HEP Phenomenology·hep-ph
28 papers—24 primary·4 cross-listed·reconstructed*
In this lectures, we give a review about the Minimal Supersymmetric Standard Model (MSSM) with -Parity Violation because it provides an attractive way to generate neutrino masses, lepton mixing angles in acconcordance to present neutrino data.
H.R. Sharma (1)🇮🇳 · Srishti Nagu (2)🇮🇳 · Jyotsna Singh (2)🇮🇳 · R.B. Singh (2)🇮🇳 · Baba Potukuchi ((1) Department of Physics University of Jammu, Jammu, (2) Department of Physics Lucknow University, Lucknow)🇮🇳
The study of pion production and the effects of final state interactions (FSI) are important for data analysis in all neutrino experiments. For energies at which current neutrino experiments are being operated, a significant contribution to pion production is made by resonance production process. After its production, if a pion is absorbed in the nuclear matter, the event may become indistinguishable from quasi-elastic scattering process and acts as a background. The estimation of this background is very essential for oscillation experiments and requires good theoretical models for both pion production at primary vertex and after FSI. Due to FSI, the number of final state pions is significantly different from the number produced at primary vertex. As the neutrino detectors can observe only the final state particles, the correct information about the particles produced at the primary vertex is overshadowed by FSI. To overcome this difficulty, a good knowledge of FSI is required which may be provided by theoretical models incorporated in Monte Carlo (MC) neutrino event generators. In this work, we will present simulated events for two different MC generators - GENIE and NuWro, for pion production in CC interactions on Ar target in DUNE experimental set up. A brief outline of theoretical models used by generators is presented. The results of pion production are presented in the form of tables showing the occupancy of primary and final state pion topologies with 100 detector resolution and with kinetic energy detector threshold cuts. We observe that NuWro (v-19.02.2) is more transparent (less responsive) to absorption and charge exchange processes as compared to GENIE (v-3.00.06), pions are more likely to be absorbed than created during their intranuclear transport and there is need to improve detector technology to improve the detector threshold for better results.
Zhu-Fang Cui🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪
Conceptually, radii are amongst the simplest Poincaré-invariant properties that can be associated with hadrons and light nuclei. Accurate values of these quantities are necessary so that one may judge the character of putative solutions to the strong interaction problem within the Standard Model. However, limiting their ability to serve in this role, recent measurements and new analyses of older data have revealed uncertainties and imprecisions in the radii of the proton, pion, kaon, and deuteron. In the context of radius measurement using electron + hadron elastic scattering, the past decade has shown that reliable extraction requires complete elimination of bias associated with practitioner-dependent choices of data fitting functions. Different answers to that challenge have been offered; and this perspective describes the statistical Schlessinger point method (SPM), in unifying applications to proton, pion, kaon, and deuteron radii. Grounded in analytic function theory, independent of assumptions about underlying dynamics, free from practitioner-induced bias, and applicable in the same form to diverse systems and observables, the SPM returns an objective expression of the information contained in any data under consideration. Its robust nature and versatility make it suitable for use in many branches of experiment and theory.
Shuai Xu🇨🇳 · Sibo Zheng🇨🇳
We consider the scenario of composite Higgs with partial compositeness to address the muon g-2 anomaly. We show that this anomaly is resolved by one-loop correction due to composite muon partners with mass scale of order TeVs and large Yukawa coupling to composite Higgs, which is different from interpretations of vectorlike lepton models. We present parameter space by imposing indirect constraints from precise measurements on Higgs, Z and oblique electroweak parameters. We analyze direct constraints in light of both Drell-Yan and Higgs-associated productions of the composite muon partners at high-luminosity LHC. It turns out that the surviving parameter regions with the lighter composite muon mass below GeV can be excluded at 2 order by the Drell-Yan processes.
