% (30%) accuracy at the 68% (95%) confidence level to determine the SM Higgs boson self-coupling. A future 100 TeV collider could improve the self-coupling measurement to better than 5% (10%) at the 68% (95%) confidence level.

   hep-phhep-exPRD(2018)·96 citations
3. 03*

   On the Light Massive Flavor Dependence of the Top Quark Mass

   André H. Hoang🇦🇹 · Christopher Lepenik🇦🇹 · Moritz Preisser🇦🇹

   We provide a systematic renormalization group formalism to study the mass effects in the relation of the pole mass and short-distance masses such as the $\overline{\mathrm{MS}}$ mass of a heavy quark $Q$, coming from virtual loop insertions of massive quarks lighter than $Q$ with the main focus on the top quark. The formalism reflects the constraints from heavy quark symmetry and entails a combined matching and evolution procedure that allows to disentangle and successively integrate out the corrections coming from the lighter massive quarks and the momentum regions between them and also to precisely control the large order asymptotic behavior. The formalism is used to study the asymptotic behavior of light massive flavor contributions and is applied to predict the $\mathcal{O}({\alpha }_s^4)$ virtual quark mass corrections, calculate the pole mass differences for massive quark flavors with a precision of around 20 MeV, and determine the pole mass ambiguity which amounts to 250 MeV in the physical case of three massless quark flavors.

   hep-phPoS(2018)·2 citations
4. 04*

   Polarization observables and T-noninvariance in the weak charged current induced electron proton scattering

   A. Fatima🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳

   In this work, we have studied the total scattering cross section ($\sigma$), differential scattering cross section ($d\sigma /d{Q}^2$) as well as the longitudinal ($P_L(E_e,Q^2)$), perpendicular ($P_P(E_e,Q^2)$), and transverse ($P_T(E_e,Q^2)$) components of the polarization of the final hadron ($n$, $\Lambda$ and ${\Sigma }^0$) produced in the electron proton scattering induced by the weak charged current. We have not assumed T-invariance which allows the transverse component of the hadron polarization perpendicular to the production plane to be non-zero. The numerical results are presented for all the above observables and their dependence on the axial vector form factor and the weak electric form factor are discussed. The present study enables the determination of the axial vector nucleon-hyperon transition form factors at high $Q^2$ in the strangeness sector which can provide test of the symmetries of the weak hadronic currents like T-invariance and SU(3) symmetry while assuming the hypothesis of conserved vector current and partial conservation of axial vector current.

   hep-phEPJA(2018)·19 citations
5. 05*

   Required sensitivity to search the neutrinoless double beta decay in ${}^{124}Sn$

   Manoj Kumar Singh · Lakhwinder Singh · Vivek Sharma🇹🇼 · Manoj Kumar Singh · Abhishek Kumar🇮🇳 · Akash Pandey🇮🇳 · Venktesh Singh · Henry Tsz-King Wong🇹🇼

   \textbf{T}he \textbf{IN}dia's \textbf{TIN} (TIN.TIN) detector is under development in the search for neutrinoless double-$\beta$ decay (0$\nu \beta \beta$) using 90\% enriched ${}^{124}$Sn isotope as the target mass. This detector will be housed in the upcoming underground facility of the \textbf{I}ndia based \textbf{N}eutrino \textbf{O}bservatory. We present the most important experimental parameters that would be used in the study of required sensitivity for the TIN.TIN experiment to probe the neutrino mass hierarchy. The sensitivity of the TIN.TIN detector in the presence of sole two neutrino double-$\beta$ decay (2$\nu \beta \beta$) decay background is studied at various energy resolutions. The most optimistic and pessimistic scenario to probe the neutrino mass hierarchy at 3$\sigma$ sensitivity level and 90\% C.L. is also discussed.

   hep-phphysics.ins-detIndian J.Phys.(2019)·8 citations
6. 06*

   Ratios of vector and pseudoscalar $B$ meson decay constants in the light-cone quark model

   Nisha Dhiman🇮🇳 · Harleen Dahiya🇮🇳

   We study the decay constants of pseudoscalar and vector $B$ meson in the framework of light-cone quark model (LCQM). We apply the variational method to the relativistic Hamiltonian with the Gaussian-type trial wave function to obtain the values of $\beta$ (scale parameter). Then with the help of known values of constituent quark masses, we obtain the numerical results for the decay constants $f_P$ and $f_V$, respectively. We compare our numerical results with the existing experimental data.

