Tue·Apr 28, 2020Tuesday·April 28, 2020

1. 01*

   Neutrino Self-Interactions and Double Beta Decay

   Frank F. Deppisch🇬🇧 · Lukas Graf🇩🇪 · Werner Rodejohann🇩🇪 · Xun-Jie Xu🇩🇪

   Neutrino Self-Interactions ($\nu$SI) beyond the Standard Model are an attractive possibility to soften cosmological constraints on neutrino properties and also to explain the tension in late and early time measurements of the Hubble expansion rate. The required strength of $\nu$SI to explain the $4\sigma$ Hubble tension is in terms of a point-like effective four-fermion coupling that can be as high as $10^9{G}_F$, where $G_F$ is the Fermi constant. In this work, we show that such strong $\nu$SI can cause significant effects in two-neutrino double beta decay, leading to an observable enhancement of decay rates and to spectrum distortions. We analyze self-interactions via an effective operator as well as when mediated by a light scalar. Data from observed two-neutrino double beta decay is used to constrain $\nu$SI, which rules out the regime around $10^9{G}_F$.

   hep-phastro-ph.COhep-exPRD(2020)·80 citations
2. 02*

   Threshold Resummation for Hadron Production in the Small-$x$ Region

   Hao-Yu Liu🇨🇳 · Zhong-Bo Kang🇺🇸 · Xiaohui Liu🇨🇳

   We study the single hadron inclusive production in the forward rapidity region in proton-nucleus collisions. We find the long-standing negative cross section at next-to-leading-order (NLO) is driven by the large negative threshold logarithmic contributions. We established a factorization theorem for resumming these logarithms with systematically improvable accuracy within the color glass condensate formalism. We demonstrate how the threshold leading logarithmic accuracy can be realized by a suitable scale choice in the NLO results. The NLO spectrums with the threshold logarithms resummed remain positive and impressive agreements with experimental data are observed.

   hep-phhep-exnucl-exnucl-thPRD(2020)·38 citations
3. 03*

   Quasiclassical approach to synergic synchrotron-Cherenkov radiation in polarized vacuum

   I. I. Artemenko🇷🇺 · E. N. Nerush🇷🇺 · I. Yu. Kostyukov🇷🇺

   The photon emission by an ultrarelativistic charged particle in extremely strong magnetic field is analyzed, with vacuum polarization and photon recoil taken into account. The vacuum polarization is treated phenomenologically via refractive index. The photon emission occurs in the synergic (cooperative) synchrotron-Cherenkov process [J. Schwinger, W. Tsai and T. Erber, Annals of Physics, 96 303 (1976)] which is similar to the synchrotron emission rather than to the Cherenkov one. For electrons, the effect of the vacuum polarization on the emission spectrum is not evident even beyond the probable onset of non-perturbative quantum electrodynamics (QED). However, the effect of the vacuum polarization on the emission spectrum can be observable for muons already at $\gamma B/B_S\approx 30$, with $\gamma$ the muon Lorentz factor, $B$ the magnetic field strength and $B_S$ the critical QED field. Nevertheless, vacuum polarization leads to only 10% enhancement of the maximum of the radiation spectrum.

   hep-phphysics.plasm-phNew J.Phys.(2020)·7 citations
4. 04*

   Gauge dependence of the perturbative QCD predictions under the momentum space subtraction scheme

   Jun Zeng🇨🇳 · Xing-Gang Wu🇨🇳 · Xu-Chang Zheng🇨🇳 · Jian-Ming Shen🇨🇳

   The momentum space subtraction (MOM) scheme is one of the most frequently used renormalization schemes in perturbative QCD (pQCD) theory. In the paper, we make a detailed discussion on the gauge dependence of the pQCD prediction under the MOM scheme. Conventionally, there is renormalization scale ambiguity for the fixed-order pQCD predictions, which assigns an arbitrary range and an arbitrary error for the fixed-order pQCD prediction. The principle of maximum conformality (PMC) adopts the renormalization group equation to determine the magnitude of the coupling constant and hence determines an effective momentum flow of the process, which is independent to the choice of renormalization scale. There is thus no renormalization scale ambiguity in PMC predictions. To concentrate our attention on the MOM gauge dependence, we first apply the PMC to deal with the pQCD series. We adopt the Higgs boson decay width, $\Gamma (H\to gg)$, up to five-loop QCD contributions as an example to show how the gauge dependence behaves before and after applying the PMC. It is found that the Higgs decay width $\Gamma (H\to gg)$ depends very weakly on the choices of the MOM schemes, being consistent with the renormalization group invariance. It is found that the gauge dependence of $\Gamma (H\to gg)$ under the $\mathrm{MOMgg}$ scheme is less than $\pm 1\%$, which is the smallest gauge dependence among all the mentioned MOM schemes.

   hep-phCPC(2020)·13 citations
5. 05*

   Four-quark exotic mesons

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   We review our investigations devoted to the analysis of the resonances $Z_c(3900)$, $Z_c(4430)$, $Z_c(4100)$, $X(4140)$, $X(4274)$, $a_1(1420)$ , $Y(4660)$, $X(2100)$, $X(2239)$ and $Y(2175)$ discovered in various processes by Belle, BaBar, BESIII, D0, CDF, CMS, LHCb and COMPASS collaborations. These resonances are considered as serious candidates to four-quark (tetraquark) exotic mesons. We treat all of them as diquark-antidiquark states with relevant spin-parities, find their masses and couplings, as well as explore their dominant strong decay channels. Calculations are performed in the context of the QCD sum rule method. Thus, the spectroscopic parameters of the tetraquarks are evaluated using the two-point sum rules. For computations of the strong couplings $G_{T{M}_1{M}_2}$, corresponding to the vertices $T{M}_1{M}_2$ and necessary to find the partial widths of the strong decays $T\to M_1{M}_2$, we employ either the three-point or full/approximate versions of the QCD light-cone sum rules methods. Obtained results are compared with available experimental data, and with predictions of other theoretical studies.

   hep-phhep-exhep-latTurk.J.Phys.(2020)·119 citations
6. 06*

   Higgs boson to $\gamma Z$ decay as a probe of flavour changing neutral Yukawa couplings

