Wed·Feb 10, 2021Wednesday·February 10, 2021

1. 01*

   Charms of Strongly Interacting Conformal Gauge Mediation

   Gongjun Choi🇨🇳 · Tsutomu T. Yanagida🇨🇳 · Norimi Yokozaki🇨🇳

   By extending a previously proposed conformal gauge mediation model, we construct a gauge-mediated SUSY breaking (GMSB) model where a SUSY-breaking scale, a messenger mass, the $\mu$-parameter and the gravitino mass in a minimal supersymmetric (SUSY) Standard Model (MSSM) are all explained by a single mass scale, a R-symmetry breaking scale. We focus on a low scale SUSY-breaking scenario with the gravitino mass $m_{3/2}=\mathcal{O}(1)\mathrm{eV}$, which is free from the cosmological gravitino problem and relaxes the fine-tuning of the cosmological constant. Both the messenger and SUSY-breaking sectors are subject to a hidden strong dynamics with the conformality above the messenger mass threshold (and hence the name of the model "strongly interacting conformal gauge mediation"). In our model, the Higgs B-term is suppressed and a large $\tan \beta$ is predicted, resulting in the relatively light second CP-even Higgs and the CP-odd Higgs with a sizable production cross section. These Higgs bosons can be tested at future LHC experiments.

   hep-phhep-thJHEP(2021)·1 citation
2. 02*

   Leptogenesis in an extended seesaw model with $U(1{)}_{B-L}$ symmetry

   Ujjal Kumar Dey🇮🇳 · Tapoja Jha🇮🇳 · Ananya Mukherjee🇮🇳 · Nirakar Sahoo🇮🇳

   We have explored an extended seesaw model accommodating a keV sterile neutrino adopting $U(1{)}_{B-L}$ symmetry. This model provides a natural platform for achieving resonant leptogenesis to account for the observed baryon asymmetry of the Universe. The required lepton asymmetry is sourced by the CP violating decay of the lightest heavy right handed neutrino to Standard Model leptons and Higgs. The presence of the light sterile neutrino in the model brings out an enhancement in the final lepton asymmetry through an additional self-energy contribution. Adopting a proper treatment for all the washout processes this framework strictly favors a strong washout regime thereby protecting the low energy neutrino mass parameters in agreement with the present neutrino and cosmology data. This framework of extended seesaw scheme offers the source of matter-antimatter asymmetry without any severe fine tuning of the Yukawa couplings governing the tiny neutrino mass. We also comment on the half-life period for the neutrino less double beta decay process in the background of having a keV sterile neutrino satisfying all the constraints which guide the explanation for the observed baryon asymmetry of the Universe.

   hep-phJ.Phys.G(2023)·5 citations
3. 03*

   Supernova Constraint on Self-Interacting Dark Sector Particles

   Allan Sung🇹🇼 · Gang Guo🇹🇼 · Meng-Ru Wu🇹🇼

   We examine the constraints on sub-GeV dark sector particles set by the proto-neutron star cooling associated with the core-collapse supernova event SN1987a. Considering explicitly a dark photon portal dark sector model, we compute the relevant interaction rates of dark photon ($A^{\prime }$) and dark fermion ($\chi$) with the Standard Model particles as well as their self-interaction inside the dark sector. We find that even with a small dark sector fine structure constant ${\alpha }_D\ll 1$, dark sector self-interactions can easily lead to their own self-trapping. This effect strongly limits the energy luminosity carried away by dark sector particles from the supernova core and thus drastically affects the parameter space that can be constrained by SN1987a. We consider specifically two mass ratios $m_{A^{\prime }}=3m_{\chi }$ and $3m_{A^{\prime }}=m_{\chi }$ which represent scenarios where the decay of $A^{\prime }$ to $\chi \bar{\chi }$ is allowed or not. We show that SN1987a can only place bounds on the dark sector when ${\alpha }_D\lesssim 10^{-15}$ ($10^{-7}$) for the former (latter) for $m_{\chi }\lesssim 20$ MeV. Furthermore, this evades the supernova bounds on the widely-examined dark photon parameter space completely if ${\alpha }_D\lesssim 10^{-7}$ for the former, while lifts the bounds when ${\alpha }_D\lesssim 10^{-7}$ if $m_{\chi }\lesssim 100$ MeV. Our findings thus imply that the existing supernova bounds on light dark particles can be generally evaded by a similar self-trapping mechanism. This also implies that non-standard strongly self-interacting neutrino is not consistent with the SN1987a observation. Same effects can also take place for other known stellar bounds on dark sector particles.