   hep-phFew Body Syst.(2018)·1 citation
7. 07*

   The minimal type-I seesaw model with maximally-restricted texture zeros

   D. M. Barreiros🇵🇹 · R. G. Felipe🇵🇹 · F. R. Joaquim🇵🇹

   In the context of Standard Model (SM) extensions, the seesaw mechanism provides the most natural explanation for the smallness of neutrino masses. In this work we consider the most economical type-I seesaw realization in which two right-handed neutrinos are added to the SM field content. For the sake of predictability, we impose the maximum number of texture zeros in the lepton Yukawa and mass matrices. All possible patterns are analyzed in the light of the most recent neutrino oscillation data, and predictions for leptonic CP violation are presented. We conclude that, in the charged-lepton mass basis, eight different texture combinations are compatible with neutrino data at $1\sigma$, all of them for an inverted-hierarchical neutrino mass spectrum. Four of these cases predict a CP-violating Dirac phase close to $3\pi /2$, which is around the current best-fit value from global analysis of neutrino oscillation data. If one further reduces the number of free parameters by considering three equal elements in the Dirac neutrino Yukawa coupling matrix, several texture combinations are still compatible with data but only at $3\sigma$. For all viable textures, the baryon asymmetry of the Universe is computed in the context of thermal leptogenesis, assuming (mildly) hierarchical heavy Majorana neutrino masses $M_{1,2}$. It is shown that the flavored regime is ruled out, while the unflavored one requires $M_1\sim 10^{14}$ GeV.

   hep-phPRD(2018)·34 citations
8. 08*

   Studying the bound state of the $B\bar{K}$ system in the Bethe-Salpeter formalism

   Zhen-Yang Wang🇨🇳 · Jing-Juan Qi🇨🇳 · Xin-Heng Guo🇨🇳

   In this work, we study the $B\bar{K}$ molecule in the Bethe-Salpeter (BS) equation approach. With the kernel containing one-particle-exchange diagrams and introducing two different form factors (monopole form factor and dipole form factor) in the vertex, we solve the BS equation numerically in the covariant instantaneous approximation. We investigate the isoscalar and isovector $B\bar{K}$ systems, and we find $X(5568)$ cannot be a $B\bar{K}$ molecule.

   hep-phAdv.High Energy Phys.(2019)·9 citations
9. 09*

   Exclusive vector meson photoproduction in fixed - target collisions at the LHC

   V. P. Goncalves🇧🇷 · M. M. Jaime🇧🇷

   The exclusive $\rho$, $\omega$ and $J/\Psi$ photoproduction in fixed - target collisions at the LHC is investigated. We estimate, for the first time, the rapidity and transverse momentum distributions of the vector meson photoproduction in $pHe$, $pAr$, $PbHe$ and $PbAr$ fixed - target collisions at the LHC using the STARlight Monte Carlo and present our results for the total cross sections. Predictions for the kinematical range probed by the LHCb detector are also presented. Our results indicate that the experimental analysis of this process in fixed - target collisions at the LHC is feasible. Such future analysis will probe the QCD dynamics in a kinematical range complementary to that studied in the collider mode.

   hep-phhep-exnucl-exnucl-thEPJC(2018)·15 citations
10. 10*

    Numerical estimate of minimal active-sterile neutrino mixing for sterile neutrinos at GeV scale

    Igor Krasnov🇷🇺 · Timofey Grigorin-Ryabov🇷🇺

    Seesaw mechanism constrains from below mixing between active and sterile neutrinos for fixed sterile neutrino masses. Signal events associated with sterile neutrino decays inside a detector at fixed target experiment are suppressed by the mixing angle to the power of four. Therefore sensitivity of experiments such as SHiP and DUNE should take into account minimal possible values of the mixing angles. We extend the previous study of this subject arXiv:1312.2887 to a more general case of non-zero CP-violating phases in the neutrino sector. Namely, we provide numerical estimate of minimal value of mixing angles between active neutrinos and two sterile neutrinos with the third sterile neutrino playing no noticeable role in the mixing. Thus we obtain a sensitivity needed to fully explore the seesaw type I mechanism for sterile neutrinos with masses below 2 GeV, and one undetectable sterile neutrino that is relevant for the fixed-target experiments. Remarkably, we observe a strong dependence of this result on the lightest active neutrino mass and the neutrino mass hierarchy, not only on the values of CP-violating phases themselves. All these effects sum up to push the limit of experimental confirmation of sterile-active neutrino mixing by several orders of magnitude below the results of arXiv:1312.2887 from $10^{-10}$ - $10^{-11}$ down to $10^{-12}$ and even to $10^{-20}$ in parts of parameter space; nonzero CP-violating phases are responsible for that.

