Thu·Apr 25, 2019Thursday·April 25, 2019

1. 01*

   Neutrino Splitting for Lorentz-Violating Neutrinos: Detailed Analysis

   G. Somogyi🇭🇺 · I. Nandori🇭🇺 · U. D. Jentschura🇺🇸

   Lorentz-violating neutrino parameters have been severely constrained on the basis of astrophysical considerations. In the high-energy limit, one generally assumes a superluminal dispersion relation of an incoming neutrino of the form E ~ |p|v, where E is the energy, p is the momentum and $v = sqrt(1 + delta) > 1. Lepton-pair creation due to a Cerenkov-radiation-like process (nu -> nu + e^- + e^+) becomes possible above a certain energy threshold, and bounds on the Lorentz-violating parameter delta can be derived. Here, we investigate a related process, nu_i -> nu_i + nu_f + bar_nu_f, where nu_i is an incoming neutrino mass eigenstate, while nu_f is the final neutrino mass eigenstate, with a superluminal velocity that is slightly slower than that of the initial state. This process is kinematically allowed if the Lorentz-violating parameters at high energy differ for the different neutrino mass eigenstates. Neutrino splitting is not subject to any significant energy threshold condition and could yield quite a substantial contribution to decay and energy loss processes at high energy, even if the differential Lorentz violation among neutrino flavors is severely constrained by other experiments. We also discuss the SU(2)-gauge invariance of the superluminal models and briefly discuss the use of a generalized vierbein formalism in the formulation of the Lorentz-violating Dirac equation.

   hep-phhep-thPRD(2019)·12 citations
2. 02*

   Baryogenesis via Gravitational Spontaneous Symmetry Breaking

   Qiuyue Liang🇺🇸 · Jeremy Sakstein🇺🇸 · Mark Trodden🇺🇸

   We study baryogenesis in effective field theories where a $\mathrm{U}(1{)}_{B-L}$-charged scalar couples to gravity via curvature invariants. We analyze the general possibilities in such models, noting the relationships between some of them and existing models, such as Affleck-Dine baryogenesis. We then identify a novel mechanism in which $\mathrm{U}(1{)}_{B-L}$ can be broken by couplings to the Gauss-Bonnet invariant during inflation and reheating. Using analytic methods, we demonstrate that this mechanism provides a new way to dynamically generate the net matter-anti-matter asymmetry observed today, and verify this numerically.

   hep-phgr-qchep-thPRD(2019)·12 citations
3. 03*

   Comment on "Search for an axion-induced oscillating electric dipole moment for electrons using atomic magnetometers"

   P.-H. Chu🇺🇸 · Y. J. Kim🇺🇸 · I. Savukov🇺🇸

   In the recent work arXiv:1809.02446, the authors proposed a new method measuring the electron oscillating electric dipole moment (eOEDM) using atomic magnetomaters. This eOEDM is induced by the interaction between the electron magnetic dipole moment, electric field and axion field. The result is sensitive to the axion-photon coupling according to [Hill, PRD 91, 111702 (2015)]. Here we want to describe that the same experimental method can be also sensitive to the axion-electron coupling according to [Alexander and Sims, PRD 98, 015011 (2018)]. In this article, we will show the corresponding sensitivity plot and compare with other constraints.

   hep-phnucl-ex5 citations
4. 04*

   Leptogenesis in $\Delta (27)$ with a Universal Texture Zero

   Fredrik Björkeroth🇮🇹 · Ivo de Medeiros Varzielas🇵🇹 · M.L. López-Ibáñez🇪🇸 · Aurora Melis🇪🇸 · Óscar Vives🇪🇸

   We investigate the possibility of viable leptogenesis in an appealing $\Delta (27)$ model with a universal texture zero in the (1,1) entry. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both $N_1$ and $N_2$ right-handed neutrino decays. The $N_1$-dominated scenario is successful and the most natural option for the model, with $M_1\in [10^9,10^{12}]$ GeV, and $M_1/M_2\in [0.002,0.1]$, which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the $N_2$-dominated scenario, with the asymmetry in the electron flavour protected from $N_1$ washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy $M_1/M_2<0.002$, and $M_2$ relatively close to $M_3$, which is not a natural expectation of the $\Delta (27)$ model.