Yan Li🇨🇳 · Jia-Jun Wu🇨🇳
In hadron physics, molecular-like multihadron states can interact with compact multiquark states. The latter are modeled as bare states in the Hilbert space of a potential model. In this work, we study several potential models relevant to the bare state, and solve their inverse scattering problems. The first model, called "cc", is a separable potential model. We show that it can approximate (single-channel short-range) -wave near-threshold physics with an error of , where sets the maximum momentum of the near-threshold region and is the typical scale of the potential. The second model, called "bc", serves as the bare-state-dominance approximation, where interaction between continuum states is ignored. Under this model, even though the bare state is always crucial for a bound state's generation, a shallow bound state naturally tends to have a small bare-state proportion. Therefore, we need other quantities to quantify the importance of the bare state. The last model, called "bcc", is a combination of the first two models. This model not only serves as a correction to the bare-state-dominance approximation, but can also be used to understand the interplay between quark and hadron degrees of freedom. This model naturally leads to the presence of a Castillejo-Dalitz-Dyson (CDD) zero. We consider the energy decomposition of a bound state. The potential ratio of the bare-continuum interaction to the continuum self-interaction is proposed to understand how the bound state is generated. Model independently, an inequality for the potential ratio is derived. Based on the model "bcc", the CDD zero can be used to estimate the potential ratio. Finally, we apply these studies to the deuteron, meson, and , and analyze their properties.
Jose Bernabeu🇪🇸 · Francisco J. Botella🇪🇸 · Miguel Nebot (Valencia U. and IFIC)🇪🇸 · Alejandro Segarra (KIT, Karlsruhe, TTP)🇩🇪
-- Entanglement offers a conceptual alternative to the single charged B-decay asymmetry for the measurement of the direct CP violating phase. With and the 16 time-ordered double decay rate Intensities to depend on the relative phase between the the - and -decay amplitudes given by at tree-level. Several constraining consistencies appear. An intrinsic accuracy of the method at the level of could be achievable at Belle-II with an improved determination of the penguin amplitude to -channels from existing facilities.
Zoltan Nagy🇩🇪 · Davison E. Soper🇺🇸
One can use more than one scale variable to define the family of surfaces in the space of parton splitting parameters that define the evolution of a parton shower. In an earlier paper, we developed this idea for electron-positron annihilation. Here, we use multiple scale variables for a parton shower with initial state partons. Then we need a more sophisticated analysis because the evolution of parton distribution functions must be coordinated with the parton shower evolution. We make the needed connections more precise than in our earlier work, even for the case of just one scale variable. Then we develop an example with three scale variables, which leads to advantages compared to the usual shower formulation with only one scale variable. We provide results for Drell-Yan muon pair production.
A. Kunčinas🇵🇹 · O. M. Ogreid🇳🇴 · P. Osland🇳🇴 · M. N. Rebelo🇵🇹
In spite of the success of the Standard Model of Particle Physics, there are some theoretical predictions which are not yet fully established experimentally as well as some experimental observations which cannot be fitted within its theoretical framework, thus requiring physics beyond the Standard Model. One of these is a hypothetical non-luminous form of matter - dark matter. Models with an extended scalar electroweak sector yield plausible dark matter candidates. In this paper we study a specific model, C-III-a, from a family of -symmetric three-Higgs-doublet models. The model consists of two active SU(2) doublets and an inert one. The latter is inert due to a symmetry that survives the breaking of , and would accommodate a dark matter particle. We explore the model numerically, based on theoretical and experimental constraints. After applying a number of successive checks over the parameter space we found a viable dark matter mass region in the range . This region is drastically different from the Higgs-like dark matter states that have been proposed: the well-known Inert Doublet Model and models with three scalar doublets, with one or two inert doublets. Furthermore, the C-III-a model allows for spontaneous CP violation.
Yongtae Heo🇰🇷 · Dong-Won Jung🇰🇷 · Jae Sik Lee🇰🇷
We consider the implication of the recent CDF -mass anomaly in the general framework of two Higgs doublet model. We find that the large deviation of the and parameters from their SM values of zero leads to the upper limit of about TeV on the heavy charged and neutral Higgs bosons when it is combined with the theoretical constraints from the perturbative unitarity and for the Higgs potential to be bounded from below.
