Thu·Dec 13, 2018Thursday·December 13, 2018

1. 01*

   Impact of Vacuum Stability Constraints on the Phenomenology of Supersymmetric Models

   Wolfgang G. Hollik🇩🇪 · Georg Weiglein🇩🇪 · Jonas Wittbrodt🇩🇪

   We present a fast and efficient method for studying vacuum stability constraints in multi-scalar theories beyond the Standard Model. This method is designed for a reliable use in large scale parameter scans. The minimization of the scalar potential is done with the well-known polynomial homotopy continuation, and the decay rate of a false vacuum in a multi-scalar theory is estimated by an exact solution of the bounce action in the one-field case. We compare to more precise calculations of the tunnelling path at the tree- and one-loop level and find good agreement for the resulting constraints on the parameter space. Numerical stability, runtime and reliability are significantly improved compared to approaches existing in the literature. This procedure is applied to several phenomenologically interesting benchmark scenarios defined in the Minimal Supersymmetric Standard Model. We utilize our efficient approach to study the impact of simultaneously varying multiple fields and illustrate the importance of correctly identifying the most dangerous minimum among the minima that are deeper than the electroweak vacuum.

   hep-phJHEP(2019)·94 citations
2. 02*

   xSLHA: an Les Houches Accord reader for Python and Mathematica

   Florian Staub🇩🇪

   The format defined by the SUSY Les Houches Accord (SLHA) is widely used in high energy physics to store and exchange information. It is no longer applied only to a few supersymmetric models, but the general structure is adapted to all kind of models. Therefore, it is helpful to have parsers at hand which can import files in the SLHA format into high-level languages as Python and Mathematica in order to further process the data. The focus of the xSLHA package, which exists now for Python and Mathematica, was on a fast read-in of large data samples. Moreover, also some blocks used by different tools, as HiggsBounds for instance, deviate from the standard conventions. These are also supported by xSLHA.

   hep-phhep-exComput.Phys.Commun.(2019)·9 citations
3. 03*

   CP Symmetries as Guiding Posts: Revamping Tri-Bi-Maximal Mixing-I

   Peng Chen🇨🇳 · Salvador Centelles Chuliá🇪🇸 · Gui-Jun Ding🇨🇳 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸

   We analyze the possible generalized CP symmetries admitted by the Tri-Bi-Maximal (TBM) neutrino mixing. Taking advantage of these symmetries we construct in a systematic way other variants of the standard TBM ansatz. Depending on the type and number of generalized CP symmetries imposed, we get new mixing matrices, all of which related to the original TBM matrix. One of such "revamped" TBM variants is the recently discussed mixing matrix of arXiv:1806.03367. We also briefly discuss the phenomenological implications following from these mixing patterns.

   hep-phJHEP(2019)·18 citations
4. 04*

   Testing the standard model with $D_{(s)}\to K_1(\to K\pi \pi )\gamma$ decays

   Nico Adolph🇩🇪 · Gudrun Hiller🇩🇪 · Andrey Tayduganov🇩🇪

   The photon polarization in $D_{(s)}\to K_1(\to K\pi \pi )\gamma$ decays can be extracted from an up-down asymmetry in the $K\pi \pi$ system, along the lines of the method known to $B\to K_1(\to K\pi \pi )\gamma$ decays. Charm physics is advantageous as partner decays exist: $D^{+}\to K_1^{+}(\to K\pi \pi )\gamma$, which is standard model-like, and $D_s\to K_1^{+}(\to K\pi \pi )\gamma$, which is sensitive to physics beyond the standard model in $|\Delta c|=|\Delta u|=1$ transitions. The standard model predicts their photon polarizations to be equal up to U-spin breaking corrections, while new physics in the dipole operators can split them apart at order one level. We estimate the proportionality factor in the asymmetry multiplying the polarization parameter from axial vectors $K_1(1270)$ and $K_1(1400)$ to be sizable, up to the few $\mathcal{O}(10)\%$ range. The actual value of the hadronic factor matters for the experimental sensitivity, but is not needed as an input to perform the null test.

   hep-phhep-exPRD(2019)·20 citations
5. 05*

   Charged Higgs Bosons in Naturally Aligned Two Higgs Doublet Models at the LHC

   Emily Hanson🇬🇧 · William Klemm🇬🇧 · Roger Naranjo🇩🇪 · Yvonne Peters🇬🇧 · Apostolos Pilaftsis🇬🇧