   hep-phastro-ph.HEPRD(2021)·33 citations
4. 04*

   Minimal scenario of Criticality for Electroweak scale, Neutrino Masses, Dark Matter, and Inflation

   Yuta Hamada🇺🇸 · Hikaru Kawai🇯🇵 · Kiyoharu Kawana🇰🇷 · Kin-ya Oda🇯🇵 · Kei Yagyu🇯🇵

   We propose a minimal model that can explain the electroweak scale, neutrino masses, Dark Matter (DM), and successful inflation all at once based on the multicritical-point principle (MPP). The model has two singlet scalar fields that realize an analogue of the Coleman-Weinberg mechanism, in addition to the Standard Model with heavy Majorana right-handed neutrinos. By assuming a $Z_2$ symmetry, one of the scalars becomes a DM candidate whose property is almost the same as the minimal Higgs-portal scalar DM. In this model, the MPP can naturally realize a saddle point in the Higgs potential at high energy scales. By the renormalization-group analysis, we study the critical Higgs inflation with non-minimal coupling $\xi |H{|}^{2}R$ that utilizes the saddle point of the Higgs potential. We find that it is possible to realize successful inflation even for $\xi =25$ and that the heaviest right-handed neutrino is predicted to have a mass around $10^{14}$ GeV to meet the current cosmological observations. Such a small value of $\xi$ can be realized by the Higgs-portal coupling ${\lambda }_{SH}\simeq 0.32$ and the vacuum expectation value of the additional neutral scalar $⟨\varphi ⟩\simeq 2.7$ TeV, which correspond to the dark matter mass 2.0 TeV, its spin-independent cross section $1.8\times 10^{-9}$ pb, and the mass of additional neutral scalar 190 GeV.

   hep-phgr-qcEPJC(2021)·15 citations
5. 05*

   The New Charm-Strange Resonances in the D^- K^+ Channel

   R.M. Albuquerque🇧🇷 · S. Narison🇫🇷 · D. Rabetiarivony🇲🇬 · G. Randriamanatrika🇲🇬

   We evaluate the masses and decay constants of the $0^{+}$ and $1^{-}$ open-charm $(\bar{c}\bar{d})(us)$ tetraquarks and molecular states from QCD spectral sum rules (QSSR) by using QCD Laplace sum rule (LSR). This method takes into account the stability criteria where the factorized perturbative NLO corrections and the contributions of quark and gluon condensates up to dimension-6 in the OPE are included. We confront our results with the $D^{-}{K}^{+}$ invariant mass recently reported by LHCb from $B^{+}\to D^{+}(D^{-}{K}^{+})$ decays. We expect that the resonance near the $D^{-}{K}^{+}$ threshold can be originated from the $0^{+}(D^{-}{K}^{+})$ molecule and/or $D^{-}{K}^{+}$ scattering. The $X_0(2900)$ scalar state and the resonance $X_J(3150)$ (if $J=0$) can emerge from a minimal mixing model, with a tiny mixing angle ${\theta }_0\simeq (5.2\pm 1.9{)}^0$, between a scalar Tetramole $({\mathcal{T}}_{\mathcal{M}0})$ (superposition of nearly degenerated hypothetical molecules and compact tetraquarks states with the same quantum numbers), having a mass $M_{{\mathcal{T}}_{\mathcal{M}0}}=2743(18)$ MeV, and the first radial excitation of the $D^{-}{K}^{+}$ molecule with mass $M_{(DK{)}_1}=3678(310)$ MeV. In an analogous way, the $X_1(2900)$ and the $X_J(3350)$ (if $J=1$) could be a mixture between the vector Tetramole $({\mathcal{T}}_{\mathcal{M}1})$, with a mass $M_{{\mathcal{T}}_{\mathcal{M}1}}=2656(20)$ MeV, and its first radial excitation having a mass $M_{{\mathcal{T}}_{\mathcal{M}1}}=4592(141)$ MeV with an angle ${\theta }_0\simeq (9.1\pm 0.6{)}^0$. A (non)-confirmation of these statements requires experimental findings of the quantum numbers of the resonances at $3150$ and $3350$ MeV.