   hep-phJHEP(2019)·14 citations
5. 05*

   Rate of dark photon emission from electron positron annihilation in massive stars

   Ermal Rrapaj🇺🇸 · Andre Sieverding🇺🇸 · Yong-Zhong Qian🇺🇸

   We calculate the rate of production of dark photons from electron-positron pair annihilation in hot and dense matter characteristic of supernova progenitors. Given the non-linear dependence of the emission rate on the dark photon mass and current astrophysical constraints on the dark photon parameter space, we focus on the mass range of 1--10 MeV. For the conditions under consideration both mixing with the in-medium photon and plasma effects on the electron dispersion relation are non-negligible and are explored in detail. We perform our calculations to the leading order in the fine-structure constant. Transverse and longitudinal photon modes are treated separately given their different dispersion relations. We consider the implications for the evolution of massive stars when dark photons decay either into particles of the standard model or of the dark sector.

   hep-phastro-ph.SRPRD(2019)·7 citations
6. 06*

   Classical neutral point particle in linearly polarized EM plane wave field

   Martin Formanek🇺🇸 · Andrew Steinmetz🇺🇸 · Johann Rafelski🇺🇸

   We study a covariant classical model of neutral point particles with magnetic moment interacting with external electromagnetic fields. Classical dynamical equations which reproduce a correct behavior in the non-relativistic limit are introduced. We also discuss the non-uniqueness of the covariant torque equation. The focus of this work is on Dirac neutrino beam control. We present a full analytical solution of the dynamical equations for a neutral point particle motion in the presence of an external linearly polarized EM plane wave (laser) fields. Neutrino beam control using extremely intense laser fields could possibly demonstrate Dirac nature of the neutrino. However, for linearly polarized ideal laser waves we show cancellation of all leading beam control effects.

   hep-phPlasma Phys.Control.Fusion(2019)·4 citations
7. 07*

   Matrix norms and search for sterile neutrinos

   Wojciech Flieger🇵🇱 · Franciszek Pindel🇵🇱 · Kamil Porwit🇵🇱

   Matrix norms can be used to measure the "distance" between two matrices which translates naturally to the problem of calculating the unitary deviation of the neutrino mixing matrices. Variety of matrix norms opens a possibility to measure such deviations on different structural levels of the mixing matrix.

   hep-phPoS(2019)·2 citations
8. 08*

   Searching for axionlike particle at future $ep$ colliders

   Chong-Xing Yue🇨🇳 · Ming-Ze Liu🇨🇳 · Yu-Chen Guo🇨🇳

   We explore the possibility of searching for axionlike particle (ALP) by $ep$ collisions via the subprocess $e^{-}\gamma \to e^{-}a\to e^{-}\gamma \gamma$. Sensitivities to the effective ALP-photon coupling $g_{a\gamma \gamma }$ for its mass in the range of 10 GeV $<M_a<3$ TeV are obtained for the LHeC and its high-energy upgrade, FCC-eh. Comparing to existing bounds on the ALP free parameters, we find that the bounds given by $ep$ colliders are competitive and complementary to other colliders.

   hep-phPRD(2019)·31 citations
9. 09*

   Long-lived light neutralinos at future $Z-$factories

   Zeren Simon Wang🇩🇪 · Kechen Wang🇨🇳

   Future lepton colliders such as the CEPC and FCC-ee would run as high-luminosity $Z-$boson factories, which offer a unique opportunity to study long-lived particles which couple to Z-bosons. In order to exemplify this particular advantage, in this work we consider one benchmark physics scenario where the long-lived lightest neutralinos pair $({\tilde{\chi }}_1^0{\tilde{\chi }}_1^0)$ is produced from $Z-$decays in the context of the R-parity violating supersymmetry. Our analysis indicates that when assuming BR$(Z\to {\tilde{\chi }}_1^0{\tilde{\chi }}_1^0)=10^{-3}$ and $m_{{\tilde{\chi }}_1^0}\sim 40$ GeV, the model parameter ${\lambda }_{112}^{\prime }/m_{\tilde{f}}^2$ can be discovered down to as low as $\sim 1.5\times 10^{-14}$ ($3.9\times 10^{-14}$) GeV${}^{-2}$ at the FCC-ee (CEPC) with center-of-mass energy $\sqrt{s}=91.2$ GeV and 150 (16) ab${}^{-1}$ integrated luminosity. These limits exceed the projected sensitivity reaches of the ATLAS experiment at the HL-LHC and the proposed LHC experiments with far detectors (AL3X, CODEX-b, FASER, and MATHUSLA).