   Measurements of a Higgs boson at the Large Hadron Collider (LHC) have become increasingly consistent with the predictions of the Standard Model (SM). This fact puts severe constraints on many potential low-energy extensions of the Higgs sector of the SM. In the well-known Two Higgs Doublet Model (2HDM), an `alignment limit' of parameters readily furnishes one SM-like scalar, and can be achieved naturally through an underlying symmetry. Among the other physical states of the 2HDM, a charged scalar $H^{\pm }$ would provide striking evidence of new physics if observed. We propose a novel technique for the observation of the process $pp\to tb{H}^{\pm }\to t\bar{t}b\bar{b}$ in the dileptonic decay channel at the LHC. The reconstruction of events in this channel is complicated by multiple $b$-jets and unobserved neutrinos in the final state. To determine the neutrino momenta, we implement a neutrino weighting procedure to study, for the first time, the $t\bar{t}b\bar{b}$ signature. We further train a pair of boosted decision trees to reconstruct and classify signal events. We determine the resulting reach within the context of naturally aligned 2HDMs, such as the Maximally Symmetric Two Higgs Doublet Model (MS-2HDM). By testing at the integrated luminosity of 150 fb${}^{-1}$ achieved in Run 2 of the LHC, we find that this channel may restrict the parameter space of a Type-II MS-2HDM with charged Higgs masses as high as 680 GeV.

   hep-phhep-exPRD(2019)·8 citations
6. 06*

   Transverse momentum $p_{\mathrm{T}}$ spectra of strange particles production in different collisions at $\sqrt{s_{NN}}=2.76,5.02,$ and $7$ TeV

   Hayam Yassin🇪🇬 · Eman R. Abo Elyazeed🇪🇬

   We analyse the transverse momentum $p_{\mathrm{T}}$ spectra of strange particles \Kslxi produced in $\text{Pb+Pb}$ collision at $\sqrt{s_{NN}}=2.76$ TeV, $\text{p+Pb}$ collision at $\sqrt{s_{NN}}=5.02$ TeV, and $\text{p+p}$ collision at $\sqrt{s_{NN}}=7$ TeV in different multiplicity events measured by the \textit{CMS} experiment at the Large Hadron Collider. The $p_{\mathrm{T}}$ spectra of strange particles are fitted by Tsallis statistics and Boltzmann statistics, respectively. The fitting parameters are studied as a function of the multiplicity events for all systems. The Tsallis temperature ($T_{\mathtt{Ts}}$), Boltzmann temperature ($T_{\mathtt{Boltz}}$), and radius of the system ($R$) increase with both the mass and strangeness number of the particle and also increase with the multiplicity events. The non-extensive parameter ($q$) decreases with the increase in the mass of the particle and also decrease with the increase in the multiplicity events which means that the system tends to thermodynamic stabilization. The extracted temperatures from the two statistics for the strange particles are exhibited a linear correlation.

   hep-phnucl-thAPhysPol B 50, 37 (2019)·2 citations
7. 07*

   Charmed baryons in nuclear matter

   T. F. Caramés🇪🇸 · C. E. Fontoura🇧🇷 · G. Krein🇧🇷 · J. Vijande🇪🇸 · A. Valcarce🇪🇸

   We study the temperature and baryon density dependence of the masses of the lightest charmed baryons ${\Lambda }_c$, ${\Sigma }_c$ and ${\Sigma }_c^{\ast }$. We also look at the effects of the temperature and baryon density on the binding energies of the ${\Lambda }_{c}N$ and ${\Lambda }_c{\Lambda }_c$ systems. Baryon masses and baryon-baryon interactions are evaluated within a chiral constituent quark model. Medium effects are incorporated in those parameters of the model related to the dynamical breaking of chiral symmetry, which are the masses of the constituent quarks, the $\sigma$ and $\pi$ meson masses, and quark-meson couplings. We find that while the in-medium ${\Lambda }_c$ mass decreases monotonically with temperature, those of ${\Sigma }_c$ and ${\Sigma }_c^{\ast }$ have a nonmonotonic dependence. These features can be understood in terms of a simple group theory analysis regarding the one-gluon exchange interaction in those hadrons. The in-medium ${\Lambda }_{c}N$ and ${\Lambda }_c{\Lambda }_c$ interactions are governed by a delicate balance involving a stronger attraction due to the decrease of the $\sigma$ meson mass, suppression of coupled-channel effects and lower thresholds, leading to shallow bound states with binding energies of a few~MeV. The ${\Lambda }_c$ baryon could possibly be bound to a large nucleus, in qualitative agreement with results based on relativistic mean field models or QCD sum rules. Ongoing experiments at RHIC or LHCb or the planned ones at FAIR and J-PARC may take advantage of the present results.