Roberto Grimaudo🇮🇹 · Claudio Guarcello🇮🇹 · Giovanni Filatrella🇮🇹 · Bernardo Spagnolo🇮🇹 · Davide Valenti🇮🇹
An effective quantum description of the axion is proposed as a two-level dynamic system together with a spin-spin Hamiltonian for a coupled axion-Josephson qubit system. The interaction between axion and Josephson Junction can be responsible for a resonance effect, when the axion and the Josephson frequencies match. Thus, experimentally detectable oscillations induced in the Josephson qubit by its interaction with the axion are clearly highlighted. This phenomenon, causing a periodic magnetization reversal in the junction, can be exploited for the axion detection in the quantum limit of low noise.
Xiao Kang Du🇨🇳 · Zhuang Li🇨🇳 · Fei Wang🇨🇳 · Ying Kai Zhang🇨🇳
Original Georgi-Machacek model can preserve the custodial symmetry at tree level after the electroweak symmetry breaking. Unless additional custodial symmetry breaking effects are significant, the new physics contributions to are always very small. Our numerical results show that ordinary GM model can contribute to a maximal amount GeV, which can not explain the new CDF-II anomaly on W boson mass. We propose firstly to introduce small misalignment among the triplet VEVs to increase , which can give large new physics contributions to . Such slightly misaligned triplet VEVs from custodial symmetry preserving scalar potential can still be allowed. Our numerical results indicate that the resulting can easily reach the range of CDF-II data and the splitting among the triplet VEVs () can be as small as GeV for GeV. We also propose to introduce an additional custodial symmetry breaking source by extending the GM model with a low scale RH neutrino sector, which can adopt the leptogenesis mechanism and allow moderately large coupling strength even for triplet VEVs of order GeV. With low scale RH neutrino mass scale of order TeV, the new physics contribution to can reach GeV and is much larger than that of ordinary GM model. Combining both custodial symmetry breaking effects, the small misalignment among the triplet VEVs and the moderately large couplings allowed with RH neutrino sector, the value of can still easily reach the range of CDF-II data, with a minimum splitting (among the triplet VEVs) approximately GeV for GeV.
Christian Brønnum-Hansen🇩🇪 · Kirill Melnikov🇩🇪 · Jérémie Quarroz🇩🇪 · Chiara Signorile-Signorile🇩🇪 · Chen-Yu Wang🇩🇪
We compute the non-factorisable corrections to -channel single-top quark production at the LHC. These peculiar corrections arise because of interactions between the heavy- and the light-quark lines and appear for the very first time at next-to-next-to-leading order in perturbative QCD. We find that the non-factorisable corrections change the single-top production cross section and the relevant kinematic distributions in this process by about half a percent.
Dibya S. Chattopadhyay🇮🇳 · Kaustav Chakraborty🇮🇳 · Amol Dighe🇮🇳 · Srubabati Goswami🇮🇳
We present compact analytic expressions for 3-flavor neutrino oscillation probabilities with invisible neutrino decay, where matter effects have been explicitly included. We take into account the possibility that the oscillation and decay components of the effective Hamiltonian do not commute. This is achieved by employing the techniques of inverse Baker-Campbell-Hausdorff (BCH) expansion and the Cayley-Hamilton theorem applied in the 3-flavor framework. If only the vacuum mass eigenstate decays, we show that the treatment of neutrino propagation may be reduced to an effective 2-flavor analysis in the One Mass Scale Dominance (OMSD) approximation. The oscillation probabilities for , , and -- relevant for reactor, long baseline and atmospheric neutrino experiments -- are obtained as perturbative expansions for the case of only decay, as well as for the more general scenario where all components of the decay matrix are non-zero. The analytic results thus obtained match the exact numerical results for constant density matter to a high precision and provide physical insights into possible effects of the decay of neutrinos as they propagate through Earth matter. We find that the effects of neutrino decay are most likely to be observable in . We also point out that at any long baseline, the oscillation dips in can show higher survival probabilities in the case with decay than without decay, and explain this feature using our analytic approximations.
Di Wang🇨🇳
Flavor symmetry is a powerful tool to analyze charmed baryon decays. In this work, we propose an approach to generate sum rules for the singly and doubly charmed baryon decays without writing the Wigner-Eckhart invariants explicitly. The sum rules are computed routinely in several master formulas. Hundreds of sum rules are found to serve as test of the flavor symmetry in the charmed baryon decays.