   hep-phPRD(2020)·33 citations
10. 10*

    Phenomenology of keV scale sterile neutrino dark matter with $S_4$ flavor symmetry

    Nayana Gautam🇮🇳 · Mrinal Kumar Das🇮🇳

    We study the possibility of simultaneously addressing neutrino phenomenology and the dark matter in the framework of inverse seesaw. The model is the extension of the standard model by the addition of two right handed neutrinos and three sterile fermions which leads to a light sterile state with the mass in the keV range along with three light active neutrino states. The lightest sterile neutrino can account for a feasible dark matter(DM) candidate. We present a $S_4$ flavor symmetric model which is further augmented by $Z_4\times Z_3$ symmetry to constrain the Yukawa Lagrangian. The structures of the mass matrices involved in inverse seesaw within the $S_4$ framework naturally give rise to correct neutrino mass matrix with non-zero reactor mixing angle ${\theta }_{13}$. In this framework, we conduct a detailed numerical analysis both for normal hierarchy as well as inverted hierarchy to obtain dark matter mass and DM-active mixing which are the key factors for considering sterile neutrino as a viable dark matter candidate. We constrain the parameter space of the model from the latest cosmological bounds on the mass of the dark matter and DM-active mixing.

    hep-phJHEP(2020)·18 citations
11. 11*

    Exploring a ${\Sigma }_c\bar{D}$ state: with focus on $P_c(4312{)}^{+}$

    Jian-Rong Zhang🇨🇳

    Stimulated by the new discovery of $P_c(4312{)}^{+}$ by LHCb Collaboration, we endeavor to perform the study of $P_c(4312{)}^{+}$ as a ${\Sigma }_c\bar{D}$ state in the framework of QCD sum rules. Taking into account the results from two sum rules, a conservative mass range $4.07\sim 4.97\text{mbox}GeV$ is presented for the ${\Sigma }_c\bar{D}$ hadronic system, which agrees with the experimental data of $P_c(4312{)}^{+}$ and could support its interpretation as a ${\Sigma }_c\bar{D}$ state.

    hep-phhep-exEPJC(2019)·58 citations
12. 12*

    Gluons and sea quarks in the proton at low scales

    Markus Diehl🇩🇪 · Pascal Stienemeier🇩🇪

    We study the evolution of parton distributions down to low scales by considering several of their Mellin moments. For the initial conditions, we use a broad array of current parton density fits. Confirming earlier findings in the literature, we conclude that current determinations of parton distributions are incompatible with the idea that gluon or antiquark densities are generated by purely perturbative radiation as it is encoded in the DGLAP evolution equations.

    hep-phEur.Phys.J.Plus(2020)·11 citations
13. 13*

    Constraining CP-violating electron-gluonic operators

    Kingman Cheung🇹🇼 · Wai-Yee Keung🇺🇸 · Ying-nan Mao🇹🇼 · Chen Zhang🇹🇼

    We present an analysis of constraints on two types of CP-odd electron-gluonic operators $(\bar{e}i{\gamma }^{5}e)G_{\mu \nu }^a{G}^{a\mu \nu }$ and $(\bar{e}e)G_{\mu \nu }^a{\tilde{G}}^{a\mu \nu }$ from current and future electric dipole moment (EDM) experiments. The recent result from the ACME experiment using ThO molecules is used to derive an impressive lower bound on the effective scale for $(\bar{e}i{\gamma }^{5}e)G_{\mu \nu }^a{G}^{a\mu \nu }$ at 8 TeV, assuming a QCD one-loop factor and no helicity suppression from new physics. One interesting aspect is that $(\bar{e}i{\gamma }^{5}e)G_{\mu \nu }^a{G}^{a\mu \nu }$ contributes to the observable EDM in ThO experiment mainly through CP-odd electron-nucleon interaction rather than direct electron EDM which arises from three-loop running and matching. For $(\bar{e}e)G_{\mu \nu }^a{\tilde{G}}^{a\mu \nu }$ the current bound is much weaker and suffers from large uncertainties. We also discuss the QCD running and matching for the CP-odd electron-gluonic operators and give an estimate of the relevant nucleon matrix elements and uncertainties that are needed in the calculation.