   Shi-Ping He🇨🇳

   With the deeper study of Higgs particle, Higgs precision measurements can be served to probe new physics indirectly. In many new physics models, vector-like quarks $T_L,T_R$ occur naturally. It is important to probe their couplings with standard model particles. In this work, we consider the singlet $T_L,T_R$ extended models and show how to constrain the $Tth$ couplings through the $h\to \gamma Z$ decay at high-luminosity LHC. Firstly, we derive the perturbative unitarity bounds on $|y_{L,R}^{tT}|$ with other couplings set to be zeros simply. To optimize the situation, we take $m_T$ = 400 GeV and $s_L$ = 0.2 considering the experimental constraints. Under this benchmark point, we find that the future bounds from $h\to \gamma Z$ decay can limit the real parts of $y_{L,R}^{tT}$ in the positive direction to be O(1) because of the double enhancement. For the real parts of $y_{L,R}^{tT}$ in the negative direction, it is always surpassed by the perturbative unitarity. Moreover, we find that the top quark electric dipole moment can give stronger bounds (especially the imaginary parts of $y_{L,R}^{tT}$) than the perturbative unitarity and $h\to \gamma Z$ decay in the off-axis regions for some scenarios.

   hep-phPRD(2020)·11 citations
7. 07*

   Mass Correction to Chiral Kinetic Equations

   Ziyue Wang🇨🇳 · Xingyu Guo🇨🇳 · Shuzhe Shi🇨🇦 · Pengfei Zhuang🇨🇳

   We study fermion mass correction to chiral kinetic equations in electromagnetic fields. Different from the chiral limit where fermion number density is the only independent distribution, the number and spin densities are coupled to each other for massive fermion systems. To the first order in $\hslash$, we derived the quantum correction to the classical on-shell condition and the Boltzmann-type transport equations. To the linear order in the fermion mass, the mass correction does not change the structure of the chiral kinetic equations and behaves like additional collision terms. While the mass correction exists already at classical level in general electromagnetic fields, it is only a first order quantum correction in the study of chiral magnetic effect.

   hep-phhep-thNPA(2021)·7 citations
8. 08*

   Supernova neutrino scattering off Gadolinium odd isotopes in water Cherenkov detectors

   Paraskevi C. Divari🇬🇷

   In this work, the supernova neutrino(SN) charged-current interactions with Gd odd isotopes (A=155 and 157) are studied. We use measured spectra and the quasiparticle-phonon model (MQPM) to calculate the charged current response of odd Gd isotopes to supernova neutrinos. Flux-averaged cross-sections are obtained considering quasi-thermal neutrino spectra.

   hep-phastro-ph.IMJCAP(2020)·1 citation
9. 09*

   Pinning down the gauge boson couplings in $WW\gamma$ production using forward proton tagging

   Seddigheh Tizchang🇮🇷 · Seyed Mohsen Etesami🇮🇷

   In this paper, we explore the potential of the LHC to measure the rate of $\mathrm{pp}\to \mathrm{p}WW\gamma \mathrm{p}$ process, also to probe the new effective couplings contributing to the $WW\gamma$ and $WW\gamma \gamma$ vertices. The analysis is performed at the $\sqrt{s}=13$ TeV, in the di-leptonic decay channel, and assuming 300 $f{b}^{-1}$ integrated luminosity (IL). In addition to the presence of two opposite sign leptons, a photon, and missing energy, the distinctive signature of this process is the presence of two intact protons flying few millimeters from the initial beam direction in both sides of interaction points which suppress the background process effectively. To exploit this feature of signal we benefit from forward detectors (FDs) placed about 200 meters from the interaction point to register the kinematics of tagged protons. In order to overcome the major sources of backgrounds, we introduced three categories of selection cuts dealing with objects that strike the central detector, protons hitting the FDs, and correlations of central objects and protons, respectively. We also evaluate the probability of pile-up protons to be tagged in the FDs as a function of the mean number of pile-up. Then the sensitivity of the LHC to observe this process and constraints on multi-boson effective couplings are extracted. The obtained expected limits show very good improvements for dimension-8 quartic couplings and competitive bounds on dimension-6 anomalous triple couplings w.r.t the current experimental limits. Therefore, we propose this process to the LHC experiments as a sensitive and complementary channel to study the multi-gauge boson couplings.

   hep-phJHEP(2020)·17 citations
10. 10*

    Muon conversion to electron in nuclei in Minimal R-symmetric Supersymmetric Standard Model

    Ke-Sheng Sun🇨🇳 · Sheng-Kai Cui🇨🇳 · Wei Li🇨🇳 · Hai-Bin Zhang🇨🇳

    We analyze the lepton flavor violating process $\mu -e$ conversion in the framework of the minimal R-symmetric supersymmetric standard model. The theoretical predictions are determined by considering the experimental constraint on parameter ${\delta }^{12}$ from the lepton flavor violating decay $\mu \to e\gamma$. The numerical results show that $\gamma$ penguins and Z penguins dominate the predictions on CR($\mu -e$,Nucleus), and the contributions from Higgs penguins and box diagrams are insignificant. The theoretical predictions on conversion rate CR($\mu -e$,Nucleus) in a Al or Ti target can be enhanced close to the future experimental sensitivities and are very promising to be observed in near future experiment.

    hep-phPRD(2020)·6 citations
11. 11*

    Mass distribution of magnetized quark-nugget dark matter and comparison with observations

    J. Pace VanDevender (VanDevender Enterprises LLC)🇺🇸 · Ian Shoemaker (Virginia Tech)🇺🇸 · T. Sloan (Lancaster University, UK)🇬🇧 · Aaron P. VanDevender (Founders Fund)🇺🇸 · Benjamin A. Ulmen (Sandia National Laboratories)🇺🇸

    Quark nuggets are a candidate for dark matter consistent with the Standard Model. Previous models of quark nuggets have investigated properties arising from their being composed of strange, up, and down quarks and have not included any effects caused by their self-magnetic field. However, Tatsumi found that the core of a magnetar star may be a quark nugget in a ferromagnetic state with core magnetic field B between $10^{11}$ T and $10^{13}$ T. We apply Tatsumi${}^{\prime }$s result to quark-nugget dark-matter and report results on aggregation of magnetized quark nuggets (MQNs) after formation from the quark-gluon plasma until expansion of the universe freezes out the mass distribution to include $10^{-24}$ kg to $10^{14}$ kg. Aggregation overcomes weak-interaction decay. Computed mass distributions show MQNs are consistent with requirements for dark matter and indicate that geologic detectors (craters in peat bogs) and space-based detectors (satellites measuring radio-frequency emissions after passage through normal matter) should be able to detect MQN dark matter. Null and positive observations narrow the range of a key parameter B to between $10^{11}$ T and 3 $10^{13}$ T.