    hep-phEPJ Web Conf.(2018)·3 citations
11. 11*

    A study on a minimally broken residual TBM-Klein symmetry with its implications on flavoured leptogenesis and ultra high energy neutrino flux ratios

    Rome Samanta🇮🇳 · Mainak Chakraborty🇮🇳

    We present a systematic study on minimally perturbed neutrino mass matrices which at the leading order give rise to Tri-BiMaximal (TBM) mixing due to a residual ${\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\mu \tau }$ Klein symmetry in the neutrino mass term of the low energy effective seesaw Lagrangian. Considering only the breaking of ${\mathbb{Z}}_2^{\mu \tau }$ with two relevant breaking parameters (${ϵ}_{4,6}^{\prime }$), after a comprehensive numerical analysis, we show that the phenomenologically viable case in this scenario is a special case of TM1 mixing. For this class of models, from the phenomenological perspective, one always needs large breaking (more than $45\%$) in one of the breaking parameters. However, to be consistent the maximal mixing of ${\theta }_{23}$, while more than $35\%$ breaking is needed in the other, a range $49.4^{\circ }-53^{\circ }$ and $38^{\circ }-40^{\circ }$ could be probed allowing breaking up to $25\%$ in the same parameter. Thus though this model cannot distinguish the octant of ${\theta }_{23}$, non-maximal mixing is preferred from the viewpoint of small breaking. The model is also interesting from leptogenesis perspective. Unlike the standard $N_1$-leptogenesis scenario, here all the RH neutrinos contribute to lepton asymmetry due to the small mass splitting controlled by the ${\mathbb{Z}}_2^{\mu \tau }$ breaking parameters. Inclusion of flavour coupling effects (In general, which have been partially included in all the leptogenesis studies in perturbed TBM framework) makes our analysis and results pertaining to a successful leptogenesis more accurate than any other studies in existing literature. Finally, in the context of recent discovery of the ultra high energy (UHE) neutrino events at IceCube, assuming UHE neutrinos originate from purely astrophysical sources, we obtain prediction on the neutrino flux ratios at neutrino telescopes.

    hep-phJCAP(2019)·13 citations
12. 12*

    Resonant production of dark photons in positron beam dump experiments

    Enrico Nardi🇮🇹 · Cristian D. R. Carvajal🇨🇴 · Anish Ghoshal🇮🇹 · Davide Meloni🇮🇹 · Mauro Raggi🇮🇹

    Positrons beam dump experiments have unique features to search for very narrow resonances coupled superweakly to $e^{+}{e}^{-}$ pairs. Due to the continue loss of energy from soft photon bremsstrahlung, in the first few radiation lengths of the dump a positron beam can continuously scan for resonant production of new resonances via $e^{+}$ annihilation off an atomic $e^{-}$ in the target. In the case of a dark photon $A^{\prime }$ kinetically mixed with the photon, this production mode is of first order in the electromagnetic coupling $\alpha$, and thus parametrically enhanced with respect to the $O({\alpha }^2)$ $e^{+}{e}^{-}\to \gamma A^{\prime }$ production mode and to the $O({\alpha }^3)$ $A^{\prime }$ bremsstrahlung in $e^{-}-$nucleon scattering so far considered. If the lifetime is sufficiently long to allow the $A^{\prime }$ to exit the dump, $A^{\prime }\to e^{+}{e}^{-}$ decays could be easily detected and distinguished from backgrounds. We explore the foreseeable sensitivity of the Frascati PADME experiment in searching with this technique for the $17$MeV dark photon invoked to explain the ${}^8$Be anomaly in nuclear transitions.

    hep-phhep-exPRD(2018)·77 citations
13. 13*

    How blind are underground and surface detectors to strongly interacting Dark Matter?