   hep-phhep-exhep-thNucl.Part.Phys.Proc.(2021)·6 citations
6. 06*

   Axion induced spin effective couplings

   Zihang Wang🇨🇳 · Lijing Shao🇨🇳

   Detecting axionic dark matter induced electron or nucleon oscillating electric dipole moment (OEDM) has become a new way for dark matter searches. We re-examine such axion-spin couplings in external electromagnetic fields. We point out that axion-photon interaction induces an electron spin effective coupling, which is different from an OEDM. In particular, the axion-spin effective coupling is directly related to magnetic field rather than electric field. For axion-electron or axion-nucleon couplings, an OEDM of fermion is introduced, whose effect in ultralight axion cases depends on whether axion shift symmetry is manifest. Specifically, ultralight axionic dark matter interactions that do not obey the shift symmetry will be strongly constrained. We also extend the results to the case where axion has a finite velocity.

   hep-phPRD(2021)·14 citations
7. 07*

   The role of $D_{(s)}^{\ast }$ and their contributions in $B_{(s)}\to D_{(s)}h{h}^{\prime }$ decays

   Jian Chai🇨🇳 · Shan Cheng🇨🇳 · Wen-Fei Wang🇨🇳

   We demonstrate the roles of $D_{(s)}^{\ast }$ and their contributions in the quasi-two-body decays $B_{(s)}\to D_{(s)}h{h}^{\prime }$ ($h,h^{\prime }=\{\pi ,K\}$) in the perturbative QCD approach, stemming from the quark flavour changing $\bar{b}\to \bar{c}{q}_2{\bar{q}}_1$ and $\bar{b}\to c\overline{q_1}\overline{q_2}$ with $q_1,q_2=\{s/d,u\}$. The main motivation of this study is the measurements of significant derivations from the simple phase-space model in the channels $B_{(s)}\to D_{(s)}h{h}^{\prime }$ at $B$ factories and LHC, which is now clarified as the Breit-Wigner-tail effects from the corresponding intermediate resonant states $D_{(s)}^{\ast }$. We confirm that these effect from $D^{\ast }$ is small ($\sim 5\%$) in the quasi-two-body $B_{(s)}\to D\pi \pi (K)$ decaying channels, and predict the tiny ($<1\%$) contributions from $D^{\ast }$ in the $B_{(s)}\to D_{s}K\pi (K)$ decaying channels, our result for the $B_s\to DK\pi (K)$ decaying channels contributed only from the Breit-Wigner-tail effect of $D_s^{\ast }$ is in agreement with the current LHCb measurement. We recommend the Belle-II and the LHCb collaborations to restudy the processes $B^{+}\to {\bar{D}}^{\ast 0}{\pi }^{+}(K^{+})\to D^{-}{\pi }^{+}{\pi }^{+}(K^{+})$ to reveal the structure of $D^{\ast 0}$ and the strong decay $D^{\ast 0}\to D^{+}{\pi }^{-}$.

   hep-phPRD(2021)·11 citations
8. 08*

   Constraints on electromagnetic form factors of sub-GeV dark matter from the Cosmic Microwave Background anisotropy

