Wed·Apr 10, 2019Wednesday·April 10, 2019

1. 01*

   The pQCD analysis to extract PDFs and ${\alpha }_s^{\mathrm{NLO}}(M_Z^2)$ from inclusive jet-hadron production data

   A. Vafaee🇮🇷 · A. B. Shokouhi🇮🇷

   This perturbative Quantum Chromo Dynamics (pQCD) analysis attempts to present a simultaneous determination of parton distribution functions (PDFs) and the strong coupling ${\alpha }_s(M_Z^2)$ from inclusion of inclusive H1 and ZEUS jet, DiJets and TriJets production cross sections data on the HERA I and II combined data, as the central data sets for probing the internal structure of proton. To present an accurate pQCD analysis, we separate the role and influence of inclusion jet production cross sections data from inclusion of the strong coupling ${\alpha }_s(M_Z^2)$ as an extra fit parameter parameter on the gluon distribution. We show inclusion of jet, DiJets and TriJets production cross sections data improves the consistency between experiment and theory of cross sections for neutral current (NC) and charged current (CC) interactions of deep inelastic $e^{\pm }p$ scattering on proton up to $\sim 2.8$~\%. In addition, we show inclusion of jet production cross section data and considering ${\alpha }_s(M_Z^2)$ as a pQCD free parameter not only reduce dramatically the uncertainty band of gluon distribution but also improve the consistency between experiment and theory of NC and CC deep inelastic $e^{\pm }p$ scattering cross sections up to $\sim 3.6$~\%. Our simultaneous determination of PDFs and the strong coupling ${\alpha }_s(M_Z^2)$ with inclusion of jet production cross sections data leads to ${\alpha }_s^{\mathrm{NLO}}(M_Z^2)=0.12041\pm 0.00086$, which is in a good agreement with world average and other individual measurements.

   hep-ph2 citations
2. 02*

   QCD evolution based evidence for the onset of gluon saturation in exclusive photo-production of vector mesons

   A. Arroyo Garcia🇲🇽 · M. Hentschinski🇲🇽 · K. Kutak🇵🇱

   We investigate photo-production of vector mesons J/Psi and Upsilon measured both at HERA and LHC, using 2 particular fits of inclusive unintegrated gluon distributions, based on non-linear Balitsky-Kovchegov evolution (Kutak-Sapeta gluon; KS) and next-to-leading order Balitsky-Fadin-Kuraev-Lipatov evolution (Hentschinski-Sabio Vera-Salas gluon; HSS). We find that linear next-to-leading order evolution can only describe production at highest energies, if perturbative corrections are increased to unnaturally large values; rendering this corrections to a perturbative size, the growth with energy is too strong and the description fails. At the same time, the KS gluon, which we explore both with and without non-linear corrections, requires the latter to achieve an accurate description of the energy dependence of data. We interpret this observation as a clear signal for the presence of high gluon densities in the proton, characteristic for the onset of gluon saturation.

   hep-phPLB(2019)·78 citations
3. 03*

   Extracting the longitudinal structure function FL(x,Q2) at small x from a Froissart-bounded parametrization of F2(x,Q2)

   L.P. Kaptari🇨🇳 · A.V. Kotikov🇷🇺 · N.Yu. Chernikova🇷🇺 · Pengming Zhang🇨🇳

   We present a method to extract, in the leading and next-to-leading order approximations, the longitudinal deep-inelastic scattering structure function FL(x,Q2) from the experimental data by relying on a Froissart-bounded parametrization of the transversal structure function F2(x,Q2) and, partially, on the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equations. Particular attention is paid on kinematics of low and ultra low values of the Bjorken variable x. Analytical expressions for FL(x,Q2) in terms of the effective parameters of the parametrization of F2(x,Q2) are presented explicitly. We argue that the obtained structure functions FL(x,Q2) within both, the leading and next-to-leading order approximations, manifestly obey the Froissart boundary conditions. Numerical calculations and comparison with available data from ZEUS and H1-Collaborations at HERA demonstrate that the suggested method provides reliable structure functions FL(x,Q2) at low x in a wide range of the momentum transfer (1 GeV2 < Q2 < 3000 GeV2) and can be applied as well in analyses of ultra-high energy processes with cosmic neutrinos.