    hep-phastro-ph.COastro-ph.GAgr-qcSci.Rep.(2020)·7 citations
12. 12*

    Sequential hadronization in heavy ion collisions

    Jiaxing Zhao🇨🇳 · Shuzhe Shi🇨🇦 · Nu Xu🇨🇳 · Pengfei Zhuang🇨🇳

    Heavy flavor supplies a chance to constrain and improve the hadronization mechanism. We have established a sequential coalescence model with charm conservation and applied it to the charmed hadron production in heavy ion collisions. The charm conservation enhances the earlier hadron production and suppresses the later production. This relative enhancement (suppression) changes significantly the ratios between charmed hadrons in heavy ion collisions.

    hep-phnucl-thNPA(2021)·3 citations
13. 13*

    Isovector and isoscalar tensor form factors of $N(1535)\to N$ transition in light-cone QCD

    Ulaş Özdem🇹🇷

    We have applied isovector and isoscalar tensor current to evaluate the tensor form factors of the $N(1535)\to N$ transition with the help of the light-cone QCD sum rule method. In numerical computations, have used the most general forms of the interpolating current for the nucleon and the tensor current together with two different sets of the input parameters in the DAs of the $N(1535)$ state. We have obtained that the values of $N(1535)\to N$ transition tensor form factors very sensitive to the input parameters of the distribution amplitudes of the $N(1535)$ state. We have acquired that the $Q^2$ dependence of $N(1535)\to$ transition tensor form factors is well defined by a p-pole fit function.

    hep-phhep-exhep-latPRD(2020)·4 citations
14. 14*

    Extracting maximum information from polarised baryon decays via amplitude analysis: the ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$ case

    Daniele Marangotto🇮🇹

    We consider which is the maximum information measurable from the decay distributions of polarised baryon decays via amplitude analysis in the helicity formalism. We focus in particular on the analytical study of the ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$ decay distributions, demonstrating that the full information on its decay amplitudes can be extracted from its distributions, allowing a simultaneous measurement of both helicity amplitudes and the polarisation vector. This opens the possibility to use the ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$ decay for applications ranging from New Physics searches to low-energy QCD studies, in particular its use as absolute polarimeter for the ${\Lambda }_c^{+}$ baryon. This result is valid as well for baryon decays having the same spin structure and it is cross-checked numerically by means of a toy amplitude fit with Monte Carlo pseudo-data.

    hep-phhep-exAdv.High Energy Phys.(2020)·12 citations
15. 15*

    Clocking Out Superradiance Limits

    Anubhav Mathur🇺🇸 · Surjeet Rajendran🇺🇸 · Erwin H. Tanin🇺🇸

    The superradiant instability of black hole space-times has been used to place limits on ultra-light bosonic particles. We show that these limits are model dependent. While the initial growth of the mode is gravitational and thus model independent, the ability to place a limit on new particles requires the mode to grow unhindered to a large number density. Non-linear interactions between the particle and other light degrees of freedom that are mediated through higher dimension operators can damp this growth, eliminating the limit. However, these non-linearities may also destroy a cosmic abundance of these light particles, an attractive avenue for their discovery in several experiments. We study the specific example of the QCD axion and show that it is easy to construct models where these non-linearities eliminate limits from superradiance while preserving their cosmic abundance.

    hep-phastro-ph.COgr-qcPRD(2020)·33 citations
16. 16*

    RGE-induced $\mu$-$\tau$ symmetry breaking: an analysis of the latest T2K results

    Guo-yuan Huang🇨🇳 · Newton Nath🇲🇽

    The T2K collaboration has recently reported their results, which gives the best-fit values of the atmospheric mixing angle ${\sin }^2{\theta }_{23}=0.53$ and the Dirac CP-violating phase $\delta =-1.89$ for normal neutrino mass ordering. We give a possible theoretical origin of such values based on the $\mu$-$\tau$ reflection symmetry. It has been found that the breaking of such symmetry using one-loop renormalization-group equations (RGEs) in the framework of minimal supersymmetric standard model can fit well with the latest T2K results and the recent global fits. To make a quantitative analysis, we have included for the first time the complete dataset of oscillation, beta decay, neutrinoless double-beta decay and cosmological observations in comparing the theory to experiments. We also further examine the importance of such breaking patterns for neutrinoless double-beta decay experiments.

    hep-phhep-exEPJC(2020)·13 citations
17. 17*

    Towards the decay properties of deuteron-like state $d_{N\Omega }$

    Cheng-Jian Xiao🇨🇳 · Yu-Bing Dong🇨🇳 · Thomas Gutsche🇩🇪 · Valery E. Lyubovitskij🇩🇪 · Dian-Yong Chen🇨🇳

    Recent lattice QCD calculations showed that a $d_{N\Omega }$ dibaryon state similar to the deuteron with small binding energy may exist. In this work we propose a hadronic molecular approach to study the dynamical properties of this exotic state. We use a phenomenological Lagrangian approach to describe the coupling of the $d_{N\Omega }$ state to its constituents and the decays into conventional hadrons, $d_{N\Omega }\to \Lambda \Xi$ and $d_{N\Omega }\to \Sigma \Xi$. Predictions for the sum of the decay rates are in the range of a few hundred keV. In addition, we find that the $d_{N\Omega }\to \Lambda \Xi$ mode is dominant, preferably searched for in a future RHIC experiment.

    hep-phPRD(2020)·15 citations
18. 18*

    Radiative decays of heavy-light quarkonia through $M1$, and $E1$ transitions in the framework of Bethe-Salpeter equation

    Shashank Bhatnagar🇮🇳 · Eshete Gebrehana🇪🇹

    In this work we study the radiative decays of heavy-light quarkonia through M1 and E1 transitions, that involve quark-triangle diagrams with two hadron vertices, and are difficult to evaluate in BSE-CIA. We have expressed the transition amplitude, $M_{fi}$ as a linear superposition of terms involving all possible combinations of $++$, and $--$ components of Salpeter wave functions of final and initial hadron, with coefficients being related to results of pole integrals over complex $\sigma$- plane. We evaluate the decay widths for $M1$ transitions (${}^3{S}_1{\to }^1{S}_0+\gamma$), and $E1$ transitions (${}^3{S}_1{\to }^1{P}_0+\gamma$ and ${}^1{P}_0{\to }^3{S}_1+\gamma$). We have used algebraic forms of Salpeter wave functions obtained through analytic solutions of mass spectral equations for ground and excited states of $0^{++},1^{--}$, and $0^{-+}$ heavy-light quarkonia in approximate harmonic oscillator basis, to calculate their decay widths. The input parameters used by us were obtained by fitting to their mass spectra. We have compared our results with experimental data and other models, and found reasonable agreements.

    hep-phPRD(2020)·20 citations
19. 19*

    Inclusive diffractive ${\eta }_{\mathrm{c}}$ production in pp, pA and AA modes at the LHC