   Gaetano Lambiase🇮🇹 · Subhendra Mohanty🇮🇳 · Akhilesh Nautiyal🇮🇳 · Soumya Rao🇮🇳

   We consider dark matter which have non-zero electromagnetic form factors like electric/magnetic dipole moments and anapole moment for fermionic dark matter and Rayleigh form factor for scalar dark matter. We consider dark matter mass $m_{\chi }>\mathcal{O}(\mathrm{MeV})$ and put constraints on their mass and electromagnetic couplings from CMB and LSS observations. Fermionic dark matter with non-zero electromagnetic form factors can annihilate to $e^{+}{e}^{-}$ and scalar dark matter can annihilate to $2\gamma$ at the time of recombination and distort the CMB. We analyze dark matter with multipole moments with Planck and BAO observations. We find upper bounds on anapole moment $g_A<7.163\times 10^3{\text{GeV}}^{-2}$, electric dipole moment $\mathcal{D}<7.978\times 10^{-9}\text{e-cm}$, magnetic dipole moment $\mu <2.959\times 10^{-7}{\mu }_B$, and the bound on Rayleigh form factor of dark matter is $g_4/{\Lambda }_4^2<1.085\times 10^{-2}{\text{GeV}}^{-2}$ with $95\%$C.L.

   hep-phastro-ph.COPRD(2021)·8 citations
9. 09*

   Physical limits in the Color Dipole Model Bounds

   G.R.Boroun🇮🇷

   The ratio of the cross sections for the transversely and longitudinally virtual photon polarizations, ${\sigma }_{L/T}^{{\gamma }^{\ast }p}$, at high photon-hadron energy scattering is studied. I investigate the relationship between the gluon distribution obtained using the color dipole model and standard gluons obtained from the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution and the Altarelli-Martinelli equations. It is shown that the color dipole bounds are dependent on the gluon distribution behavior. This behavior is considered by the expansion and Laplace transform methods. Numerical calculations and comparison with the color dipole model (CDM) bounds can indicate the range of validity of this method at small dipole sizes, $r\sim 1/Q\ll 1/Q_s$.

   hep-phEPJA(2021)·7 citations
10. 10*

    Radiative Decays of Charged Leptons in the Seesaw Effective Field Theory with One-loop Matching

    Di Zhang🇨🇳 · Shun Zhou🇨🇳

    The canonical type-I seesaw model with three heavy Majorana neutrinos is one of the most natural extensions of the standard model (SM) to accommodate tiny Majorana masses of three ordinary neutrinos. At low-energy scales, Majorana neutrino masses and unitarity violation of lepton flavor mixing have been extensively discussed in the literature, which are respectively generated by the unique dimension-five Weinberg operator and one dimension-six operator in the seesaw effective field theory (SEFT) with the tree-level matching. In this work, we clarify that a self-consistent calculation of radiative decays of charged leptons ${\beta }^{-}\to {\alpha }^{-}+\gamma$ requires the SEFT with one-loop matching, where new six-dimensional operators emerge and make important contributions. For the first time, the Wilson coefficients of all the relevant six-dimensional operators are computed by carrying out the one-loop matching between the effective theory and full seesaw model, and applied to calculate the total rates of radiative decays of charged leptons.

    hep-phhep-exPLB(2021)·23 citations
11. 11*

    Infrared facets of the three-gluon vertex

    A. C. Aguilar🇧🇷 · F. De Soto🇪🇸 · M. N. Ferreira🇧🇷 · J. Papavassiliou🇪🇸 · J. Rodríguez-Quintero🇪🇸

    We present novel lattice results for the form factors of the quenched three-gluon vertex of QCD, in two special kinematic configurations that depend on a single momentum scale. We consider three form factors, two associated with a classical tensor structure and one without tree-level counterpart, exhibiting markedly different infrared behaviors. Specifically, while the former display the typical suppression driven by a negative logarithmic singularity at the origin, the latter saturates at a small negative constant. These exceptional features are analyzed within the Schwinger-Dyson framework, with the aid of special relations obtained from the Slavnov-Taylor identities of the theory. The emerging picture of the underlying dynamics is thoroughly corroborated by the lattice results, both qualitatively as well as quantitatively.

    hep-phhep-lathep-thPLB(2021)·47 citations
12. 12*

    Global Searches for New Physics with Top Quarks

    Susanne Westhoff🇩🇪

    This is a brief summary of the latest searches for virtual effects of new physics in the top sector. In the framework of the Standard Model Effective Field Theory (SMEFT), I show how to resolve the structure of effective couplings by combining observables at the LHC and at flavor experiments in a global fit. With this approach we start exploring the features of a UV theory at energies beyond current colliders.