    hep-phJHEP(2019)·8 citations
14. 14*

    Saturation momentum scale extracted from semi-inclusive transverse spectra in high-energy pp collisions

    Takeshi Osada🇯🇵 · Takuya Kumaoka🇯🇵

    Geometric scaling is well confirmed for transverse momentum distributions observed in proton-proton collisions at LHC energies. We introduced multiplicity dependence on a saturation momentum of the geometrical scaling, assuming the scaling holds for semi-inclusive distributions as well as for inclusive distributions. The saturation momentum is usually given by Bjorken's $x$ variable, but redefinition of the scaling variable can make the saturation momentum a function of collision energy $W$. We treat the energy as a free parameter (denoted $W^{\ast }$ to distinguish it from $W$) and associate the energy-dependent saturation momentum $Q_{\mathrm{sat}}(W^{\ast })$ with particle number density. By using $Q_{\mathrm{sat}}(W^{\ast })$ for a scaling variable $\tau$, we show semi-inclusive distributions can be geometrically scaled. i.e., all semi-inclusive spectra observed at $W$=0.90, 2.76 and 7.00 TeV overlap one universal function. The particle density dependences of mean transverse momentum $⟨p_{\mathrm{T}}⟩$ for LHC energies scales in terms of $Q_{\mathrm{sat}}(W^{\ast })$. Furthermore, our model explains a scaling property of event-by-event $p_{\mathrm{T}}$ fluctuation measure $\sqrt{C_m}/⟨p_{\mathrm{T}}⟩$ at LHC energies for pp collisions, where $C_m$ is two-particle transverse momentum correlator. Our analysis of the $p_{\mathrm{T}}$ fluctuation makes possible to evaluate a non-perturbative coefficient of the gluon correlation function.

    hep-phnucl-thPRC(2019)·12 citations
15. 15*

    Master Integrals for the two-loop, non-planar QCD corrections to top-quark pair production in the quark-annihilation channel

    Matteo Becchetti🇧🇪 · Roberto Bonciani🇮🇹 · Valerio Casconi🇮🇹 · Andrea Ferroglia🇺🇸 · Simone Lavacca🇮🇹 · Andreas von Manteuffel🇺🇸

    We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equations, we expand the integrals in powers of the dimensional regulator $ϵ$ and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.

    hep-phJHEP(2019)·27 citations
16. 16*

    A $\mu$-$\tau$-philic scalar doublet under $Z_n$ flavor symmetry

    Yoshihiko Abe🇯🇵 · Takashi Toma🇨🇦 · Koji Tsumura🇯🇵

    We propose a minimal model which accommodates the long-standing anomaly of muon magnetic moment based on abelian discrete flavor symmetries. The standard model is extended by scalar doublets charged under a $Z_n$ lepton flavor symmetry. In these models, a large contribution to the muon magnetic moment can be obtained by the chirality enhancement from new scalar mediated diagrams without conflicting with the flavor symmetry. Thanks to the lepton flavor symmetry, these models automatically forbid lepton flavor violation. The minimal model is based on $Z_4$ symmetry with only one extra scalar doublet. In this model, we show that the parameter space favored by the muon $g-2$ can easily be consistent with experimental constraints and theoretical bounds such as the electroweak precision tests, lepton universality, potential stability condition and triviality bound as well as the LHC direct search mass bound. The new contributions to the muon electric dipole moment and the Higgs decay into $\gamma \gamma$ can be indirect signals of the model.