    Tichouk🇨🇳 · Hao Sun🇨🇳 · Xuan Luo🇨🇳

    In this paper, the inclusive Pomeron-Pomeron, Reggeon-Reggeon, Pomeron-Reggeon as well as gluon-Pomeron(-Reggeon) and photon-Pomeron(-Reggeon) interactions for the ${\eta }_{\mathrm{c}}$ at the LHC energies have been examined in proton-proton, proton-nucleus and nucleus-nucleus collision modes. The cross section has been computed based on the NRQCD factorization and Regge theory formalism. The cross exchange of Pomeron-Reggeon contribution is important in $\mathrm{pp}$ and $\mathrm{pA}$ modes. The Pomeron-Pomeron contribution is significant in $\mathrm{AA}$ mode. The Pomeron contribution is considerable for $\mathrm{AA}$ and $\mathrm{pA}$ modes in single diffractive process where $\mathrm{A}$ undergoes the diffractive process. Reggeon contribution is sizable in $\mathrm{pp}$ and $\mathrm{pA}$ modes where $\mathrm{p}$ only undergoes the diffractive process. The Pomeron and Reggeon contributions in photon-Pomeron and-Reggeon process remain smaller than that of gluon-Pomeron and-Reggeon processes. Our results show that the experimental study of Reggeon, Pomeron and their cross exchange can be carried out in certain kinematic windows with the specific choice of the mode at the LHC. The investigation can be useful to better constrain the Reggeon and Pomeron parton content. The inclusive process serves as the background to related exclusive processes which should be predicted.

    hep-phPRD(2020)·6 citations
20. 20*

    Modular Invariant Models of Leptons at Level 7

    Gui-Jun Ding🇨🇳 · Stephen F. King🇬🇧 · Cai-Chang Li🇨🇳 · Ye-Ling Zhou🇬🇧

    We consider for the first time level 7 modular invariant flavour models where the lepton mixing originates from the breaking of modular symmetry and couplings responsible for lepton masses are modular forms. The latter are decomposed into irreducible multiplets of the finite modular group ${\Gamma }_7$, which is isomorphic to $PSL(2,Z_7)$, the projective special linear group of two dimensional matrices over the finite Galois field of seven elements, containing 168 elements, sometimes written as $PS{L}_2(7)$ or $\Sigma (168)$. At weight 2, there are 26 linearly independent modular forms, organised into a triplet, a septet and two octets of ${\Gamma }_7$. A full list of modular forms up to weight 8 are provided. Assuming the absence of flavons, the simplest modular-invariant models based on ${\Gamma }_7$ are constructed, in which neutrinos gain masses via either the Weinberg operator or the type-I seesaw mechanism, and their predictions compared to experiment.

    hep-phJHEP(2020)·73 citations
21. 21*

    A QCD analysis of near-threshold quarkonium leptoproduction at large photon virtualities

    Renaud Boussarie🇺🇸 · Yoshitaka Hatta🇺🇸

    We propose a novel approach to compute the cross section of near-threshold $J/\psi$ and ${\rm Y}$ production in electron-proton scattering at large photon virtualities $Q^2$ based on an operator product expansion. We show that the process can be used to extract the gluon part of the D-term gravitational form factor of the proton. At the subleading level, it is also sensitive to the trace anomaly effect of QCD.

    hep-phnucl-exPRD(2020)·51 citations
22. 22*

    Nonradiative ${\alpha }^{7}m$ QED effects in Lamb shift of helium triplet states

    Vojtěch Patkóš🇨🇿 · Vladimir A. Yerokhin🇷🇺 · Krzysztof Pachucki🇵🇱

    Theoretical predictions for the Lamb shift in helium are limited by unknown quantum electrodynamic effects of the order ${\alpha }^{7}m$, where $\alpha$ is the fine-structure constant and $m$ is the electron mass. We make an important step towards the complete calculation of these effects by deriving the most challenging part, which is induced by the virtual photon exchange between all three helium particles, the two electrons, and the nucleus. The complete calculation of the ${\alpha }^{7}m$ effect including the radiative corrections will allow comparing of the nuclear charge radii determined from the electronic and muonic helium atoms and thus provide a stringent test of the Standard Model of fundamental interactions.

    hep-phphysics.atom-phPRA(2020)·11 citations
23. 23*

    Multiplicity Moments using Tsallis Statistics in High-Energy Hadron-Nucleus Interactions

    S. Sharma🇮🇳 · G. Chaudhary🇮🇳 · K. Sandeep🇮🇳 · A. Singla🇮🇳 · M. Kaur🇮🇳

    The study of higher-order moments of a distribution and its cumulants constitute a sensitive tool to investigate the correlations between the particle produced in high energy interactions. In our previous work we have used the Tsallis $q$ statistics, NBD, Gamma and shifted Gamma distributions to describe the multiplicity distributions in ${\pi }^{-}$ -nucleus and $p$ -nucleus fixed target interactions at various energies ranging from P${}_{Lab}$ = 27 GeV to 800 GeV. In the present study we have extended our analysis by calculating the moments using the Tsallis model at these fixed target experiment data. By using the Tsallis model we have also calculated the average charged multiplicity and its dependence on energy. It is found that the average charged multiplicity and moments predicted by the Tsallis statistics are in much agreement with the experimental values and indicates the success of the Tsallis model on data from visual detectors. The study of moments also illustrates that KNO scaling hypothesis holds good at these energies.

    hep-phnucl-thIJMPE(2020)·2 citations
24. 24*

    Characters and Group Invariant Polynomials of (Super)fields: Road to "Lagrangian"

    Upalaparna Banerjee🇮🇳 · Joydeep Chakrabortty🇮🇳 · Suraj Prakash🇮🇳 · Shakeel Ur Rahaman🇮🇳

    The dynamics of the subatomic fundamental particles, represented by quantum fields, and their interactions are determined uniquely by the assigned transformation properties, i.e., the quantum numbers associated with the underlying symmetry of the model. These fields constitute a finite number of group invariant operators which are assembled to build a polynomial, known as the Lagrangian. The order of the polynomial is determined by the mass dimension. In this paper, we have introduced a Mathematica package, GrIP, that computes the complete set of operators that form a basis at each such order for a model containing any number of fields transforming under connected compact groups. The spacetime symmetry is restricted to the Lorentz group. The first part of the paper is dedicated to formulating the algorithm of GrIP. In this context, the detailed and explicit construction of the characters of different representations corresponding to connected compact groups and respective Haar measures have been discussed in terms of the coordinates of their respective maximal torus. In the second part, we have documented the user manual of GrIP that captures the generic features and guides to prepare the input file. This program works very efficiently to find out the higher mass (non-supersymmetric) and canonical (supersymmetric) dimensional operators relevant to the Effective Field Theory. We have demonstrated the working principles with two examples:- the SM and the MSSM. We have further highlighted important features of GrIP, e.g., identification of effective operators leading to specific rare processes linked with the violation of baryon and lepton numbers, using several BSM scenarios. We have also tabulated a complete set of dimension-6 operators for each such model. Some of the operators possess rich flavour structures which are discussed in detail. This work paves the way towards BSM-EFT.