   hep-phPRD(2019)·38 citations
4. 04*

   The Inhomogeneous Phase of Dense Skyrmion Matter

   Byung-Yoon Park🇰🇷 · Won-Gi Paeng🇰🇵 · Vicente Vento🇪🇸

   It was predicted qualitatively in ref.[1] that skyrmion matter at low density is stable in an inhomogeneous phase where skyrmions condensate into lumps while the remaining space is mostly empty. The aim of this paper is to proof quantitatively this prediction. In order to construct an inhomogeneous medium we distort the original FCC crystal to produce a phase of planar structures made of skyrmions. We implement mathematically these planar structures by means of the 't Hooft instanton solution using the Atiyah-Manton ansatz. The results of our calculation of the average density and energy confirm the prediction suggesting that the phase diagram of the dense skyrmion matter is a lot more complex than a simple phase transition from the skyrmion FCC crystal lattice to the half-skyrmion CC one. Our results show that skyrmion matter shares common properties with standard nuclear matter developing a skin and leading to a binding energy equation which resembles the Weiszaecker mass formula.

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

   Weyl Symmetry Inspired Inflation and Dark Matter

   Yong Tang🇯🇵 · Yue-Liang Wu🇨🇳

   Motivated by the Weyl scaling gauge symmetry, we present a theoretical framework to explain cosmic inflation and dark matter simultaneously. This symmetry has been resurrected in recent attempts to formulate the gauge theory of gravity. We show the inspired inflation model is well consistent with current observations and will be probed further by future experiments. Furthermore, we clarify and prove the stability of Weyl gauge boson in the general theory with multiple scalars. We show the massive Weyl gauge boson can be a dark matter candidate and give the correct relic abundance.

   hep-phastro-ph.COgr-qcPLB(2020)·27 citations
6. 06*

   The ${\rm Y}(1S)$ leptonic decay using the principle of maximum conformality

   Xu-Dong Huang🇨🇳 · Xing-Gang Wu🇨🇳 · Jun Zeng🇨🇳 · Qing Yu🇨🇳 · Jian-Ming Shen🇨🇳

   In the paper, we study the ${\rm Y}(1S)$ leptonic decay width $\Gamma ({\rm Y}(1S)\to {\ell }^{+}{\ell }^{-})$ by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, ${\Gamma }_{{\rm Y}(1S)\to e^{+}{e}^{-}}=1.262_{-0.175}^{+0.195}$ keV, where the error is squared average of those from ${\alpha }_s(M_Z)=0.1181\pm 0.0011$, $m_b=4.93\pm 0.03$ GeV and the choices of factorization scales within $\pm 10\%$ of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.

   hep-phEPJC(2019)·3 citations
7. 07*

   Strangelets -- Effects of Finite Size and Exact Color Singletness

   Dan M\{o}nster Jensen🇩🇰

   Matter consisting of up, down and strange quarks, socalled Strange Quark Matter, has been hypothesized to be stable in bulk, and conceivably stable or metastable in finite systems---strangelets---as an alternative state to ordinary baryonic matter. Strangelets, if they exist, may be relics from the hot and dense early universe, or they could be produced in high energy events, such as collisions of heavy nuclei at relativistic speeds. This thesis investigates the implications of various effects that affects the possible (meta-) stability of strangelets, such as finite size, distribution of quark states (shell model), interaction with a hadron gas, non-zero temperature and QCD constraints of color singletness of the wave function. These effects are studied within the phenomenological MIT bag model of quark matter using the multiple reflection expansion for a liquid drop model equation of state with comparison to a shell model. Finite size, non-zero temperature and color singlet constraints have a destabilizing effect on strangelets, and can suppress their production in heavy ion collisions. The work presented has been described in part in the following publications: Dan Mønster Jensen and Jes Madsen, Strangelets at Non-Zero Temperature, in Strangeness and Quark Matter, edited by G. Vassiliadis, A. D. Panagiotou, S. Kumar, and J. Madsen (World Scientific, Singapore, 1995), pp. 220--229. Jes Madsen, Dan M. Jensen, and Michael B. Christiansen, Color Singlet Suppression of Quark-Gluon Plasma Formation, Phys. Rev. C 53, 1883 (1996). Dan M. Jensen and Jes Madsen, Strangelets with Finite Entropy, Phys. Rev. D 53, R4719 (1996). Dan Mønster Jensen, Jes Madsen, and Michael B. Christiansen, Color Singlet Strangelets, Heavy Ion Phys. 4 (1-4), 387-394 (1996).