    hep-phJHEP(2019)·22 citations
17. 17*

    A new approach to the LSZ reduction formula

    John Collins🇺🇸

    Lehmann, Symanzik and Zimmermann (LSZ) proved a theorem showing how to obtain the S-matrix from time-ordered Green functions. Their result, the reduction formula, is fundamental to practical calculations of scattering processes. A known problem is that the operators that they use to create asymptotic states create much else besides the intended particles for a scattering process. In the infinite-time limits appropriate to scattering, the extra contributions only disappear in matrix elements with normalizable states, rather than in the created states themselves, i.e., the infinite-time limits of the LSZ creation operators are weak limits. The extra particles that are created are in a different region of space-time than the intended scattering process. To be able to work with particle creation at non-asymptotic times, e.g., to give a transparent and fully deductive treatment for scattering with long-lived unstable particles, it is necessary to have operators for which the infinite-time limits are strong limits. In this paper, I give an improved method of constructing such operators. I use them to give an improved systematic account of scattering theory in relativistic quantum field theories, including a new proof of the reduction formula. I make explicit calculations to illustrate the problems with the LSZ operators and their solution with the new operators. Not only do these verify the existence of the extra particles created by the LSZ operators and indicate a physical interpretation, but they also show that the extra components are so large that their contribution to the norm of the state is ultra-violet divergent in renormalizable theories. Finally, I discuss the relation of this work to the work of Haag and Ruelle on scattering theory.

    hep-phhep-th31 citations
18. 18*

    Collider Constraints on $Z^{\prime }$ Models for Neutral Current $B-$Anomalies

    B.C. Allanach🇬🇧 · J.M. Butterworth🇬🇧 · Tyler Corbett🇩🇰

    We examine current collider constraints on some simple $Z^{\prime }$ models that fit neutral current $B-$anomalies, including constraints coming from measurements of Standard Model (SM) signatures at the LHC. The `MDM' simplified model is not constrained by the SM measurements but {\em is} strongly constrained by a 139 fb${}^{-1}$ 13 TeV ATLAS di-muon search. Constraints upon the `MUM' simplified model are much weaker. A combination of the current $B_s$ mixing constraint and ATLAS' $Z^{\prime }$ search implies $M_{Z^{\prime }}>1.2$ TeV in the Third Family Hypercharge Model example case. LHC SM measurements rule out a portion of the parameter space of the model for $M_{Z^{\prime }}<1.5$ TeV.

    hep-phhep-exJHEP(2019)·66 citations
19. 19*

    Rare Top Decays as Probes of Flavorful Higgs Bosons

    Wolfgang Altmannshofer🇺🇸 · Brian Maddock🇺🇸 · Douglas Tuckler🇺🇸

    We study a version of Two Higgs Doublet Models with non-standard flavor violation in the up quark sector. We find branching ratios for the rare top decays $t\to hc$ and $t\to hu$ that are within reach of current and future colliders, while other flavor constraints from rare $B$ decays and neutral $D$ meson mixing, as well as constraints from Higgs signal strength measurements remain under control. The most prominent collider signature of the considered setup is $pp\to tH\to tt\bar{c}$, providing continued motivation to search for same-sign tops at the LHC as well as a simple framework to interpret these searches. As a byproduct of our study, we provide updated SM predictions for the rare top decays BR$(t\to hc{)}_{\text{SM}}=(4.19_{-0.80}^{+1.08}\pm 0.16)\times 10^{-15}$ and BR$(t\to hu{)}_{\text{SM}}=(3.66_{-0.70}^{+0.94}\pm 0.67)\times 10^{-17}$ with the main uncertainties coming from higher order QCD and CKM matrix elements.

    hep-phPRD(2019)·33 citations
20. 20*

    Master integrals for the NNLO virtual corrections to $q\bar{q}\to t\bar{t}$ scattering in QCD: the non-planar graphs

    Stefano Di Vita🇮🇹 · Thomas Gehrmann🇨🇭 · Stefano Laporta🇮🇹 · Pierpaolo Mastrolia🇮🇹 · Amedeo Primo🇨🇭 · Ulrich Schubert🇺🇸

    We complete the analytic evaluation of the master integrals for the two-loop non-planar box diagrams contributing to the top-pair production in the quark-initiated channel, at next-to-next-to-leading order in QCD. The integrals are determined from their differential equations, which are cast into a canonical form using the Magnus exponential. The analytic expressions of the Laurent series coefficients of the integrals are expressed as combinations of generalized polylogarithms, which we validate with several numerical checks. We discuss the analytic continuation of the planar and the non-planar master integrals, which contribute to $q\bar{q}\to t\bar{t}$ in QCD, as well as to the companion QED scattering processes $ee\to \mu \mu$ and $e\mu \to e\mu$.