   hep-phhep-latnucl-thPRD(2018)·10 citations
8. 08*

   A complete asymptotically safe embedding of the Standard Model

   Steven Abel🇬🇧 · Esben Molgaard🇩🇰 · Francesco Sannino🇩🇰

   We present and discuss the "Tetrad Model", a large colour/flavour embedding of the Standard model which has an interacting ultraviolet fixed point. It is shown that its extended-Pati-Salam symmetry is broken radiatively via the Coleman-Weinberg mechanism, while the remaining electroweak symmetry is broken when mass-squared terms run negative. In the IR the theory yields just the Standard Model, augmented by the fact that the Higgs fields carry the same generation indices as the matter fields. It is also shown that the Higgs mass-squareds develop a hierarchical structure in the IR, from a UV theory that is asymptotically flavour symmetric, opening up an interesting direction for explaining the emergence of the observed flavour structure.

   hep-phPRD(2019)·21 citations
9. 09*

   Spectroscopy of light $N^{\ast }$ baryons

   Zalak Shah🇮🇳 · Keval Gandhi🇮🇳 · Ajay Kumar Rai🇮🇳

   We present the masses of N baryon upto 3300 MeV. The radial and orbital excited states are determined using hypercentral constituent quark model with first order correction. The obtained masses are compared with experimental results and other theoretical prediction. The Regge Trajectories are also determined in (n, $M^2$) and (J, $M^2$) planes. Moreover, the magnetic moments for $J^P={\frac{1}{2}}^{+},{\frac{1}{2}}^{-}$ are calculated. We also calculate the $N\pi$ decay width of excited nucleons.

   hep-phnucl-thCPC(2019)·34 citations
10. 10*

    LHC Searches for Dark Matter in Compressed Mass Scenarios: Challenges in the Forward Proton Mode

    L.A. Harland-Lang🇬🇧 · V.A. Khoze🇬🇧 · M.G. Ryskin🇷🇺 · M. Tasevsky🇨🇿

    We analyze in detail the LHC prospects at the center-of-mass enery of 14 TeV for charged electroweakino searches, decaying to leptons, in compressed supersymmetry scenarios, via exclusive photon-initiated pair production. This provides a potentially increased sensitivity in comparison to inclusive channels, where the background is often overwhelming. We pay particular attention to the challenges that such searches would face in the hostile high pile--up environment of the LHC, giving close consideration to the backgrounds that will be present. The signal we focus on is the exclusive production of same-flavour muon and electron pairs, with missing energy in the final state, and with two outgoing intact protons registered by the dedicated forward proton detectors installed in association with ATLAS and CMS. We present results for slepton masses of 120--300 GeV and slepton--neutralino mass splitting of 10--20 GeV, and find that the relevant backgrounds can be controlled to the level of the expected signal yields. The most significant such backgrounds are due to semi--exclusive lepton pair production at lower masses, with a proton produced in the initial proton dissociation system registering in the forward detectors, and from the coincidence of forward protons produced in pile-up events with an inclusive central event that mimics the signal. We also outline a range of potential methods to further suppress these backgrounds as well as to enlarge the signal yields.

    hep-phJHEP(2019)·58 citations
11. 11*

    Identified particle production in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV using a multiphase transport model

    Rutuparna Rath🇮🇳 · Sushanta Tripathy🇮🇳 · Raghunath Sahoo🇮🇳 · Sudipan De🇮🇳 · Mohammed Younus🇿🇦