    hep-phhep-ex0 citations
13. 13*

    Explaining the MiniBooNE Anomalous Excess via Leptophilic ALP-Sterile Neutrino Coupling

    Chia-Hung Vincent Chang🇹🇼 · Chuan-Ren Chen🇹🇼 · Shu-Yu Ho🇰🇷 · Shih-Yen Tseng🇯🇵

    Recently, the MiniBooNE experiment at Fermilab has updated the results with increased data and reported an excess of $560.6\pm 119.6$ electronlike events ($4.7\sigma$) in the neutrino operation mode. In this paper, we propose a scenario to account for the excess where a Dirac-type sterile neutrino, produced by a charged kaon decay through the neutrino mixing, decays into a leptophilic axionlike particle ($\ell$ALP) and a muon neutrino. The electron-positron pairs produced from the $\ell$ALP decays can be interpreted as electronlike events provided that their opening angle is sufficiently small. In our framework, we consider the $\ell$ALP with a mass $m_a^{}=20\text{MeV}$ and an inverse decay constant $c_e^{}/f_a^{}=10^{-2}{\text{GeV}}^{-1}$, allowed by the astrophysical and experimental constraints. Then, after integrating the predicted angular or visible energy spectra of the $\ell$ALP to obtain the total excess event number, we find that our scenario with sterile neutrino masses within $150\text{MeV}\lesssim m_N^{}\lesssim 380\text{MeV}$ ($150\text{MeV}\lesssim m_N^{}\lesssim 180\text{MeV}$) and neutrino mixing parameters between $10^{-10}\lesssim |U_{\mu 4}{|}^2\lesssim 10^{-8}$ ($3\times 10^{-7}\lesssim |U_{\mu 4}{|}^2\lesssim 8\times 10^{-7}$) can explain the MiniBooNE data.

    hep-phPRD(2021)·37 citations
14. 14*

    Top-pair production via gluon fusion in the Standard Model Effective Field Theory

    Christoph Müller🇩🇪

    We compute the leading corrections to the differential cross section for top-pair production via gluon fusion due to dimension-six operators at leading order in QCD. The Standard Model fields are assumed to couple only weakly to the hypothetical new sector. A systematic approach then suggests treating single insertions of the operator class containing gluon field strength tensors on the same footing as expli\-citly loop suppressed contributions from four-fermion operators. This is in particular the case for the chromomagnetic operator $Q_{(uG)}$ and the purely bosonic operators $Q_{(G)}$ and $Q_{(\phi G)}$. All leading order dimension-six contributions are consequently suppressed with a loop factor $1/16{\pi }^2$.

    hep-phPRD(2021)·7 citations
15. 15*

    Simulating collider physics on quantum computers using effective field theories

    Christian W. Bauer🇺🇸 · Marat Freytsis🇺🇸 · Benjamin Nachman🇺🇸

    Simulating the full dynamics of a quantum field theory over a wide range of energies requires exceptionally large quantum computing resources. Yet for many observables in particle physics, perturbative techniques are sufficient to accurately model all but a constrained range of energies within the validity of the theory. We demonstrate that effective field theories (EFTs) provide an efficient mechanism to separate the high energy dynamics that is easily calculated by traditional perturbation theory from the dynamics at low energy and show how quantum algorithms can be used to simulate the dynamics of the low energy EFT from first principles. As an explicit example we calculate the expectation values of vacuum-to-vacuum and vacuum-to-one-particle transitions in the presence of a time-ordered product of two Wilson lines in scalar field theory, an object closely related to those arising in EFTs of the Standard Model of particle physics. Calculations are performed using simulations of a quantum computer as well as measurements using the IBMQ Manhattan machine.