   hep-ph2 citations
8. 08*

   Octet meson spectra and chiral phase diagram in the improved soft-wall AdS/QCD model

   Zhen Fang🇨🇳 · Yue-Liang Wu🇨🇳 · Lin Zhang🇨🇳

   We give a further study on chiral phase diagram in the improved soft-wall AdS/QCD model with $2+1$ flavors. The equations of motion for the octet pseudoscalar, vector and axial-vector mesons are derived to compute the octet meson spectra and relevant decay constants, by which the model parameters are determined. The chemical potential effects on thermal transition of chiral condensate are investigated, which enables us to obtain the chiral phase diagram in the $\mu -T$ plane. We find that the critical end point linking the crossover transition with the first-order phase transition still exists and locates at $({\mu }_B,T_c)\simeq (390\text{MeV},145\text{MeV})$, which along with the crossover line are consistent with lattice result and experimental analysis from relativistic heavy ion collisions.

   hep-phPRD(2019)·15 citations
9. 09*

   Spin Hydrodynamic Generation in the Charged Subatomic Swirl

   Xingyu Guo🇨🇳 · Jinfeng Liao🇺🇸 · Enke Wang🇨🇳

   Recently there have been significant interests in the spin hydrodynamic generation phenomenon from multiple disciplines of physics. Such phenomenon arises from global polarization effect of microscopic spin by macroscopic fluid rotation and is expected to occur in the hot quark-gluon fluid (the ``subatomic swirl'') created in relativistic nuclear collisions. This was indeed discovered in experiments which however revealed an intriguing puzzle: a polarization difference between particles and anti-particles. We suggest a novel application of a general connection between rotation and magnetic field: a magnetic field naturally arises along the fluid vorticity in the charged subatomic swirl. We establish this mechanism as a new way for generating long-lived in-medium magnetic field in heavy ion collisions. Due to its novel feature, this new magnetic field provides a nontrivial explanation to the puzzling observation of a difference in spin hydrodynamic generation for particles and anti-particles in heavy ion collisions.

   hep-phSci.Rep.(2020)·51 citations
10. 10*

    Some like it hot: $R^2$ heals Higgs inflation, but does not cool it

    Fedor Bezrukov🇬🇧 · Dmitry Gorbunov🇷🇺 · Chris Shepherd🇬🇧 · Anna Tokareva🇷🇺

    Strong coupling in Higgs inflation at high energies hinders a joint description of inflation, reheating and low-energy dynamics. The situation may be improved with a proper UV completion of the model. A well-defined self-consistent way is to introduce an $R^2$-term into the action. In this modified model the strong coupling scale returns back to the Planck scale, which justifies the use of the perturbative methods in studies of the model dynamics after inflation. We investigate the reheating of the post-inflationary Universe, which involves two highly anharmonic oscillators strongly interacting with each other: homogeneous Higgs field and scalaron. We observe that in interesting regions of model parameter space these oscillations make longitudinal components of the weak gauge bosons tachyonic, triggering instant preheating at timescales much shorter than the Hubble time. The weak gauge bosons are heavy and decay promptly into light Standard Model particles, ensuring the onset of the radiation domination era right after inflation.

    hep-phhep-thPLB(2019)·49 citations
11. 11*

    Uncertainties in Direct Dark Matter Detection in Light of Gaia's Escape Velocity Measurements