    Timon Emken🇩🇰 · Chris Kouvaris🇩🇰

    Above a critical dark matter-nucleus scattering cross section any terrestrial direct detection experiment loses sensitivity to dark matter, since the Earth crust, atmosphere, and potential shielding layers start to block off the dark matter particles. This critical cross section is commonly determined by describing the average energy loss of the dark matter particles analytically. However, this treatment overestimates the stopping power of the Earth crust. Therefore the obtained bounds should be considered as conservative. We perform Monte Carlo simulations to determine the precise value of the critical cross section for various direct detection experiments and compare them to other dark matter constraints in the low mass regime. In this region we find parameter space where typical underground and surface detectors are completely blind to dark matter. This "hole" in the parameter space can hardly be closed with an increase in the detector exposure. Dedicated surface or high-altitude experiments may be the only way to directly probe this part of the parameter space.

    hep-phastro-ph.COhep-exPRD(2018)·147 citations
14. 14*

    Heavy Ion Collisions: The Big Picture, and the Big Questions

    Wit Busza🇺🇸 · Krishna Rajagopal🇺🇸 · Wilke van der Schee🇺🇸

    Heavy ion collisions quickly form a droplet of quark-gluon plasma (QGP) with a remarkably small viscosity. We give an accessible introduction to how to study this smallest and hottest droplet of liquid made on earth and why it is so interesting. The physics of heavy ions ranges from highly energetic quarks and gluons described by perturbative QCD to a bath of strongly interacting gluons at lower energy scales. These gluons quickly thermalize and form QGP, while the energetic partons traverse this plasma and end in a shower of particles called jets. Analyzing the final particles in a variety of different ways allows us to study the properties of QGP and the complex dynamics of multi-scale processes in QCD which govern its formation and evolution, providing what is perhaps the simplest form of complex quantum matter that we know of. Much remains to be understood, and throughout the review big open questions will be encountered.

    hep-phhep-thnucl-exnucl-thAnn.Rev.Nucl.Part.Sci.(2018)·1159 citations
15. 15*

    $\Delta L=3$ processes: Proton decay and LHC

    Renato M. Fonseca🇪🇸 · Martin Hirsch🇪🇸 · Rahul Srivastava🇪🇸

    We discuss lepton number violation in three units. From an effective field theory point of view, $\Delta L=3$ processes can only arise from dimension 9 or higher operators. These operators also violate baryon number, hence many of them will induce proton decay. Given the high dimensionality of these operators, in order to have a proton half-life in the observable range, the new physics associated to $\Delta L=3$ processes should be at a scale as low as 1 TeV. This opens up the possibility of searching for such processes not only in proton decay experiments but also at the LHC. In this work we analyze the relevant $d=9,11,13$ operators which violate lepton number in three units. We then construct one simple concrete model with interesting low- and high-energy phenomenology.

    hep-phhep-exPRD(2018)·30 citations
16. 16*

    Distinguishing rotating Kiselev black hole from naked singularity using spin precession of test gyroscope

    Muhammad Rizwan🇵🇰 · Mubasher Jamil🇵🇰 · Anzhong Wang🇨🇳

    We study the critical values of the quintessential and spin parameters, to distinguish a rotating Kiselev black hole (RKBH) from a naked singularity. For any value of the dimensionless quintessential parameter ${\omega }_q\in (-1,-1/3)$, when increasing the value of quintessential parameter $\alpha$, the size of the event horizon increases, whereas the size of the outer horizon decreases. We then study the spin precession of a test gyroscope attached to a stationary observer in this spacetime. Using the spin precessions we differentiate black holes from naked singularities. If the precession frequency becomes large, as approaching to the central object in the quintessential field along any direction, then the spacetime is a black hole. A spacetime will contain a naked singularity if the precession frequency remains finite everywhere except at the singularity itself. Finally, we study the Lense-Thirring precession frequency for rotating Kiseleb black hole and the geodetic precession for Kiselev black hole.

    ↳ gr-qchep-phhep-thPRD(2018)·34 citations
17. 17*

    Constraints on Einstein-aether theory after GW170817

    Jacob Oost🇺🇸 · Shinji Mukohyama🇯🇵 · Anzhong Wang🇺🇸

    In this paper, we carry out a systematic analysis of the theoretical and observational constraints on the dimensionless coupling constants $c_i$ ($i=1,2,3,4$) of the Einstein-aether theory, taking into account the events GW170817 and GRB 170817A. The combination of these events restricts the deviation of the speed $c_T$ of the spin-2 graviton to the range, $-3\times 10^{-15}<c_T-1<7\times 10^{-16}$, which for the Einstein-aether theory implies $\left|c_{13}\right|\le 10^{-15}$ with $c_{ij}\equiv c_i+c_j$. The rest of the constraints are divided into two groups: those on the ($c_1,c_{14}$)-plane and those on the ($c_2,c_{14}$)-plane, except the strong-field constraints. The latter depend on the sensitivities ${\sigma }_{\text{ae}}$ of neutron stars, which are not known at present in the new ranges of the parameters found in this paper.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2018)·153 citations
18. 18*