    hep-phhep-thEPJC(2020)·38 citations
25. 25*

    Charm-meson Triangle Singularity in $e^{+}{e}^{-}$ Annihilation into $D^{\ast 0}{\bar{D}}^0+\gamma$

    Eric Braaten🇺🇸 · Li-Ping He🇺🇸 · Kevin Ingles🇺🇸 · Jun Jiang🇨🇳

    We calculate the cross section for $e^{+}{e}^{-}$ annihilation into $D^{\ast 0}{\bar{D}}^0+\gamma$ at center-of-mass energies near the $D^{\ast 0}{\bar{D}}^{\ast 0}$ threshold under the assumption that $X(3872)$ is a weakly bound charm meson molecule. The Dalitz plot has a ${\bar{D}}^{\ast 0}$ resonance band in the squared invariant mass $t$ of ${\bar{D}}^0\gamma$. In the limit as the decay width of the $D^{\ast 0}$ goes to 0, the Dalitz plot also has a narrow band in the squared invariant mass $u$ of $D^{\ast 0}{\bar{D}}^0$ from a charm-meson triangle singularity. At the physical value of the $D^{\ast 0}$ width, the narrow band reduces to a shoulder. Thus the triangle singularity cannot be observed directly as a peak in a differential cross section as a function of $u$. It may however be observed indirectly as a local minimum in the $t$ distribution for events with $u$ below the triangle singularity. The minimum is produced by the Schmid cancellation between triangle loop diagrams and a tree diagram. The observation of this minimum would support the identification of $X(3872)$ as a weakly bound charm meson molecule.

    hep-phPRD(2020)·28 citations
26. 26*

    Dissociation of heavy quarkonia in a weak magnetic field

    Mujeeb Hasan🇮🇳 · Binoy Krishna Patra🇮🇳

    We examined the effects of the weak magnetic field on the dissociation of heavy quarkonia immersed in a thermal medium of quarks and gluons. For that purpose, we have revisited the general structure of gluon self-energy tensor in the presence of a weak magnetic field in thermal medium and obtained the relevant structure functions. The structure functions give the real and imaginary parts of the resummed gluon propagator, which further give the respective dielectric permittivities. The real and imaginary parts of the dielectric permittivity will be used to evaluate the real and imaginary parts of the complex heavy quark potential. The real-part of the potential is found to be more screened, whereas the magnitude of the imaginary-part of the potential gets increased on increasing the value of both temperature and magnetic field. In addition to this, we have observed that the real-part gets slightly more screened while the imaginary part gets increased in the presence of a weak magnetic field as compared to their counterparts in the absence of a magnetic field. The increase in the screening of the real-part of the potential leads to the decrease of binding energies of $J/\Psi$ and ${\rm Y}$, whereas the increase in the magnitude of the imaginary part leads to the increase of thermal width with the temperature and magnetic field both. Also the binding energy and thermal width in the presence of weak magnetic field become smaller and larger, respectively, as compared to that in the pure thermal case. We have finally obtained the dissociation temperatures for $J/\Psi$ and ${\rm Y}$, which become slightly lower in the presence of weak magnetic field. This observation leads to the slightly early dissociation of quarkonia because of the presence of a weak magnetic field.

    hep-phPRD(2020)·37 citations
27. 27*

    Perturbative unitarity bounds for fermions composite models

    Simone Biondini🇳🇱

    Perturbative unitarity is a powerful tool for inferring the range of validity of a given effective field theory. Here, we study such a bound in the parameter space of dimension-5 and dimension-6 effective operators that arise in a scenario of fermion compositeness. These operators are routinely used in experimental searches at the LHC to constraint contact and gauge interactions between ordinary Standard Model fermions and excited states of mass $M$. We derive the unitarity bound for the production process of an excited neutrino, then we implement such bound and compare it with the recent experimental exclusion curves for Run 2, the High-Luminosity and High-Energy configurations of the LHC. The results also apply to the searches where a generic single excited state is produced via dimension-6 contact interactions. The unitarity bound, so far overlooked in these effective models, is quite compelling and can serve as a guide for exploring the parameter space ($M,\Lambda$) in addition to the standard request $M\le \Lambda$.

    hep-phPoS(2020)·0 citations
28. 28*

    Seesaw neutrino dark matter by freeze-out

    Carlos Jaramillo🇩🇪 · Manfred Lindner🇩🇪 · Werner Rodejohann🇩🇪

    We investigate whether right-handed neutrinos can play the role of the dark matter of the Universe and be generated by the freeze-out production mechanism. In the standard picture, the requirement of a long lifetime of the right-handed neutrinos implies a small neutrino Yukawa coupling. As a consequence, they never reach thermal equilibrium, thus prohibiting production by freeze-out. We note that this limitation is alleviated if the neutrino Yukawa coupling is large enough in the early Universe to thermalize the sterile neutrinos, and then becomes tiny at a certain moment, which makes them drop out of equilibrium. As a concrete example realization of this framework, we consider a Froggatt-Nielsen model supplemented by an additional scalar field which obeys a global symmetry (not the flavour symmetry). Initially, the vacuum expectation value of the flavon is such, that the effective neutrino Yukawa coupling is large and unsuppressed, keeping them in thermal equilibrium. At some point the new scalar also gets a vacuum expectation value that breaks the symmetry. This may occur in such a way that the vev of the flavon is shifted to a new (smaller) value. In that case, the Yukawa coupling is reduced such that the sterile neutrinos are rendered stable on cosmological time scales. We show that this mechanism works for a wide range of sterile neutrino masses.

    hep-phJCAP(2021)·11 citations
29. 29*

    What is the Top Quark Mass?