    hep-phJHEP(2019)·33 citations
21. 21*

    Dynamical Axions and Gravitational Waves

    Djuna Croon🇨🇦 · Rachel Houtz🇪🇸 · Veronica Sanz🇬🇧

    In this paper we explore the possibility of observable gravitational waves as a manifestation of the QCD axion dynamics. In particular, we focus on dynamical axion models which solve the strong CP problem, and include the confinement of a QCD-like gauge group at the TeV scale. We study the resulting chiral symmetry breaking phase transition for models with $N_F=3$ and $N_F=4$ light flavors using the linear sigma model. This model describes the scalar meson spectrum and its interactions, with the diagonal field $\phi$ as the order parameter. We find that the amplitude of the gravitational wave spectrum depends on the mass of the dynamical axion ${\eta }^{\prime }$ via the ratio $m_{{\eta }^{\prime }}/m_{\phi }$. The resulting spectra may be observed at future mid-range gravitational wave experiments such as AION/MAGIS, DECIGO, and BBO. Moreover, the TeV states can be searched for at colliders and their quantum numbers characterized, providing a unique connection between axion physics, gravitational waves and collider searches.

    hep-phastro-ph.COJHEP(2019)·60 citations
22. 22*

    Constraining the deformed dispersion relation with the hydrogen atom 1S-2S transition

    Jin Pu🇨🇳 · Guo-Ping Li🇨🇳 · Qing-Quan Jiang🇨🇳 · Xiao-Tao Zu🇨🇳

    In this paper, we use the latest results of the ultra-high accuracy 1S-2S transition experiments in hydrogen atom to constrain the forms of the deformed dispersion relation in the nonrelativistic limit. For the leading correction of the nonrelativistic limit, the experiment sets a limit at an order of magnitude for the desired Planck-scale level, thereby providing another example of the Planck-scale sensitivity in the study of the dispersion relation in controlled laboratory experiments. And for the next-to-leading term, bound has two orders of magnitude away from the Planck scale, but it still amounts to the best limit, in contrast to previously obtained bound in the nonrelativistic limit from the cold-atom-recoil experiments.

    hep-phCPC(2020)·5 citations
23. 23*

    Gamma-Ray Bursts: Theoretical Issues and Developments

    P. Mészáros🇺🇸

    I discuss some aspects of the evolution of the standard GRB model, emphasizing various theoretical developments in the last decade, and review the impact of some of the most recent observational discoveries and the new challenges they pose in the expanding realm of multi-messenger astrophysics.

    ↳ astro-ph.HEhep-phMem.Soc.Ast.It.(2019)·23 citations
24. 24*

    Diversity in density profiles of self-interacting dark matter satellite halos

    Felix Kahlhoefer🇩🇪 · Manoj Kaplinghat🇺🇸 · Tracy R. Slatyer🇺🇸 · Chih-Liang Wu🇺🇸

    We present results from N-body simulations of self-interacting dark matter (SIDM) subhalos, which could host ultra-faint dwarf spheroidal galaxies, inside a Milky-Way-like main halo. We find that high-concentration subhalos are driven to gravothermal core collapse, while low-concentration subhalos develop large (kpc-sized) low-density cores, with both effects depending sensitively on the satellite's orbit and the self-interaction cross section over mass $\sigma /m$. The overall effect for $\sigma /m\gtrsim 3\mathrm{c}{\mathrm{m}}^2/g$ is to increase the range of inner densities, potentially explaining the observed diversity of Milky Way satellites, which include compact systems like Draco and Segue 1 that are dense in dark matter, and less dense, diffuse systems like Sextans and Crater II. We discuss possible ways of distinguishing SIDM models from collisionless dark matter models using the inferred dark matter densities and stellar sizes of the dwarf spheroidal galaxies.