    Xe+Xe collisions at relativistic energies provide us with an opportunity to study a possible system with deconfined quarks and gluons, whose size is in between those produced by p+p and Pb+Pb collisions. In the present work, we have used AMPT transport model with nuclear deformation to study the identified particle production such as (${\pi }^{+}+{\pi }^{-}$), (K${}^{+}$+K${}^{-}$), ${\mathrm{K}}_{\mathrm{s}}^0$, (p+$\bar{\mathrm{p}}$), $\varphi$ and ($\Lambda +\bar{\Lambda }$) in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}$=5.44 TeV. We study the $p{}_{\mathrm{T}}$-spectra, integrated yield, $p{}_{\mathrm{T}}$-differential and $p{}_{\mathrm{T}}$-integrated particle ratios to (${\pi }^{+}+{\pi }^{-}$) and (K${}^{+}$+K${}^{-}$) as a function of collision centrality. The particle ratios are focused on strange to non-strange ratios and baryon to meson ratios. The effect of deformations has also been highlighted by comparing our results to non-deformation case. We have also compared the results from AMPT string melting and AMPT default version to explore possible effects of coalescence mechanism. We observe that the differential particle ratios show strong dependence with centrality while the integrated particle ratios show no centrality dependence.We give thermal model estimation of chemical freeze-out temperature and the Boltzmann-Gibbs Blast Wave analysis of kinetic freeze-out temperature and collective radial flow in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV.

    hep-phhep-exnucl-exnucl-thPRC(2019)·10 citations
12. 12*

    One-loop structure of the photon propagator in the Standard Model Extension

    A. I. Hernández-Juárez🇲🇽 · J. Montaño🇲🇽 · H. Novales-Sánchez🇲🇽 · M. Salinas🇲🇽 · J. J. Toscano🇲🇽 · O. Vázquez-Hernández🇲🇽

    We study radiative corrections on the photon propagator from the electroweak sector of the minimal Lorentz- and $CPT$-violating Standard Model Extension. We derive the most general Lorentz-violating ghost sector from BRST symmetry and renormalization theory. We introduce a Lorentz-violating nonlinear gauge that simplifies both the Higgs and gauge-sector extensions, which can be helpful in radiative corrections. At one loop, these sectors contribute to the $CPT$-even part of the photon propagator, characterized by the Riemann-type tensor $(k_F{)}_{\alpha \beta \mu \nu }$. We give exact results for the contributions to the SO(1,3) irreducible parts of $(k_F{)}_{\alpha \beta \mu \nu }$, namely, the Weyl-type tensor $({\hat{k}}_F{)}_{\alpha \beta \mu \nu }$, the Ricci-type tensor $(k_F{)}_{\alpha \beta }$, and the curvature-type scalar $k_F$. In the Yukawa sector, one-loop contributions are ultraviolet finite, but most of them are unobservable due to finite renormalization. The only observable effect is a contribution proportional to $(k_F{)}_{\alpha \beta }$ that emerges via a dimension-6 term that is observer and gauge invariant. In the Higgs and gauge sectors, all the irreducible parts of the corresponding Riemann-type tensors receive divergent contributions, so they are observable. The only finite contribution corresponds to the dimension-6 term. We think of these contributions as radiative corrections to the renormalized tensors and assume that both effects are of the same order of magnitude to find bounds from vacuum birefringence and compare with the literature. Bounds on $(k_F{)}_{\alpha \beta }$ contributions, innocuous to birefringence, are also derived using limits on the renormalized tensor from Laser-Interferometer-Gravitational-Wave-Observatory data. We compare these bounds with the literature. Beta functions associated with $({\hat{k}}_F{)}_{\alpha \beta \mu \nu }$ and $(k_F{)}_{\alpha \beta }$ are derived.

    hep-phPRD(2019)·11 citations
13. 13*

    Elements of QED-NRQED Effective Field Theory: II. Matching of Contact Interactions