    André H. Hoang🇦🇹

    In this review I give an overview on the conceptual issues involved in the question how to interpret so-called `direct top quark mass measurements', which are based on the kinematic reconstruction of top quark decay products at the Large Hadron Collider (LHC). These measurements quote the top mass parameter $m_t^{\mathrm{MC}}$ of Monte-Carlo event generators with current uncertainties of around $0.5$ GeV. At present time the problem of finding a rigorous relation between $m_t^{\mathrm{MC}}$ and top mass renormalization schemes defined in field theory is unresolved and touches perturbative as well as nonperturbative aspects and the limitations of state-of-the-art Monte-Carlo event generators. I review the status of LHC top mass measurements, illustrate how conceptual limitations enter and explain a controversy that has permeated the community in the context of the interpretation problem. Recent advances in acquiring first principle insights are summarized, and it is outlined what else has to be understood to fully resolve the issue. For the time being, I give a recommendation how to deal with the interpretation problem when making top mass dependent theoretical predictions.

    hep-phhep-exAnn.Rev.Nucl.Part.Sci.(2020)·142 citations
30. 30*

    New Insights on Lepton Number and Dark Matter

    Ernest Ma (UC Riverside)🇺🇸

    Dark matter (DM) is usually assumed to be stabilized by a symmetry, which is mostly considered to be $Z_2$. For example, in supersymmetry it is $R$ parity, i.e. $(-1{)}^{3B+L+2j}$. However, it may be $Z_n$ or $U(1{)}_D$, and derivable from generalized lepton number. In this context, neutrinos may be Majorana or Dirac, and owe their masses to dark matter, i.e. they are scotogenic.

    hep-ph3 citations
31. 31*

    The locally monochromatic approximation to QED in intense laser fields

    T. Heinzl🇬🇧 · B. King🇬🇧 · A. J. MacLeod🇬🇧

    We derive an approximation to QED effects in strong background fields which can be employed to improve numerical simulations of laser-particle collisions. Treating the laser as a plane wave of arbitrary intensity, we split the wave into fast (carrier) and slow (envelope) modes. We solve the interaction dynamics exactly for the former while performing a local expansion in the latter. This yields a `locally monochromatic' approximation (LMA), which we compare with exact spectra for nonlinear Compton scattering and nonlinear Breit-Wheeler pair production, for realistic laser pulse durations. We show that, as an improvement over the commonly used `locally-constant field' approximation, the LMA exactly reproduces the correct low energy behaviour of particle spectra, as well as the position and amplitude of harmonic features.

    hep-phphysics.opticsphysics.plasm-phPRA(2020)·87 citations
32. 32*

    The Hubble tension and a renormalizable model of gauged neutrino self-interactions

    Maximilian Berbig🇩🇪 · Sudip Jana🇩🇪 · Andreas Trautner🇩🇪

    We present a simple extension of the Standard Model that leads to renormalizable long-range vector-mediated neutrino self-interactions. This model can resolve the Hubble tension by delaying the onset of neutrino free-streaming during recombination, without conflicting with other measurements. The extended gauge, scalar and neutrino sectors lead to observable signatures, including invisible Higgs and $Z$ decays, thereby relating the Hubble tension to precision measurements at the LHC and future colliders. The model has a new neutrinophilic gauge boson with $m_{Z^{\prime }}\sim \mathcal{O}(10\mathrm{eV})$ and charged Higgses at a few $100\mathrm{GeV}$. It requires hidden neutrinos with active-hidden mixing angles larger than $5\times 10^{-4}$ and masses in the range $1÷300\mathrm{eV}$, which could also play a role for short baseline neutrino oscillation anomalies.

    hep-phastro-ph.COhep-exPRD(2020)·86 citations
33. 33*

    Single spin asymmetry $A_{UL}^{\sin (2{\varphi }_h-2{\varphi }_R)}$ in dihadron semi-inclusive DIS

    Xuan Luo🇨🇳 · Hao Sun🇨🇳

    The single longitudinal spin asymmetry $A_{UL}^{\sin (2{\varphi }_h-2{\varphi }_R)}$ of dihadron production in semi-inclusive deep inelastic scattering (SIDIS) is examined through helicity-dependent dihadron fragmentation function (DiFF) $G_1^{\perp }$. The correlation of the longitudinal polarization of a fragmenting quark with the transverse momenta of the produced hadron pair is illustrated by this DiFF. The experimental investigation for this azimuthal asymmetry in dihadron SIDIS by the COMPASS Collaboration has lately yielded a very small signal. Here, the unknown T-odd dihadron fragmentation function $G_1^{\perp }$ utilizing a spectator model is computed. The model has been successfully used to describe the dihadron production in both the unpolarized and the single polarized processes to access the asymmetry and clarify why the signal is very small. The transverse momentum dependent factorization method, in which the transverse momentum of the final state hadron pair is left unintegrated, has been considered. The $\sin (2{\varphi }_h-2{\varphi }_R)$ asymmetry at the COMPASS kinematics is estimated and we compare it with the data. Besides, the predictions on the same asymmetry are also made at the HERMES and Electron Ion Collider.

    hep-phPRD(2020)·5 citations
34. 34*

    Kotzinian-Mulders effect in semi-inclusive DIS within TMD factorization

    Xuan Luo🇨🇳 · Hao Sun🇨🇳

    In this paper we study the Kotzinian-Mulders effect of a single hadron production in semi-inclusive deep inelastic scattering (SIDIS) within the framework of transverse momentum dependent (TMD) factorization. The asymmetry is contributed by the convolution of the Kotzinian-Mulders function $g_{1T}$ and the unpolarized fragmentation function $D_1$. As a TMD distribution, the Kotzinian-Mulders function in the coordinate space in the perturbative region can be represented as the convolution of the $C$-coefficients and the corresponding collinear correlation function. The Wandzura-Wilczek approximation is used to obtain this correlation function. We perform a detailed phenomenological numerical analysis of the Kotzinian-Mulders effect in the SIDIS process within TMD factorization at the kinematics of the HERMES and COMPASS measurements. It is found that the obtained $x_B$-, $z_h$- and $P_{h\perp }$-dependent Kotzinian-Mulders effect are basically consistent with the HERMES and COMPASS measurements.

    hep-phCPC(2022)·1 citation
35. 35*

    Drag force on a moving heavy quark with deformed string configuration

    Sara Tahery🇨🇳 · Xurong Chen🇨🇳

    To study drag force on a moving heavy quark through a plasma, we use a deformed AdS space-time, in which deformation parameter $c$ describes non-conformality in AdS/QCD. In this case the quark is mapped to a probe string in the AdS space. Considering probable contribution of deformation parameter in the probe string, we apply a general form of c-dependent string ansatz in the drag force computation. Then we find the acceptable value of this parameter as it satisfies QCD calculations. Using this result, we also discuss diffusion constant which is in agreement with phenomenological result for non-relativistic limit. Also we show that while in absence of deformation parameter, probe string is a strictly increasing function of radial coordinate, the c-dependent probe string has a maximum value versus $z$.