    hep-phhep-latquant-phPRL(2021)·94 citations
16. 16*

    Loop-tree duality from vertices and edges

    William J. Torres Bobadilla🇩🇪

    The causal representation of multi-loop scattering amplitudes, obtained from the application of the loop-tree duality formalism, comprehensively elucidates, at integrand level, the behaviour of only physical singularities. This representation is found to manifest compact expressions for multi-loop topologies that have the same number of \textit{vertices}. Interestingly, integrands considered in former studies, with up-to six vertices and $L$ internal lines, display the same structure of up-to four-loop ones. The former is an insight that there should be a correspondence between vertices and the collection of internal lines, \textit{edges}, that characterise a multi-loop topology. By virtue of this relation, in this paper, we embrace an approach to properly classify multi-loop topologies according to vertices and edges. Differently from former studies, we consider the most general topologies, by connecting vertices and edges in all possible ways. Likewise, we provide a procedure to generate causal representation of multi-loop topologies by considering the structure of causal propagators. Explicit causal representations of loop topologies with up-to nine vertices are provided.

    hep-phhep-thJHEP(2021)·50 citations
17. 17*

    Exact accidental U(1) symmetries for the axion

    Luc Darmé🇮🇹 · Enrico Nardi🇮🇹

    We study a class of gauge groups that can automatically yield a perturbatively exact Peccei-Quinn symmetry, and we outline a model in which the axion quality problem is solved at all operator dimensions. Gauge groups belonging to this class can also enforce and protect accidental symmetries of the clockwork type, and we present a toy model where an `invisible' axion arises from a single breaking of the gauge and global symmetries.

    hep-phhep-thPRD(2021)·23 citations
18. 18*

    Geometrical approach to causality in multi-loop amplitudes

    German F. R. Sborlini🇩🇪

    An impressive effort is being placed in order to develop new strategies that allow an efficient computation of multi-loop multi-leg Feynman integrals and scattering amplitudes, with a particular emphasis on removing spurious singularities and numerical instabilities. In this article, we describe an innovative geometric approach based on graph theory to unveil the causal structure of any multi-loop multi-leg amplitude in Quantum Field Theory. Our purely geometric construction reproduces faithfully the manifestly causal integrand-level behaviour of the Loop-Tree Duality representation. We found that the causal structure is fully determined by the vertex matrix, through a suitable definition of connected partitions of the underlying diagrams. Causal representations for a given topological family are obtained by summing over subsets of all the possible causal entangled thresholds that originate connected and oriented partitions of the underlying topology. These results are compatible with Cutkosky rules. Moreover, we found that diagrams with the same number of vertices and multi-edges exhibit similar causal structures, regardless of the number of loops.

    hep-phhep-thPRD(2021)·55 citations
19. 19*

    Exploring the new physics phases in 3+1 scenario in neutrino oscillation experiments

    Nishat Fiza🇮🇳 · Mehedi Masud🇰🇷 · Manimala Mitra🇮🇳

    The various global analyses of available neutrino oscillation data indicate the presence of the standard $3+0$ neutrino oscillation picture. However, there are a few short baseline anomalies that point to the possible existence of a fourth neutrino (with mass in the eV-scale), essentially sterile in nature. Should sterile neutrino exist in nature and its presence is not taken into consideration properly in the analyses of neutrino data, the interference terms arising due to the additional CP phases in presence of a sterile neutrino can severely impact the physics searches in long baseline (LBL) neutrino oscillation experiments. In the current work we consider one light (eV-scale) sterile neutrino and probe all the three CP phases (${\delta }_{13}$, ${\delta }_{24}$, ${\delta }_{34}$) in the context of the upcoming Deep Underground Neutrino Experiment (DUNE) and also estimate how the results improve when data from NOvA, T2K and T2HK are added in the analysis. We illustrate the $\Delta {\chi }^2$ correlations of the CP phases among each other, and also with the three active-sterile mixing angles. Finally, we briefly illustrate how the relevant parameter spaces in the context of neutrinoless double beta decay get modified in light of the bounds in presence of a light sterile neutrino.