    Youjia Wu🇺🇸 · Katherine Freese🇸🇪 · Chris Kelso🇺🇸 · Patrick Stengel🇸🇪 · Monica Valluri🇺🇸

    Direct detection experiments have set increasingly stringent limits on the cross section for spin-independent dark matter-nucleon interactions. In obtaining such limits, experiments primarily assume the standard halo model (SHM) as the distribution of dark matter in our Milky Way. Three astrophysical parameters are required to define the SHM: the local dark matter escape velocity, the local dark matter density and the circular velocity of the sun around the center of the galaxy. This paper studies the effect of the uncertainties in these three astrophysical parameters on the XENON1T exclusion limits using the publicly available DDCalc code. We compare limits obtained using the widely assumed escape velocity from the RAVE survey and the newly calculated escape velocity by Monari $et$ $al.$ using Gaia data. Our study finds that the astrophysical uncertainties are dominated by the uncertainty in the escape velocity (independent of the best fit value) at dark matter masses below 6 GeV and can lead to a variation of nearly 6 orders of magnitude in the exclusion limits at 4 GeV. Above a WIMP mass of 6 GeV, the uncertainty becomes dominated by the local dark matter density, leading to uncertainties of factors of $\sim$10 (3) at 6 (15) GeV WIMP mass in the exclusion limits. Additionally, this work finds that the updated best fit value for the escape velocity based on Gaia data leads to only very minor changes to the effects of the astrophysical uncertainties on the XENON1T exclusion limits.

    hep-phastro-ph.COJCAP(2019)·33 citations
12. 12*

    CP Violating Effects in Heavy Neutrino Oscillations: Implications for Colliders and Leptogenesis

    P. S. Bhupal Dev🇺🇸 · Rabindra N. Mohapatra🇺🇸 · Yongchao Zhang🇺🇸

    Two of the important implications of the seesaw mechanism are: (i) a simple way to understand the small neutrino masses, and (ii) the origin of matter-anti-matter asymmetry in the universe via the leptogenesis mechanism. For TeV-scale seesaw models, successful leptogenesis requires that the right-handed neutrinos (RHNs) must be quasi-degenerate and if they have CP violating phases, they also contribute to the CP asymmetry. We investigate this in the TeV-scale left-right models for seesaw and point out a way to probe the quasi-degeneracy possibility with CP violating mixings for RHNs in hadron colliders using simple observables constructed out of same-sign dilepton charge asymmetry (SSCA). In particular, we isolate the parameter regions of the model, where the viability of leptogenesis can be tested using the SSCA at the Large Hadron Collider, as well as future 27 TeV and 100 TeV hadron colliders. We also independently confirm an earlier result that there is a generic lower bound on the $W_R$ mass of about 10 TeV for leptogenesis to work.

    hep-phhep-exJHEP(2019)·30 citations
13. 13*

    Study of energy deposition patterns in hadron calorimeter for prompt and displaced jets using convolutional neural network

    Biplob Bhattacherjee🇮🇳 · Swagata Mukherjee🇩🇪 · Rhitaja Sengupta🇮🇳

    Sophisticated machine learning techniques have promising potential in search for physics beyond Standard Model in Large Hadron Collider (LHC). Convolutional neural networks (CNN) can provide powerful tools for differentiating between patterns of calorimeter energy deposits by prompt particles of Standard Model and long-lived particles predicted in various models beyond the Standard Model. We demonstrate the usefulness of CNN by using a couple of physics examples from well motivated BSM scenarios predicting long-lived particles giving rise to displaced jets. Our work suggests that modern machine-learning techniques have potential to discriminate between energy deposition patterns of prompt and long-lived particles, and thus, they can be useful tools in such searches.