    ↳ hep-thhep-phCommun.Theor.Phys.(2022)·5 citations
36. 36*

    Modified Structure of Protons and Neutrons in Correlated Pairs

    B. Schmookler · M. Duer · A. Schmidt · O. Hen · S. Gilad · E. Piasetzky · M. Strikman · L.B. Weinstein · The CLAS Collaboration

    The atomic nucleus is made of protons and neutrons (nucleons), that are themselves composed of quarks and gluons. Understanding how the quark-gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding nucleons is an outstanding challenge. Although evidence for such modification, known as the EMC effect, was first observed over 35 years ago, there is still no generally accepted explanation of its cause. Recent observations suggest that the EMC effect is related to close-proximity Short Range Correlated (SRC) nucleon pairs in nuclei. Here we report the first simultaneous, high-precision, measurements of the EMC effect and SRC abundances. We show that the EMC data can be explained by a universal modification of the structure of nucleons in neutron-proton (np) SRC pairs and present the first data-driven extraction of this universal modification function. This implies that, in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have its quark structure distorted.

    ↳ nucl-exhep-phnucl-thNature(2019)·198 citations
37. 37*

    Decoding the QCD critical behaviour in A+A collisions

    Nikolaos G. Antoniou🇬🇷 · Nikolaos Davis🇵🇱 · Fotios K. Diakonos🇬🇷 · Georgios Doultsinos🇬🇷 · Nikolaos Kalntis🇬🇷 · Alexandros Kanargias🇬🇷 · Athanasios S. Kapoyannis🇬🇷 · Vitalii Ozvenchuk🇵🇱 · Costas N. Papanicolas🇬🇷 · Andrzej Rybicki🇵🇱 · Efstathios Stiliaris🇬🇷

    In a systematic search for the QCD critical point in nuclear collisions, at the CERN SPS, it was found that intermittency measurements in the freeze-out state of central Si+Si collisions, at the maximum SPS energy, provide us with an indication of sizeable critical fluctuations. Also, rather recently, a weaker effect was traced in preliminary data of the Ar+Sc reaction for 10-20% most central collisions at (approximately) the same energy. However, the uncertainties in the analysis and the limitations of the experimental event statistics make the interpretation of the above measurements (NA49, NA61/SHINE) rather inconclusive, inviting for a further, phenomenological investigation with complementary tools and theoretical ideas. To this end, in the present work, we employ intermittency techniques within a model-independent analysis scheme (AMIAS), a novel method from Data Science [arXiv:1205.6505], in order to produce unbiased results for the parameters of the power-laws and in particular for the associated power-law exponent (intermittency index) ${\varphi }_2$. Using data-sets at different peripheralities, we also study the dependence of the ${\varphi }_2$-value on the number of wounded nucleons, in order to uncover the approach to the critical point. With these findings and the help of Ising-QCD partition function, the interpretation of SPS intermittency measurements and their links to the critical region, are discussed.

    ↳ nucl-thhep-phnucl-exNPA(2020)·10 citations
38. 38*

    Symmetry restoration and the gluon mass in the Landau gauge

    Camille Noûs · Urko Reinosa · Julien Serreau · Rodrigo Carmo Terin · Matthieu Tissier

    We investigate the generation of a gluon screening mass in Yang-Mills theory in the Landau gauge. We propose a gauge-fixing procedure where the Gribov ambiguity is overcome by summing over all Gribov copies with some weight function. This can be formulated in terms of a local field theory involving constrained, nonlinear sigma model fields. We show that a phenomenon of radiative symmetry restoration occurs in this theory, similar to what happens in the standard nonlinear sigma model in two dimensions. This results in a nonzero gluon screening mass, as seen in lattice simulations.

    ↳ hep-thhep-lathep-phnucl-thSciPost Phys.(2021)·17 citations
39. 39*

    Revisiting the Scalar Weak Gravity Conjecture

    Karim Benakli🇫🇷 · Carlo Branchina🇫🇷 · Gaëtan Lafforgue-Marmet🇫🇷

    We revisit the Scalar Weak Gravity Conjecture and investigate the possibility to impose that scalar interactions dominate over gravitational ones. More precisely, we look for consequences of assuming that, for leading scalar interactions, the corresponding gravitational contribution is sub-dominant in the non-relativistic limit. For a single massive scalar particle, this leads us to compare four-point self-interactions in different type of potentials. For axion-like particles, we retrieve the result of the Axion Weak Gravity Conjecture: the decay constant $f$ is bounded by the Planck mass, $f<M_{Pl}$. Similar bounds are obtained for exponential potentials. For quartic, power law and Starobinsky potentials, we exclude large trans-Planckian field excursions. We then discuss the case of moduli that determine the scalars masses. We retrieve the exponential dependence as requested by the Swampland Distance Conjecture. We also find extremal state masses with field dependence that reproduces both the Kaluza-Klein and winding modes behaviour. In particular cases, our constraints can be put in the form of the Refined de Sitter Conjecture.

    ↳ hep-thhep-phEPJC(2020)·35 citations
40. 40*

    Spontaneous scalarization of Gauss-Bonnet black holes surrounded by massive scalar fields

    Yan Peng🇨🇳

    For massless scalar fields, a relation ${\Delta }_n=\frac{\sqrt{3}}{2}\pi$ for $n\to \infty$ was observed in the scalar-Gauss-Bonnet theory. In the present paper, we extend the discussion by including a nonzero scalar field mass. For massive scalar fields, we show that the relation ${\Delta }_n=\frac{\sqrt{3}}{2}\pi$ for $n\to \infty$ still holds. We demonstrate this relation with both analytical and numerical methods. The analytical analysis implies that this relation may be a very universal behavior.

    ↳ gr-qchep-phhep-thPLB(2020)·13 citations
41. 41*

    Approximate Solutions to the Klein-Fock-Gordon Equation for the sum of Coulomb and Ring-Shaped like potentials

    Sh. M. Nagiyev🇦🇿 · A. I. Ahmadov🇦🇿 · V. A. Tarverdiyeva🇦🇿

    We consider the quantum mechanical problem of the motion of a spinless charged relativistic particle with mass$M$, described by the Klein-Fock-Gordon equation with equal scalar $S(\vec{r})$ and vector $V(\vec{r})$ Coulomb plus ring-shaped potentials. It is shown that the system under consideration has both a discrete at $\left|E\right|<M{c}^2$ and a continuous at $\left|E\right|>M{c}^2$ energy spectra. We find the analytical expressions for the corresponding complete wave functions. A dynamical symmetry group $SU(1,1)$ for the radial wave equation of motion is constructed. The algebra of generators of this group makes it possible to find energy spectra in a purely algebraic way. It is also shown that relativistic expressions for wave functions, energy spectra and group generators in the limit $c\to \infty$ go over into the corresponding expressions for the nonrelativistic problem.