    hep-phhep-exJHEP(2021)·9 citations
20. 20*

    Directional recoil detection

    Sven E. Vahsen🇺🇸 · Ciaran A. J. O'Hare🇦🇺 · Dinesh Loomba🇺🇸

    Searches for dark matter-induced recoils have made impressive advances in the last few years. Yet the field is confronted by several outstanding problems. First, the inevitable background of solar neutrinos will soon inhibit the conclusive identification of many dark matter models. Second, and more fundamentally, current experiments have no practical way of confirming a detected signal's galactic origin. The concept of directional detection addresses both of these issues while offering opportunities to study novel dark matter and neutrino-related physics. The concept remains experimentally challenging, but gas time projection chambers are an increasingly attractive option, and when properly configured, would allow directional measurements of both nuclear and electron recoils. In this review, we reassess the required detector performance and survey relevant technologies. Fortuitously, the highly-segmented detectors required to achieve good directionality also enable several fundamental and applied physics measurements. We comment on near-term challenges and how the field could be advanced.

    ↳ physics.ins-detastro-ph.COhep-phAnn.Rev.Nucl.Part.Sci.(2021)·91 citations
21. 21*

    Diversity + Inclusion at Belle II: Where We Are, What We've Done and Where We Want To Be

    S.A. De La Motte🇦🇺 · H.M. Wakeling🇨🇦 · M.Barrett🇯🇵 · K.Kinoshita🇺🇸

    The Belle II Collaboration comprises over 1000 international high energy physicists, who investigate the properties of $b$-quarks and other particles at the luminosity frontier. In order to achieve our aim of a successful physics program, it is essential that we emphasise contributions from a diverse community. Belle II has thus far focused on diversity in gender and sexuality, among other efforts within our collaboration. These efforts are led by our two Diversity Officers, elected to the newly created positions in 2018. Their role has been to promote an inclusive atmosphere, raising awareness of diversity and being a safe first point of call for issues of discrimination and harassment. These proceedings accompany the short talk delivered during ICHEP 2020, marking the first conference the Belle II Collaboration has presented in the diversity and inclusion stream. It details the efforts described above, as well as examining the evolving gender demographics of our community, since membership began in 2011.

    ↳ physics.ed-phhep-exhep-phphysics.soc-phPoS(2021)·0 citations
22. 22*

    On connection between perturbation theory and semiclassical expansion in quantum mechanics

    A.V. Turbiner🇺🇸 · E. Shuryak🇺🇸

    It is shown that for the one-dimensional anharmonic oscillator with potential $V(x)=a{x}^2+bg{x}^3+\dots =\frac{1}{g^2}\hat{V}(gx)$, as well as for the radial oscillator $V(r)=\frac{1}{g^2}\hat{V}(gr)$ and for the perturbed Coulomb problem $V(r)=\frac{\alpha }{r}+\beta gr+\dots =g\tilde{V}(gr)$, the Perturbation Theory in powers of the coupling constant $g$ (weak coupling regime) and the semiclassical expansion in powers of ${\hslash }^{1/2}$ for the energies coincide. This is related to the fact that the dynamics developed in two spaces: $x(r)$-space and $gx(gr)$-space, lead to the same energy spectra. The equations which govern dynamics in these two spaces, the Riccati-Bloch equation and the Generalized Bloch equation, respectively, are presented. It is shown that the perturbation theory for the logarithmic derivative of the wavefunction in $gx(gr)$- space leads to (true) semiclassical expansion in powers of ${\hslash }^{1/2}$; for the one-dimensional case this corresponds to the flucton calculus for the density matrix in the path integral formalism in Euclidean (imaginary) time proposed by one of the authors, Shuryak(1988). Matching the perturbation theory in powers of $g$ and the semiclassical expansion in powers of ${\hslash }^{1/2}$ for the wavefunction leads to a highly accurate local approximation in the entire coordinate space, its expectation value for the Hamiltonian provides a prescription for the summation of the perturbative (trans)-series.