    Steven P. Dye🇺🇸 · Matthew Gonderinger🇺🇸 · Gil Paz🇺🇸

    In 2010 the first extraction of the proton charge radius from muonic hydrogen was found be be five standard deviations away form the regular hydrogen value. Eight years later, this proton radius puzzle is still unresolved. One of the most promising avenues to resolve the puzzle is by a muon-proton scattering experiment called MUSE. The typical momenta of the muons in this experiment are of the order of the muon mass. In this energy regime the muons are relativistic but the protons are non-relativistic. The interaction between them can be described by QED-NRQED effective field theory. In a previous paper we have shown how QED-NRQED reproduces Rosenbluth scattering up to $1/M^2$, where $M$ is the proton mass, and relativistic scattering off a static potential at $\mathcal{O}(Z^2{\alpha }^2)$ and leading power in $M$. In this paper we determine the Wilson coefficients of the four-fermion contact interactions at $\mathcal{O}(Z^2{\alpha }^2)$ and power $1/M^2$. Surprisingly, we find that the coefficient of the spin-independent interaction vanishes, implying that MUSE will be sensitive mostly to the proton charge radius and not spin-independent two-photon exchange effects.

    hep-phPRD(2019)·11 citations
14. 14*

    Minimal $Z^{\prime }$ models for flavor anomalies

    Richard H. Benavides🇨🇴 · Luis Muñoz🇨🇴 · William A. Ponce🇨🇴 · Oscar Rodríguez🇨🇴 · Eduardo Rojas🇨🇴

    By allowing gauge anomaly cancellation between fermions in different families we find a non-universal solution for a $Z^{\prime }$ family of models with the same content of fermions of the standard model plus three right-handed neutrinos. We also impose constraints from the Yukawa interaction terms in such a way that at the end we obtain a solution with six free parameters. Our solution contains as particular cases well-known models in the literature. As an application, we report a model that evades LHC constraints, flavor changing neutral currents and low energy constraints. Simultaneously, the model is able to explain the flavor anomalies in the Wilson coefficients $C_9(\mu )$ and $C_{10}(\mu )$ without modifying the corresponding Wilson coefficients for the first family. In our approach, this procedure is always possible for $Z^{\prime }$ masses smaller than $\sim 2.5$~TeV.

    hep-phJ.Phys.G(2020)·11 citations
15. 15*

    Monochromatic dark neutrinos and boosted dark matter in noble liquid direct detection

    David McKeen🇨🇦 · Nirmal Raj🇨🇦

    If dark matter self-annihilates into neutrinos or a second component of ("boosted") dark matter that is nucleophilic, the annihilation products may be detected with high rates via coherent nuclear scattering. A future multi-ten-tonne liquid xenon detector such as DARWIN, and a multi-hundred-tonne liquid argon detector, ARGO, would be sensitive to the flux of these particles in complementary ranges of $10-1000$ MeV dark matter masses. We derive these sensitivities after accounting for atmospheric and diffuse supernova neutrino backgrounds, and realistic nuclear recoil acceptances. We find that their constraints on the dark neutrino flux may surpass neutrino detectors such as Super-Kamiokande, and that they would extensively probe parametric regions that explain the missing satellites problem in neutrino portal models. The XENON1T and Borexino experiments currently restrict the effective baryonic coupling of thermal boosted dark matter to $\lesssim 10-100\times$ the weak interaction, but DARWIN and ARGO would probe down to couplings 10 times smaller. Detection of boosted dark matter with baryonic couplings $\sim 10^{-3}-10^{-2}\times$ the weak coupling could indicate that the dark matter density profile in the centers of galactic halos become cored, rather than cuspy, through annihilations. This work demonstrates that, alongside liquid xenon, liquid argon direct detection technology would emerge a major player in dark matter searches within and beyond the WIMP paradigm.

    hep-phastro-ph.HEhep-exPRD(2019)·53 citations
16. 16*

    Probing Light Dark Matter with a Hadrophilic Scalar Mediator

    Brian Batell🇺🇸 · Ayres Freitas🇺🇸 · Ahmed Ismail🇺🇸 · David McKeen🇨🇦

    We investigate the thermal cosmology and terrestrial and astrophysical phenomenology of a sub-GeV hadrophilic dark sector. The specific construction explored in this work features a Dirac fermion dark matter candidate interacting with a light scalar mediator that dominantly couples to the up-quark. The correct freeze-out relic abundance may be achieved via dark matter annihilation directly to hadrons or through secluded annihilation to scalar mediators. A rich and distinctive phenomenology is present in this scenario, with probes arising from precision meson decays, proton beam dump experiments, colliders, direct detection experiments, supernovae, and nucleosynthesis. In the future, experiments such as NA62, REDTOP, SHiP, SBND, and NEWS-G will be able to explore a significant portion of the cosmologically motivated parameter space.