    ↳ hep-thhep-phmath-phmath.MP+1Adv.High Energy Phys.(2020)·9 citations
42. 42*

    Schwinger production of scalar particles during and after inflation from the first principles

    O.O. Sobol🇨🇭 · E.V. Gorbar🇺🇦 · A.I. Momot🇺🇦 · S.I. Vilchinskii🇨🇭

    By using the first-principles approach, we derive a system of three quantum kinetic equations governing the production and evolution of charged scalar particles by an electric field in an expanding universe. Analyzing the ultraviolet asymptotic behavior of the kinetic functions, we found the divergent parts of the electric current and the energy-momentum tensor of the produced particles and determined the corresponding counterterms. The renormalized system of equations is used to study the generation of electromagnetic fields during and after inflation in the kinetic coupling model ${\mathcal{L}}_{\mathrm{EM}}=-(1/4)f^2(\varphi )F_{\mu \nu }{F}^{\mu \nu }$ with the Ratra coupling function $f=\exp (\beta \varphi /M_p)$. It is found that the electric current of created particles is retarded with respect to the electric field. This leads to an oscillatory behavior of both quantities in agreement with the results obtained previously in phenomenological kinetic and hydrodynamical approaches.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·18 citations
43. 43*

    Combined analysis of Planck and SPTPol data favors the early dark energy models

    Anton Chudaykin🇷🇺 · Dmitry Gorbunov🇷🇺 · Nikita Nedelko🇷🇺

    We study the implications of the Planck temperature power spectrum at low multipoles, $\ell <1000$, and SPTPol data. We show that this combination predicts consistent lensing-induced smoothing of acoustic peaks within $\Lambda$CDM cosmology and yields the robust predictions of the cosmological parameters. Combining only the Planck large-scale temperature data and the SPTPol polarization and lensing measurements within $\Lambda$CDM model we found substantially lower values of linear matter density perturbation ${\sigma }_8$ which bring the late-time parameter $S_8={\sigma }_8\sqrt{{\Omega }_m/0.3}=0.763\pm 0.022$ into accordance with galaxy clustering and weak lensing measurements. It also raises up the Hubble constant $H_0=69.68\pm 1.00\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ that reduces the Hubble tension to the $2.5\sigma$ level. We examine the residual tension in the Early Dark Energy (EDE) model which produces the brief energy injection prior to recombination. We implement both the background and perturbation evolutions of the scalar field which potential scales as $V(\varphi )\propto {\varphi }^{2n}$. Including cosmic shear measurements (KiDS, VIKING-450, DES) and local distance-ladder data (SH0ES) to the combined fit we found that EDE completely alleviates the Hubble tension while not degradating the fit to large-scale structure data. The EDE scenario significantly improves the goodness-of-fit by $2.9\sigma$ in comparison with the concordance $\Lambda$CDM model. The account for the intermediate-redshift data (the supernova dataset and baryon acoustic oscillation data) fits perfectly to our parameter predictions and indicates the preference of EDE over $\Lambda$CDM at $3\sigma$.

    ↳ astro-ph.COhep-phJCAP(2020)·93 citations
44. 44*

    Analytic constraints on the energy-momentum tensor in conformal field theories

    Cédric Lorcé🇫🇷 · Peter Lowdon🇫🇷

    In this work we investigate the matrix elements of the energy-momentum tensor for massless on-shell states in four-dimensional unitary, local, and Poincaré covariant quantum field theories. We demonstrate that these matrix elements can be parametrised in terms of covariant multipoles of the Lorentz generators, and that this gives rise to a form factor decomposition in which the helicity dependence of the states is factorised. Using this decomposition we go on to explore some of the consequences for conformal field theories, deriving the explicit analytic conditions imposed by conformal symmetry, and using examples to illustrate that they uniquely fix the form of the matrix elements. We also provide new insights into the constraints imposed by the existence of massless particles, showing in particular that massless free theories are necessarily conformal.

    ↳ hep-thgr-qchep-phPRD(2020)·4 citations
45. 45*

    Indirect detection of Cosmological Constant from interacting open quantum system

    Subhashish Banerjee🇮🇳 · Sayantan Choudhury🇩🇪 · Satyaki Chowdhury🇮🇳 · Rathindra Nath Das🇮🇳 · Nitin Gupta🇮🇳 · Sudhakar Panda🇮🇳 · Abinash Swain🇮🇳

    We study the indirect detection of Cosmological Constant from an open quantum system of interacting spins, weakly interacting with a thermal bath, a massless scalar field minimally coupled with the static de Sitter background, by computing the spectroscopic shifts. By assuming pairwise interaction between spins, we construct states using a generalisation of the superposition principle. The corresponding spectroscopic shifts, caused by the effective Hamiltonian of the system due to Casimir Polder interaction, are seen to play a crucial role in predicting a very tiny value of the Cosmological Constant, in the static patch of de Sitter space, which is consistent with the observed value from the Planck measurements of the cosmic microwave background (CMB) anisotropies.

    ↳ hep-thcond-mat.stat-mechgr-qchep-ph+1Annals Phys.(2022)·18 citations
46. 46*

    Geodesic Structure of the Quantum-Corrected Schwarzschild Black Hole Surrounded by Quintessence

    Kourosh Nozari🇮🇷 · Milad Hajebrahimi🇮🇷

    By considering the back-reaction of the spacetime through the spherically symmetric quantum fluctuations of the background metric, Kazakov and Solodukhin removed the singularity of the Schwarzschild black hole. This regular Schwarzschild black hole has a spherical central region with a radius of the order of the Planck length. On the other hand, due to the positively accelerating expansion of the Universe, it seems that there exists a universal repulsive force known as dark energy. In the framework of quantum field theories, the quintessence field is a candidate model for investigating and modeling dark energy. Accordingly, by taking into account the quintessential matter field in the background of the Schwarzschild black hole, Kiselev gained the metric of this black hole surrounded by quintessence. By combining these two above ideas, in the present study we consider the quantum-corrected Schwarzschild black hole surrounded by quintessence to investigate null and time-like geodesics structure. Generally, this study points out that black holes are quantum-gravitational objects. We will show that the accelerated expansion of the Universe, instead of dark energy, happens because of the presence of quantum effects in this setup. Also, due to the presence of the central Planck-size sphere, the regular black hole has been possessed a shifting over radial coordinate in its inner structure.

    ↳ gr-qchep-phInt.J.Geom.Meth.Mod.Phys.(2022)·32 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.