    ↳ quant-phhep-lathep-phhep-thNPB(2023)·2 citations
23. 23*

    Cosmological dynamics and bifurcation analysis of the general non-minimally coupled scalar field models

    Wompherdeiki Khyllep🇮🇳 · Jibitesh Dutta🇮🇳

    Non-minimally coupled scalar field models are well-known for providing interesting cosmological features. These include a late time dark energy behavior, a phantom dark energy evolution without singularity, an early time inflationary universe, scaling solutions, convergence to the standard $\Lambda$CDM, etc. While the usual stability analysis helps us determine the evolution of a model geometrically, bifurcation theory allows us to precisely locate the parameters' values describing the global dynamics without a fine-tuning of initial conditions. Using the center manifold theory and bifurcation analysis, we show that the general model undergoes a transcritical bifurcation, which predicts us to tune our models to have certain desired dynamics. We obtained a class of models and a range of parameters capable of describing a cosmic evolution from an early radiation era towards a late time dark energy era over a wide range of initial conditions. There is also a possible scenario of crossing the phantom divide line. We also find a class of models where the late time attractor mechanism is indistinguishable from that of a structurally stable general relativity based model; thus, we can elude the big rip singularity generically. Therefore, bifurcation theory allows us to select models that are viable with cosmological observations.

    ↳ gr-qchep-phhep-thEPJC(2021)·8 citations
24. 24*

    Isospin-1/2 $D\pi$ scattering and the lightest $D_0^{\ast }$ resonance from lattice QCD

    Luke Gayer🇮🇪 · Nicolas Lang🇮🇪 · Sinéad M. Ryan🇮🇪 · David Tims🇮🇪 · Christopher E. Thomas🇬🇧 · David J. Wilson🇬🇧

    Isospin-1/2 $D\pi$ scattering amplitudes are computed using lattice QCD, working in a single volume of approximately $(3.6\mathrm{fm}{)}^3$ and with a light quark mass corresponding to $m_{\pi }\approx 239$ MeV. The spectrum of the elastic $D\pi$ energy region is computed yielding 20 energy levels. Using the Lüscher finite-volume quantisation condition, these energies are translated into constraints on the infinite-volume scattering amplitudes and hence enable us to map out the energy dependence of elastic $D\pi$ scattering. By analytically continuing a range of scattering amplitudes, a $D_0^{\ast }$ resonance pole is consistently found strongly coupled to the $S$-wave $D\pi$ channel, with a mass $m\approx 2200$ MeV and a width $\Gamma \approx 400$ MeV. Combined with earlier work investigating the $D_{s0}^{\ast }$, and $D_0^{\ast }$ with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the $D_0^{\ast }$ is consistently found well below that of the $D_{s0}^{\ast }$, in contrast to the currently reported experimental result.

    ↳ hep-lathep-phJHEP(2021)·74 citations
25. 25*

    Cosmology from confinement?

    Mark Van Raamsdonk🇨🇦

    We describe a class of holographic models that may describe the physics of certain four-dimensional big-bang / big-crunch cosmologies. The construction involves a pair of 3D Euclidean holographic CFTs each on a homogeneous and isotropic space $M$ coupled at either end of an interval $\mathcal{I}$ to a Euclidean 4D CFT on $M\times \mathcal{I}$ with many fewer local degrees of freedom. We argue that in some cases, when the size of $M$ is much greater than the length of $\mathcal{I}$, the theory flows to a gapped / confining three-dimensional field theory on $M$ in the infrared, and this is reflected in the dual description by the asymptotically AdS spacetimes dual to the two 3D CFTs joining up in the IR to give a Euclidean wormhole. The Euclidean construction can be reinterpreted as generating a state of Lorentzian 4D CFT on $M\times \mathrm{time}$ whose dual includes the physics of a big-bang / big-crunch cosmology. When $M$ is ${\mathbb{R}}^3$, we can alternatively analytically continue one of the ${\mathbb{R}}^3$ directions to get an eternally traversable four-dimensional planar wormhole. We suggest explicit microscopic examples where the 4D CFT is $\mathcal{N}=4$ SYM theory and the 3D CFTs are superconformal field theories with opposite orientation. In this case, the two geometries dual to the pair of 3D SCFTs can be understood as a geometrical version of a brane-antibrane pair, and the tendency of the geometries to connect up is related to the standard instability of brane-antibrane systems.

    ↳ hep-thgr-qchep-phJHEP(2022)·67 citations

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