    hep-phhep-exPRD(2019)·104 citations
17. 17*

    Sorting out quenched jets

    Jasmine Brewer🇺🇸 · José Guilherme Milhano🇵🇹 · Jesse Thaler🇺🇸

    We introduce a new 'quantile' analysis strategy to study the modification of jets as they traverse through a droplet of quark-gluon plasma. To date, most jet modification studies have been based on comparing the jet properties measured in heavy-ion collisions to a proton-proton baseline at the same reconstructed jet transverse momentum ($p_T$). It is well known, however, that the quenching of jets from their interaction with the medium leads to a migration of jets from higher to lower $p_T$, making it challenging to directly infer the degree and mechanism of jet energy loss. Our proposed quantile matching procedure is inspired by (but not reliant on) the approximate monotonicity of energy loss in the jet $p_T$. In this strategy, jets in heavy-ion collisions ordered by $p_T$ are viewed as modified versions of the same number of highest-energy jets in proton-proton collisions, and the fractional energy loss as a function of jet $p_T$ is a natural observable ($Q_{\mathrm{AA}}$). Furthermore, despite non-monotonic fluctuations in the energy loss, we use an event generator to validate the strong correlation between the $p_T$ of the parton that initiates a heavy-ion jet and the $p_T$ of the vacuum jet which corresponds to it via the quantile procedure ($p_T^{\mathrm{quant}}$). We demonstrate that this strategy both provides a complementary way to study jet modification and mitigates the effect of $p_T$ migration in heavy-ion collisions.

    hep-phhep-exnucl-exnucl-thPRL(2019)·50 citations
18. 18*

    Parton-shower effects in electroweak $WZjj$ production at the next-to-leading order of QCD

    Barbara Jager🇩🇪 · Alexander Karlberg🇨🇭 · Johannes Scheller🇩🇪

    We present an implementation of $WZjj$ production via vector-boson fusion in the POWHEG BOX, a public tool for the matching of next-to-leading order QCD calculations with multi-purpose parton-shower generators. We provide phenomenological results for electroweak $WZjj$ production with fully leptonic decays at the LHC in realistic setups and discuss theoretical uncertainties associated with the simulation. We find that beyond the leading-order approximation the dependence on the unphysical factorization and renormalization scales is mild. The two tagging jets are furthermore very stable against parton-shower effects. However, considerable sensitivities to the shower Monte-Carlo program used are observed for central-jet veto observables.

    hep-phhep-exEPJC(2019)·28 citations
19. 19*

    Polarisabilities from Compton Scattering on 3He

    Harald W. Griesshammer (George Washington U.)🇺🇸 · Judith A. McGovern (U. of Manchester)🇬🇧

    This executive summary of recent theory progress in Compton scattering off 3He focuses on determining neutron polarisabilities; see ref. [2] and references therein for details and a better bibliography. Prepared for the Proceedings of the 22nd International Conference on Few-Body Problems in Physics, Caen 9-13 July 2018.

    ↳ nucl-thhep-ph1 citation
20. 20*

    First determination of the $\rho$ parameter at $\sqrt{s}=13$ TeV -- probing the existence of a colourless three-gluon bound state

    TOTEM Collaboration: G. Antchev🇨🇭 · P. Aspell🇨🇭 · I. Atanassov🇵🇱 · V. Avati🇵🇱 · J. Baechler🇨🇭 · C. Baldenegro Barrera🇺🇸 · V. Berardi🇮🇹 · M. Berretti🇫🇮 · E. Bossini🇮🇹 · U. Bottigli🇮🇹 · M. Bozzo🇮🇹 · R. Bruce🇨🇭 and 83 other authors