    Strangeness $S=-1$ hyperon-nucleon interactions: chiral effective field theory vs. lattice QCD

    Jing Song🇨🇳 · Kai-Wen Li🇨🇳 · Li-Sheng Geng🇨🇳

    Hyperon-nucleon interactions serve as basic inputs to studies of hypernuclear physics and dense (neutron) stars. Unfortunately, a precise understanding of these important quantities have lagged far behind that of the nucleon-nucleon interaction due to lack of high precision experimental data. Historically, hyperon-nucleon interactions are either formulated in quark models or meson exchange models. In recent years, lattice QCD simulations and chiral effective field theory approaches start to offer new insights from first principles. In the present work, we contrast the state of art lattice QCD simulations with the latest chiral hyperon-nucleon forces and show that the leading order relativistic chiral results can already describe the lattice QCD data reasonably well. Given the fact that the lattice QCD simulations are performed with pion masses ranging from the (almost) physical point to 700 MeV, such studies provide a highly non-trivial check on both the chiral effective field theory approaches as well as lattice QCD simulations. Nevertheless more precise lattice QCD simulations are eagerly needed to refine our understanding of hyperon-nucleon interactions.

    ↳ nucl-thhep-lathep-phPRC(2018)·41 citations
19. 19*

    Pseudorapidity distribution and decorrelation of anisotropic flow within CLVisc hydrodynamics

    Long-Gang Pang🇺🇸 · Hannah Petersen🇩🇪 · Xin-Nian Wang🇨🇳

    Studies of fluctuations and correlations of soft hadrons and hard and electromagnetic probes of the dense and strongly interacting medium require event-by-event hydrodynamic simulations of high-energy heavy-ion collisions that are computing intensive. We develop a (3+1)D viscous hydrodynamic model -- CLVisc that is parallelized on Graphics Processing Unit (GPU) using Open Computing Language (OpenCL) with 60 times performance increase for space-time evolution and more than 120 times for the Cooper-Frye particlization relative to that without GPU parallelization. The pseudo-rapidity dependence of anisotropic flow $v_n(\eta )$ are then computed in CLVisc with initial conditions given by the A Multi-Phase Transport (AMPT) model, with energy density fluctuations both in the transverse plane and along the longitudinal direction. Although the magnitude of $v_n(\eta )$ and the ratios between $v_2(\eta )$ and $v_3(\eta )$ are sensitive to the effective shear viscosity over entropy density ratio ${\eta }_v/s$, the shape of the $v_n(\eta )$ distributions in $\eta$ do not depend on the value of ${\eta }_v/s$. The decorrelation of $v_n$ along the pseudo-rapidity direction due to the twist and fluctuation of the event-planes in the initial parton density distributions is also studied. The decorrelation observable $r_n({\eta }^a,{\eta }^b)$ between $v_n\{-{\eta }^a\}$ and $v_n\{{\eta }^a\}$ with the auxiliary reference window ${\eta }^b$ is found not sensitive to ${\eta }_v/s$ when there is no initial fluid velocity. For small ${\eta }_v/s$, the initial fluid velocity from mini-jet partons introduces sizable splitting of $r_n({\eta }^a,{\eta }^b)$ between the two reference rapidity windows ${\eta }^b\in [3,4]$ and ${\eta }^b\in [4.4,5.0]$, as has been observed in experiment. The implementation of CLVisc and guidelines on how to efficiently parallelize scientific programs on GPUs are also provided.

    ↳ nucl-thhep-phphysics.comp-phphysics.flu-dynPRC(2018)·213 citations
20. 20*

    Cosmological bounds on neutrino statistics

    P.F. de Salas🇪🇸 · S. Gariazzo🇪🇸 · M. Laveder🇮🇹 · S. Pastor🇪🇸 · O. Pisanti🇮🇹 · N. Truong🇭🇺

    We consider the phenomenological implications of the violation of the Pauli exclusion principle for neutrinos, focusing on cosmological observables such as the spectrum of Cosmic Microwave Background anisotropies, Baryon Acoustic Oscillations and the primordial abundances of light elements. Neutrinos that behave (at least partly) as bosonic particles have a modified equilibrium distribution function that implies a different influence on the evolution of the Universe that, in the case of massive neutrinos, can not be simply parametrized by a change in the effective number of neutrinos. Our results show that, despite the precision of the available cosmological data, only very weak bounds can be obtained on neutrino statistics, disfavouring a more bosonic behaviour at less than $2\sigma$.