    ↳ astro-ph.GAastro-ph.COhep-phJCAP(2019)·101 citations
25. 25*

    Neutrino Oscillations in a Quantum Processor

    C.A. Argüelles🇺🇸 · B.J.P. Jones🇺🇸

    Quantum computing technologies promise to revolutionize calculations in many areas of physics, chemistry, and data science. Their power is expected to be especially pronounced for problems where direct analogs of a quantum system under study can be encoded coherently within a quantum computer. A first step toward harnessing this power is to express the building blocks of known physical systems within the language of quantum gates and circuits. In this paper, we present a quantum calculation of an archetypal quantum system: neutrino oscillations. We define gate arrangements that implement the neutral lepton mixing operation and neutrino time evolution in two-, three-, and four-flavor systems. We then calculate oscillation probabilities by coherently preparing quantum states within the processor, time evolving them unitarily, and performing measurements in the flavor basis, with close analogy to the physical processes realized in neutrino oscillation experiments, finding excellent agreement with classical calculations. We provide recipes for modeling oscillation in the standard three-flavor paradigm as well as beyond-standard-model scenarios, including systems with sterile neutrinos, non-standard interactions, Lorentz symmetry violation, and anomalous decoherence.

    ↳ quant-phhep-exhep-phPRResearch(2019)·35 citations
26. 26*

    Is Gravity the Weakest Force?

    Satoshi Shirai🇯🇵 · Masahito Yamazaki🇯🇵

    It has recently been suggested that "gravity is the weakest force" in any theory with a suitable UV completion within quantum gravity. One formulation of this statement is the scalar weak gravity conjecture, which states that gravity is weaker than the force originating from scalar fields. We study the scalar weak gravity conjecture in de Sitter space, and discuss its low-energy consequences in light of the experimental searches for fifth forces and violations of the equivalence principle. We point out that some versions of the scalar weak gravity conjecture forbid the existence of very light scalar particles, such as the quintessence and axion-like particles. The absence of the quintessence field means that these versions of the scalar weak gravity conjecture are in phenomenological tension with the recently-proposed de Sitter swampland conjecture and its refinements. Some other versions of the scalar weak gravity conjecture escape these constraints, and could have interesting phenomenological consequences.

    ↳ hep-thastro-ph.COgr-qchep-phClass.Quant.Grav.(2021)·18 citations
27. 27*

    Quantifying Correlated Truncation Errors in Effective Field Theory

    J. A. Melendez🇺🇸 · R. J. Furnstahl🇺🇸 · D. R. Phillips🇺🇸 · M. T. Pratola🇺🇸 · S. Wesolowski🇺🇸

    Effective field theories (EFTs) organize the description of complex systems into an infinite sequence of decreasing importance. Predictions are made with a finite number of terms, which induces a truncation error that is often left unquantified. We formalize the notion of EFT convergence and propose a Bayesian truncation error model for predictions that are correlated across the independent variables, e.g., energy or scattering angle. Central to our approach are Gaussian processes that encode both the naturalness and correlation structure of EFT coefficients. Our use of Gaussian processes permits efficient and accurate assessment of credible intervals, allows EFT fits to easily include correlated theory errors, and provides analytic posteriors for physical EFT-related quantities such as the expansion parameter. We demonstrate that model-checking diagnostics---applied to the case of multiple curves---are powerful tools for EFT validation. As an example, we assess a set of nucleon-nucleon scattering observables in chiral EFT. In an effort to be self contained, appendices include thorough derivations of our statistical results. Our methods are packaged in Python code, called gsum, that is available for download on GitHub.

    ↳ nucl-thhep-phnucl-exphysics.data-anPRC(2019)·189 citations
28. 28*

    Isospin violations at BESIII

    Hongrong Qi🇨🇳 · Wencheng Yan (for the BESIII Collaboration)🇨🇳

    At present very large data samples in the energy region of 2.0-4.6 GeV were accumulated by the BESIII detector, which is operated in the upgraded Beijing electron positron collider (BEPCII). These data samples provide an unprecedented opportunity in the study of light hadron spectra and charmonium(-like) decays. We review some experimental analyses related to isospin violations at BESIII in this proceeding, which can be classify into three categories: isospin violating processes with a $f_0(980)$ or $a_0^0(980)$ production, isospin violating processes with baryon final states, and isospin violating hadronic transitions in the charmonium system.

    ↳ hep-exhep-phPoS(2019)·1 citation
29. 29*

    Influence of finite volume effect on the Polyakov Quark-Meson model

    Niseem Magdy🇺🇸

    In the current work, we study the influence of a finite volume on $2+1$ $SU(3)$ Polyakov Quark-Meson model (PQM) order parameters, (fluctuations) correlations of conserved charges and the quark-hadron phase boundary. Our study of the PQM model order parameters and the (fluctuations) correlations of conserved charges indicates a sizable shift of the quark-hadron phase boundary to higher values of baryon chemical potential (${\mu }_B$) and temperature ($T$) for decreasing the system volume. The detailed study of such effect could have important implications for the extraction of the (fluctuations) correlations of conserved charges of the QCD phase diagram from heavy ion data.