    The TOTEM experiment at the LHC has performed the first measurement at $\sqrt{s}=13$ TeV of the $\rho$ parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at $t=0$, obtaining the following results: $\rho =0.09\pm 0.01$ and $\rho =0.10\pm 0.01$, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the $\rho$ measurement, combined with the TOTEM total cross-section measurements in an energy range larger than 10 TeV (from 2.76 to 13 TeV), has implied the exclusion of all the models classified and published by COMPETE. The $\rho$ results obtained by TOTEM are compatible with the predictions, from alternative theoretical models both in the Regge-like framework and in the QCD framework, of a colourless 3-gluon bound state exchange in the $t$-channel of the proton-proton elastic scattering. On the contrary, if shown that the 3-gluon bound state $t$-channel exchange is not of importance for the description of elastic scattering, the $\rho$ value determined by TOTEM would represent a first evidence of a slowing down of the total cross-section growth at higher energies. The very low-$|t|$ reach allowed also to determine the absolute normalisation using the Coulomb amplitude for the first time at the LHC and obtain a new total proton-proton cross-section measurement ${\sigma }_{tot}=110.3\pm 3.5$ mb, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields ${\sigma }_{tot}=110.5\pm 2.4$ mb.

    ↳ hep-exhep-phnucl-exEPJC(2019)·247 citations
21. 21*

    Early formation of supermassive black holes via dark matter self-interactions

    Jeremie Choquette🇨🇦 · James M. Cline🇨🇦 · Jonathan M. Cornell🇺🇸

    The existence of supermassive black holes at high redshifts ($z\sim 7$) is difficult to accommodate in standard astrophysical scenarios. It has been shown that dark matter models with a subdominant self-interacting component are able to produce early seeds for supermassive black holes through the gravothermal catastrophe. Previous studies used a fluid equation approach, requiring some limiting assumptions. Here we reconsider the problem using $N$-body gravitational simulations starting from the formation of the initial dark matter halo. We consider both elastic and dissipative scattering, and elucidate the interplay between the dark matter microphysics and subsequent accretion of the black hole needed to match the properties of observed high redshift supermassive black holes. We find a region of parameter space in which a small component of self-interacting dark matter can produce the observed high redshift supermassive black holes.

    ↳ astro-ph.COastro-ph.GAhep-phJCAP(2019)·76 citations
22. 22*

    Probing the Fermi-LAT GeV excess with gravitational waves

    Francesca Calore🇫🇷 · Tania Regimbau🇫🇷 · Pasquale Dario Serpico🇫🇷

    If the gamma-ray excess towards the inner Galaxy (GCE) detected in Fermi-LAT data is due to millisecond pulsars (MSPs), one expects an associated gravitational wave (GW) signal, whose intensity exceeds the disk MSP population emission by an order of magnitude. We compute the expected GW counterpart of the bulge MSP population based on fits of the GCE, and estimate the sensitivity reach of current and future terrestrial GW detectors. The bounds on the average population ellipticity $\epsilon$ are competitive with the existing ones derived by LIGO/Virgo towards known MSPs. With a 10-year data taking in current LIGO/Virgo configuration, one would detect a signal at the level $\epsilon \simeq 10^{-7}$, while $\epsilon \simeq 10^{-8}$ would be attainable with a similar data taking period with a third generation GW detector. This sensitivity should be sufficient for crucial diagnostics on the GCE interpretation in terms of MSPs.

    ↳ astro-ph.HEgr-qchep-phPRL(2019)·18 citations
23. 23*

    Distribution Amplitudes of Heavy-Light Mesons

    Daniele Binosi🇮🇹 · Lei Chang🇨🇳 · Minghui Ding🇮🇹 · Fei Gao🇪🇸 · Joannis Papavassiliou🇪🇸 · Craig D. Roberts🇺🇸

    A symmetry-preserving approach to the continuum bound-state problem in quantum field theory is used to calculate the masses, leptonic decay constants and light-front distribution amplitudes of empirically accessible heavy-light mesons. The inverse moment of the $B$-meson distribution is particularly important in treatments of exclusive $B$-decays using effective field theory and the factorisation formalism; and its value is therefore computed: ${\lambda }_B(\zeta =2\mathrm{GeV})=0.54(3)$GeV. As an example and in anticipation of precision measurements at new-generation $B$-factories, the branching fraction for the rare $B\to \gamma (E_{\gamma })\ell {\nu }_{\ell }$ radiative decay is also calculated, retaining $1/m_B^2$ and $1/E_{\gamma }^2$ corrections to the differential decay width, with the result ${\Gamma }_{B\to \gamma \ell {\nu }_{\ell }}/{\Gamma }_B=0.47(15)$ on $E_{\gamma }>1.5$GeV.

    ↳ nucl-thhep-lathep-phPLB(2019)·52 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.