    ↳ astro-ph.COhep-phJCAP(2018)·12 citations
21. 21*

    Impacts of gravitational-wave standard siren observation of the Einstein Telescope on weighing neutrinos in cosmology

    Ling-Feng Wang🇨🇳 · Xuan-Neng Zhang🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳

    We investigate the impacts of the gravitational-wave (GW) standard siren observation of the Einstein Telescope (ET) on constraining the total neutrino mass. We simulate 1000 GW events that would be observed by the ET in its 10-year observation by taking the standard $\Lambda$CDM cosmology as a fiducial model. We combine the simulated GW data with other cosmological observations including cosmic microwave background (CMB), baryon acoustic oscillations (BAO), and type Ia supernovae (SN). We consider three mass hierarchy cases for the neutrino mass, i.e., normal hierarchy (NH), inverted hierarchy (IH), and degenerate hierarchy (DH). Using Planck+BAO+SN, we obtain $\sum m_{\nu }<0.175$ eV for the NH case, $\sum m_{\nu }<0.200$ eV for the IH case, and $\sum m_{\nu }<0.136$ eV for the DH case. After considering the GW data, i.e., using Planck+BAO+SN+GW, the constraint results become $\sum m_{\nu }<0.151$ eV for the NH case, $\sum m_{\nu }<0.185$ eV for the IH case, and $\sum m_{\nu }<0.122$ eV for the DH case. We find that the GW data can help reduce the upper limits of $\sum m_{\nu }$ by 13.7%, 7.5%, and 10.3% for the NH, IH, and DH cases, respectively. In addition, we find that the GW data can also help break the degeneracies between $\sum m_{\nu }$ and other parameters. We show that the GW data of the ET could greatly improve the constraint accuracies of cosmological parameters.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2018)·102 citations
22. 22*

    The P2 Experiment - A future high-precision measurement of the electroweak mixing angle at low momentum transfer

    Dominik Becker · Razvan Bucoveanu · Carsten Grzesik · Ruth Kempf · Kathrin Imai · Matthias Molitor · Alexey Tyukin · Marco Zimmermann · David Armstrong · Kurt Aulenbacher · Sebastian Baunack · Rakitha Beminiwattha and 33 other authors

    This article describes the future P2 parity-violating electron scattering facility at the upcoming MESA accelerator in Mainz. The physics program of the facility comprises indirect, high precision search for physics beyond the Standard Model, measurement of the neutron distribution in nuclear physics, single-spin asymmetries stemming from two-photon exchange and a possible future extension to the measurement of hadronic parity violation. The first measurement of the P2 experiment aims for a high precision determination of the weak mixing angle to a precision of 0.14% at a four-momentum transfer of Q^2 = 4.5 10^{-3} GeV^2. The accuracy is comparable to existing measurements at the Z pole. It comprises a sensitive test of the standard model up to a mass scale of 50 TeV, extendable to 70 TeV. This requires a measurement of the parity violating cross section asymmetry -39.94 10^{-9} in the elastic electron-proton scattering with a total accuracy of 0.56 10^-9 (1.4 %) in 10,000 h of 150 \micro A polarized electron beam impinging on a 60 cm liquid H_2 target allowing for an extraction of the weak charge of the proton which is directly connected to the weak mixing angle. Contributions from gamma Z-box graphs become small at the small beam energy of 155 MeV. The size of the asymmetry is the smallest asymmetry ever measured in electron scattering with an unprecedented goal for the accuracy. We report here on the conceptual design of the P2 spectrometer, its Cherenkov detectors, the integrating read-out electronics as well as the ultra-thin, fast tracking detectors. There has been substantial theory work done in preparation of the determination of the weak mixing angle. The further physics program in particle and nuclear physics is described as well.