    ↳ nucl-thhep-phUniverse(2019)·15 citations
30. 30*

    Search for $\gamma$-ray emission from dark matter particle interactions from Andromeda and Triangulum Galaxies with the Fermi Large Area Telescope

    Mattia Di Mauro🇺🇸 · Xian Hou🇨🇳 · Christopher Eckner🇸🇮 · Gabrijela Zaharijas🇸🇮 · Eric Charles🇺🇸

    The Andromeda (M31) and Triangulum (M33) galaxies are the closest Local Group galaxies to the Milky Way, being only 785 and 870 kpc away. These two galaxies provide an independent view of high-energy processes that are often obscured in our own Galaxy, including possible signals of dark matter (DM) particle interactions. The Fermi Large Area Telescope (Fermi-LAT) preliminary eight year list of sources includes both M31, which is detected as extended with a size of about 0.4${}^{\circ }$, and M33, which is detected as a point-like source. The spatial morphology of M31 $\gamma$-ray emission could trace a population of unresolved sources and energetic particles originating in sources not related to massive star formation. Alternatively, the $\gamma$-ray emission could also be an indication of annihilation or decay of DM particles. We investigate these two possibilities using almost 10 years of data from the Fermi LAT. An interpretation that involves only a DM $\gamma$-ray emission is in tension with the current limits from other searches, such as those targeting Milky Way dwarf spheroidal galaxies. When we include a template of astrophysical emission, tuned on $\gamma$-ray data or from observations of these galaxies in other wavelengths, we do not find any significant evidence for a DM contribution and we set limits for the annihilation cross section that probe the thermal cross section for DM masses up to a few tens of GeV in the $b\bar{b}$ and ${\tau }^{+}{\tau }^{-}$ channels. For models where the DM substructures have masses above $10^{-6}$ solar masses our limits probe the DM interpretation of the Fermi LAT Galactic center excess. We provide also the lower limit for the DM decay time assuming the same spatial models of the DM distribution in M31 and M33.

    ↳ astro-ph.HEhep-phPRD(2019)·45 citations
31. 31*

    Towards testing CMB anomalies using the kinetic and polarized Sunyaev Zel'dovich effects

    Juan I. Cayuso🇨🇦 · Matthew C. Johnson🇨🇦

    Measurements of the Cosmic Microwave Background (CMB) temperature anisotropies on large angular scales have uncovered a number of anomalous features of marginal statistical significance, such as a hemispherical power asymmetry, lack of power on large angular scales, and features in the power spectrum. Because the primary CMB temperature has been measured at the cosmic variance limit, determining if these anomalies are hints of new physics as opposed to foregrounds, systematics, or simply statistical flukes, requires new observables. In this paper, we highlight the potential contribution that future measurements of the kinetic Sunyaev-Zel'dovich effect (kSZ) and the polarized Sunyaev Zel'dovich effect (pSZ) could make in determining the physical nature of several CMB anomalies. The kSZ and pSZ effects, temperature and polarization anisotropies induced by scattering from free electrons in the reionized Universe, are the dominant blackbody contribution to the CMB on small angular scales. Using the technique of SZ tomography, measurements of kSZ and pSZ effects can be combined with galaxy surveys to reconstruct the remote CMB dipole and quadrupole fields, providing a 3-dimensional probe of large scale modes inside our Hubble volume. Building on previous work, we forecast the additional constraining power that these observables might offer for a representative set of anomaly models. We find that the remote CMB dipole and quadrupole contain a similar amount of information on anomaly models as the primary CMB polarization. The information from CMB temperature, polarization, and the remote dipole and quadrupole fields is complementary, and the full set of observables can improve constraints on anomaly models by a factor of $\sim 2-4$ using next-generation CMB experiments and galaxy surveys. This could be sufficient to definitively establish the physical origin of several CMB anomalies.

    ↳ astro-ph.COhep-phhep-thPRD(2020)·46 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.