G. Martinelli🇮🇹 · M. Naviglio🇮🇹 · S. Simula🇮🇹 · L. Vittorio🇮🇹
In addition to the well-known decays, semileptonic processes offer the possibility to determine the Cabibbo-Kobayashi-Maskawa (CKM) matrix element . We implement the Dispersive Matrix (DM) approach to describe the hadronic Form Factors (FFs) for the transition in the whole kinematical range, starting from recent Lattice QCD computations at large values of the 4-momentum transfer. We extract from the experimental data, obtaining from and from decays. After averaging with the values of obtained from the channels [1,2] we get , which is compatible with the most recent inclusive estimate [3] at the level. In addition we test the Lepton Flavour Universality (LFU) by computing the ratios of the total decay rates (where is a light lepton), obtaining and . We also address the issue of the symmetry breaking by comparing the hadronic FFs entering the semileptonic and channels.
Neelima Agarwal · Sourav Pal🇮🇳 · Aditya Srivastav🇮🇳 · Anurag Tripathi🇮🇳
The correlators of Wilson-line operators in non-abelian gauge theories are known to exponentiate, and their logarithms can be organised in terms of the collections of Feynman diagrams called Cwebs. The colour factors that appear in the logarithm correspond to completely connected diagrams and are determined by the web mixing matrices. In this article we introduce several new concepts: (a) Normal ordering of the diagrams of a Cweb, (b) Fused-Webs (c) Basis and Family of Cwebs. We use these ideas together with a Uniqueness theorem that we prove to arrive at an understanding of the diagonal blocks, and several null matrices that appear in the mixing matrices. We demonstrate using our formalism that, once the basis Cwebs present upto order are determined, the number of exponentiated colour factors for several classes of Cwebs starting at order can be predicted. We further provide complete results for the mixing matrices, to all orders in perturbation theory, for two special classes of Cwebs using our framework.
Kingman Cheung🇹🇼 · Wai-Yee Keung🇺🇸 · Po-Yan Tseng🇹🇼
We investigate the iso-doublet vector leptoquark as a solution to the anomalies and , as well as explaining the muon and electron anomalous magnetic moments, and the very recent -mass anomaly.
Luca Di Luzio🇮🇹 · Marco Nardecchia🇮🇹 · Claudio Toni🇮🇹
We reconsider the case of light vectors coupled to anomalous fermionic currents, focussing on the interplay between UV and IR dynamics. Taking as a general framework the gauging of the Standard Model accidental symmetries, we show that it is possible to devise an anomaly-free UV completion with mostly-chiral heavy fermions such that anomalous Wess-Zumino terms are suppressed in the IR, thus relaxing would-be strong bounds from the longitudinal emission of light vectors coupled to non-conserved currents. We classify such scenarios and show that they will be extensively probed at the high-luminosity phase of the LHC via the measurement of the rate and the direct search for non-decoupling charged leptons.
Andreas Crivellin🇨🇭 · Matthew Kirk🇪🇸 · Teppei Kitahara🇯🇵 · Federico Mescia🇪🇸
The rare flavour changing top quark decay is a clear sign of new physics and experimentally very interesting due to the huge number of top quarks produced at the LHC. However, there are few (viable) models which can generate a sizable branching ratio for -- in fact vector-like quarks seem to be the only realistic option. In this paper, we investigate all three representations (under the Standard Model gauge group) of vector-like quarks (, and ) that can generate a sizable branching ratio for without violating bounds from physics. Importantly, these are exactly the three vector-like quarks which can lead to a sizable positive shift in the prediction for mass, via the couplings to the top quark also needed for a sizable Br(). Calculating and using the one-loop matching of vector-like quarks on the Standard Model Effective Field Theory, we find that Br() can be of the order of , and for , and , respectively and that in all three cases the large mass measurement can be accommodated.