    ↳ nucl-exhep-exhep-phphysics.ins-detEPJA(2018)·234 citations
23. 23*

    Perfect fluid Lagrangian and its cosmological implications in theories of gravity with nonminimally coupled matter fields

    P. P. Avelino🇵🇹 · R. P. L. Azevedo🇵🇹

    In this paper we show that the on-shell Lagrangian of a perfect fluid depends on microscopic properties of the fluid, giving specific examples of perfect fluids with different on-shell Lagrangians but with the same energy-momentum tensor. We demonstrate that if the fluid is constituted by localized concentrations of energy with fixed rest mass and structure (solitons) then the average on-shell Lagrangian of a perfect fluid is given by ${\mathcal{L}}_m=T$, where $T$ is the trace of the energy-momentum tensor. We show that our results have profound implications for theories of gravity where the matter Lagrangian appears explicitly in the equations of motion of the gravitational and matter fields, potentially leading to observable deviations from a nearly perfect cosmic microwave background black body spectrum: $n$-type spectral distortions, affecting the normalization of the spectral energy density. Finally, we put stringent constraints on $f(R,{\mathcal{L}}_m)$ theories of gravity using the COBE-FIRAS measurement of the spectral radiance of the cosmic microwave background.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2018)·57 citations
24. 24*

    What do the highest-energy cosmic-ray data suggest about possible new physics around 50 TeV?

    Vasiliki Pavlidou🇬🇷 · Theodore Tomaras🇬🇷

    The latest observations of extensive air showers (EAS) induced by ultra-high-energy cosmic rays (UHECR) appear to indicate, prima facie, a transition to heavy primaries at the highest energies. However, this interpretation, which is based on extrapolations of the Standard Model (SM) to ultra-LHC energies, is strained from both astrophysical and particle phenomenology perspectives. We consider the alternative that after some energy threshold, the first collision of the primary in the atmosphere results in a state, the decay of which leads to a considerably increased shower particle multiplicity, so that light-primary EAS appear heavy-like. We show that a minimal implementation of such a model yields predictions for the average EAS depth and shower-to-shower fluctuations that are consistent with each other, and an excellent fit to Auger data. If such an effect indeed takes place, we predict that: (a) the center-of-momentum (CM) energy threshold for the effect is of order 50 TeV; (b) the probability with which the effect occurs is high, and it will be detected easily by next-generation accelerators; (c) the increase in multiplicity compared to the SM prediction grows with CM energy roughly as $\sim E_{\mathrm{CM}}$; (d) the cosmic-ray composition at the highest energies is light. Remarkably, if the latter is confirmed electromagnetically this would necessitate the existence of new physics by these energies.

    ↳ astro-ph.HEhep-phPRD(2019)·9 citations
25. 25*

    Neutron Star Mergers Chirp About Vacuum Energy

    Csaba Csáki🇺🇸 · Cem Eröncel🇺🇸 · Jay Hubisz🇺🇸 · Gabriele Rigo🇺🇸 · John Terning🇺🇸

    Observations of gravitational waves from neutron star mergers open up novel directions for exploring fundamental physics: they offer the first access to the structure of objects with a non-negligible contribution from vacuum energy to their total mass. The presence of such vacuum energy in the inner cores of neutron stars occurs in new QCD phases at large densities, with the vacuum energy appearing in the equation of state for a new phase. This in turn leads to a change in the internal structure of neutron stars and influences their tidal deformabilities which are measurable in the chirp signals of merging neutron stars. By considering three commonly used neutron star models we show that for large chirp masses the effect of vacuum energy on the tidal deformabilities can be sizable. Measurements of this sort have the potential to provide a first test of the gravitational properties of vacuum energy independent from the acceleration of the Universe, and to determine the size of QCD contributions to the vacuum energy.

    ↳ astro-ph.HEhep-phnucl-thJHEP(2018)·28 citations
26. 26*

    Searching for galactic axions through magnetized media: QUAX status report

    G. Ruoso🇮🇹 · D. Alesini🇮🇹 · C. Braggio🇮🇹 · G. Carugno🇮🇹 · N. Crescini🇮🇹 · D. Di Gioacchino🇮🇹 · P. Falferi🇮🇹 · S. Gallo🇮🇹 · U. Gambardella🇮🇹 · C. Gatti🇮🇹 · G. Iannone🇮🇹 · G. Lamanna🇮🇹 and 6 other authors

    The current status of the QUAX R\&D program is presented. QUAX is a feasibility study for a detection of axion as dark matter based on the coupling to the electrons. The relevant signal is a magnetization change of a magnetic material placed inside a resonant microwave cavity and polarized with a static magnetic field.

    ↳ physics.ins-dethep-ph2 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.