    hep-phJHEP(2019)·25 citations
14. 14*

    Minimal Two-component Scalar Doublet Dark Matter with Radiative Neutrino Mass

    Debasish Borah🇮🇳 · Rishav Roshan🇮🇳 · Arunansu Sil🇮🇳

    We propose a minimal extension of the Standard Model to accommodate two-component dark matter (DM) and light neutrino mass. The symmetry of the Standard Model is enhanced by an unbroken ${\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\prime }$ such that being odd under each ${\mathbb{Z}}_2$, there exists one right handed neutrino and one inert scalar doublet. Therefore, each of the ${\mathbb{Z}}_2$ sectors contribute to ($i$) light neutrino masses radiatively similar to the scotogenic models while ($ii$) the two neutral CP even scalars present in two additional inert doublets play the role of dark matters. Focusing on the intermediate range of inert scalar doublet DM scenario: $M_W\le M_{\mathrm{DM}}\lesssim 500\mathrm{GeV}$, where one scalar doublet DM can not satisfy correct relic, we show that this entire range becomes allowed within this two-component scalar doublet DM, thanks to the inter-conversion between the two DM candidates in presence of neutrino Yukawa couplings with dark sector.

    hep-phastro-ph.COPRD(2019)·42 citations
15. 15*

    Common origin of modified chaotic inflation, non thermal dark matter and Dirac neutrino mass

    Debasish Borah🇮🇳 · Dibyendu Nanda🇮🇳 · Abhijit Kumar Saha🇮🇳

    We propose a minimal extension of the standard model of particle physics to accommodate cosmic inflation, dark matter and light neutrino masses. While the inflationary phase is obtained from a modified chaotic inflation scenario, consistent with latest cosmology data, the dark matter particle is a fermion singlet which remains out of equilibrium in the early universe. The scalar field which revives the chaotic inflation scenario by suitable modification also assists in generating tiny couplings of dark matter with its mother particle, naturally realizing the non-thermal or freeze-in type dark matter scenario. Interestingly, the same assisting scalar field also helps in realizing tiny Yukawa couplings required to generate sub-eV Dirac neutrino mass from neutrino couplings to the standard model like Higgs field. The minimality as well as providing a unified solution to all three problems keep the model predictive at experiments spanning out to all frontiers.

    hep-phastro-ph.COPRD(2020)·25 citations
16. 16*

    SPD - the Spin Physics Project with Polarized Proton and Deuteron Beams at the NICA Collider

    A. Guskov (on behalf of the SPD working group)🇷🇺

    The SPD experiment at the future NICA collider at JINR (Dubna, Russia) aims to investigate the nucleon spin structure and polarization phenomena in collisions of longitudinally and transversely polarized protons and deuterons at $\sqrt{s}$ up to 27 GeV and luminosity up to 10${}^{32}$ cm${}^{-2}$ s${}^{-1}$. Measurement of asymmetries in the Drell-Yan pairs, charmonium and prompt photon production can provide an access to the full set of leading twist TMD PDFs in nucleons. The experimental setup is planned as a universal 4$\pi$ detector for a wide range of physics tasks.

    ↳ hep-exhep-phJPS Conf.Proc.(2019)·3 citations
17. 17*

    Permanent mean spin source of the chiral magnetic effect in neutron stars

    Maxim Dvornikov (1 and 2)🇷🇺 · Victor B. Semikoz (1) ((1) IZMIRAN, (2) Tomsk State University)🇷🇺

    We suggest the generalization of the Anomalous Magneto-Hydro-Dynamics (AMHD) in the chiral plasma of a neutron star (NS) accounting for the mean spin in the ultrarelativistic degenerate electron gas within the magnetized NS core as a continuing source of the chiral magnetic effect. Using the mean field dynamo model generalized in AMHD, one can obtain the growth of a seed magnetic field up to $10^{18}\text{G}$ for an old non-superfluid NS at its neutrino cooling era $t<10^6\text{yr}$, while neglecting any matter turbulence within its core and assuming the rigid NS rotation. The application of the suggested approach to the evolution of magnetic fields observed in magnetars, $B\sim 10^{15}\text{G}$, should be self-consistent with all approximations used in the suggested laminar dynamo, at least, up to the jumps of growing fields.

    ↳ astro-ph.HEhep-phJCAP(2019)·7 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.