Motoi Endo🇯🇵 · Satoshi Mishima🇯🇵
The CDF collaboration has recently reported an updated result on the -boson mass measurement, showing a deviation from the standard model prediction. The discrepancy may indicate new contributions to the Fermi coupling constant. We study simple extensions of the standard model by introducing an extra scalar, fermion or vector field. It is found that the tension implies the new physics existing in multi-TeV scales if the new coupling to the electron and/or muon is of order unity.
Thomas Biekötter🇩🇪 · Sven Heinemeyer🇪🇸 · Georg Weiglein🇩🇪
The CDF collaboration recently reported a measurement of the -bosos mass, , showing a large positive deviation from the Standard Model (SM) prediction. The question arises whether extensions of the SM exist that can accommodate such large values, and what further phenomenological consequences arise from this. A different type of deviation from the SM has been observed experimentally in the searches for light Higgs bosons. CMS has observed two local excesses in the and final states for a hypothetical Higgs-boson mass of GeV. These two excesses are compatible with the corresponding ATLAS limits. A third excess was observed in the Higgs-boson searches at LEP in the final state at the local confidence level at about the same Higgs-boson mass. It was shown recently that the three excesses can be described the the 2HDM extended with a real singlet (N2HDM) of Yukawa type IV, while being in agreement with all other theoretical and experimental constraints. We demonstrate that the parameter space that accomodates the three excesses can also give a large contribution to in agreement with the recent CDF measurement. We discuss further phenomenological consequences of this scenario.
Reuven Balkin🇮🇱 · Eric Madge🇮🇱 · Tony Menzo🇺🇸 · Gilad Perez🇮🇱 · Yotam Soreq🇮🇱 · Jure Zupan🇺🇸
We investigate the phenomenological implications of the recent mass measurement by the CDF collaboration, which exhibits tension with the standard model (SM) electroweak fit. Performing the fit to the electroweak observables within the SM effective field theory, we find that the new physics that contributes either to the determination of the electroweak vacuum expectation value, or to the oblique parameters, can improve the agreement with data. The best description is obtained from a fit where flavor universality is not required in the new physics operators, with 2 to 3 indications for several nonzero Wilson coefficients. We point out that top partners with order TeV masses could lead to the observed shift in the mass.
Martin Hoferichter🇨🇭 · Javier Menéndez🇪🇸 · Frederic Noël🇨🇭
Lepton-flavor-violating decays of light pseudoscalars, , are stringently suppressed in the Standard Model up to tiny contributions from neutrino oscillations, so that their observation would be a clear indication for physics beyond the Standard Model. However, in effective field theory such decays proceed via axial-vector, pseudoscalar, or gluonic operators, which are, at the same time, probed in spin-dependent conversion in nuclei. We derive master formulae that connect both processes in a model-independent way in terms of Wilson coefficients, and study the implications of current limits in titanium for the decays. We find that these indirect limits surpass direct ones by many orders of magnitude.
In this note I show that nonlocal generalization of the standard model (SM) with nonlocal scale TeV can explain recent CDF result on the W-mass measurement
Zhiqiang Miao🇨🇳 · Yaofeng Zhu🇨🇳 · Ang Li🇨🇳 · Feng Huang🇨🇳
The distribution of the dark matter (DM) in DM-admixed-neutron stars (DANSs) is supposed to be either a dense dark core or an extended dark halo, which is subject to the DM fraction of DANS () and the DM properties, such as the mass () and the strength of the self-interaction (). In this paper, we perform an in-depth analysis of the formation criterion for dark core/dark halo and point out that the relative distribution of these two components is essentially determined by the ratio of the central enthalpy of the DM component to that of the baryonic matter component inside DANSs. For the critical case where the radii of DM and baryonic matter are the same, we further derive an analytical formula to describe the dependence of on and for given DANS mass. The relative distribution of the two components in DANSs can lead to different observational effects. We here focus on the modification of the pulsar pulse profile due to the extra light-bending effect in the case of a dark-halo existence and conduct the first investigation of the dark-halo effects on the pulse profile. We find that the peak flux deviation is strongly dependent on the ratio of the halo mass to the radius of the DM component. Lastly, we perform Bayesian parameter estimation on the DM particle properties based on the recent X-ray observations of PSR J0030+0451 and PSR J0740+6620 by the Neutron Star Interior Composition Explorer.
Takahiro Nishi🇯🇵 · Kenta Itahashi🇯🇵 · DeukSoon Ahn🇯🇵 · Georg P.A. Berg🇺🇸 · Masanori Dozono🇯🇵 · Daijiro Etoh🇯🇵 · Hiroyuki Fujioka🇯🇵 · Naoki Fukuda🇯🇵 · Nobuhisa Fukunishi🇯🇵 · Hans Geissel🇩🇪 · Emma Haettner🇩🇪 · Tadashi Hashimoto🇯🇵 and 36 other authors
Modern theories of physics tell that the vacuum is not an empty space. Hidden in the vacuum is a structure of anti-quarks and quarks . The and pair has the same quantum number as the vacuum and condensates in it since the strong interaction of the quantum chromodynamics (QCD) is too strong to leave it empty. The condensation breaks the chiral symmetry of the vacuum. The expectation value is an order parameter. For higher temperature or higher matter-density, decreases reflecting the restoration of the symmetry. In contrast to these clear-cut arguments, experimental evidence is so far limited. First of all, the is nothing but the vacuum itself. It is neither visible nor perceptible. In this article, we unravel this invisible existence by high precision measurement of pionic atoms, -meson-nucleus bound systems. Using the as a probe, we demonstrate that is reduced in the nucleus at 58% of the normal nuclear density by a factor of 77 2% compared with that in the vacuum. This reduction indicates that the chiral symmetry is partially restored due to the extremely high density of the nucleus. The present experimental result clearly exhibits the existence of the hidden structure, the chiral condensate, in the vacuum.
James Brister🇨🇳 · Shihao Kou🇨🇳 · Zhengyi Li🇨🇳 · Longjie Ran🇨🇳 · Zheng Sun🇨🇳
This work makes an exhaustive search for generic renormalizable R-symmetric Wess-Zumino models with up to 5 chiral fields, and checks the consistency of their vacuum solutions with predictions from the Nelson-Seiberg theorem and its generalizations. Each model is recorded as the R-charge assignment of fields, which uniquely determines the cubic polynomial superpotentials with generic coefficients. Redundancy from permutation symmetries and reducible models are properly eliminated in the searching algorithm. We found that among 859 models in total, 19 of them have supersymmetric vacua unpredicted by the Nelson-Seiberg theorem and its generalizations. These exceptional models have their specific R-charge assignments covered by constructions found in previous literature. The search result can be used to estimate the accuracy of the field counting method for finding supersymmetric models in the string landscape. More applications of the dataset are expected in future work.
Demao Kong🇺🇸 · Manoj Kaplinghat🇺🇸 · Hai-Bo Yu🇺🇸 · Filippo Fraternali🇳🇱 · Pavel E. Mancera Piña🇳🇱
We analyze circular velocity profiles of seven ultradiffuse galaxies (UDGs) that are isolated and gas-rich. Assuming that the dark matter halos of these UDGs have a Navarro-Frenk-White (NFW) density profile or a Read density profile (which allows for constant-density cores), the inferred halo concentrations are systematically lower than the cosmological median, even as low as dex (about away) in some cases. Alternatively, similar fits can be obtained with a density profile that scales roughly as for radii larger than a few kiloparsecs. Both solutions require the radius where the halo circular velocity peaks () to be much larger than the median expectation. Surprisingly, we find an overabundance of such large- halos in the IllustrisTNG dark-matter-only simulations compared to the Gaussian expectation. These halos form late and have higher spins compared to median halos of similar masses. The inner densities of the most extreme among these late-forming halos are higher than their NFW counterparts, leading to a density profile. However, the two well-resolved UDGs in our sample strongly prefer lower dark matter densities in the center than the simulated ones. Comparing to IllustrisTNG hydrodynamical simulations, we also find a tension in getting both low enough circular velocities and high enough halo mass to accommodate the measurements. Our results indicate that the gas-rich UDGs present a significant challenge for galaxy formation models.
* 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.