Mon·Jan 29, 2024Monday·January 29, 2024

1. 01*

   Gluon distributions and mass decompositions of the pion and kaon

   Chengdong Han🇨🇳 · Wei Kou🇨🇳 · Rong Wang🇨🇳 · Xurong Chen🇨🇳

   We present the gluon distribution functions of pion and kaon in small-$x$ and large-$x$ regions, and compare them with the results obtained from lattice QCD and continuum Schwinger function methods. Whether in the small-$x$ region or the large-$x$ region, our gluon distribution of pion is consistent with the results of lattice QCD and continuum Schwinger function method. In addition, the first four moments of gluon distributions of pion and kaon at different $Q^2$ scales are calculated. Furthermore, we present the mass decompositions of pion and kaon with the dynamical parton distribution functions calculated by the DGLAP equation with parton-parton recombination corrections. The mass structures of pion and kaon are totally different from that of the proton.

   hep-phEPJC(2024)·3 citations
2. 02*

   Role of Coulomb interaction in elastic pion-proton scattering from holography

   Yu-Peng Zhang🇨🇳 · Xun Chen🇨🇳 · Xiao-Hua Li🇨🇳 · Akira Watanabe🇨🇳

   Differential cross sections of the elastic pion-proton scattering are investigated at very small momentum transfer in a holographic QCD model, considering both the strong and Coulomb interaction in the Regge regime. The strong interaction is described by the Pomeron and Reggeon exchange, and the Coulomb interaction is characterized by the one photon exchange. The two interactions are linked through an interference term and we only need to determine a single adjustable parameter involved in this term. As to the parameters for the strong interaction, we can utilize the values determined in the previous studies. The differential cross sections can be predicted without any additional parameters, and it is shown that our predictions are consistent with the experimental data. We explicitly show the momentum transfer dependence for the interference effect. The energy dependence of the contribution ratios for each component is also discussed.

   hep-phhep-exnucl-exnucl-thPRD(2024)·4 citations
3. 03*

   Heavy Neutral Leptons in Gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ at Muon Collider

   Ru-Yi He🇨🇳 · Jia-Qi Huang🇨🇳 · Jin-Yuan Xu🇨🇳 · Fa-Xin Yang🇨🇳 · Zhi-Long Han🇨🇳 · Feng-Lan Shao🇨🇳

   Heavy neutral leptons $N$ are the most appealing candidates to generate the tiny neutrino masses. In this paper, we study the signature of heavy neutral leptons in gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ at a muon collider. Charged under the $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry, the heavy neutral leptons can be pair produced via the new gauge boson $Z^{\prime }$ at muon collider as ${\mu }^{+}{\mu }^{-}\to Z^{\prime \ast }\to NN$ and ${\mu }^{+}{\mu }^{-}\to Z^{\prime (\ast )}\gamma \to NN\gamma$. We then perform a detailed analysis on the lepton number violation signature ${\mu }^{+}{\mu }^{-}\to NN\to {\mu }^{\pm }{\mu }^{\pm }{W}^{\mp }{W}^{\mp }$ and ${\mu }^{+}{\mu }^{-}\to NN\gamma \to {\mu }^{\pm }{\mu }^{\pm }{W}^{\mp }{W}^{\mp }\gamma$ at the 3 TeV muon collider, where the hadronic decays of $W$ boson are treated as fat-jets $J$. These lepton number violation signatures have quite clean backgrounds at the muon collider. Our simulation shows that a wide range of viable parameter space is within the reach of the 3 TeV muon collider. For instance, with new gauge coupling $g^{\prime }=0.6$ and an integrated luminosity of 1000 fb${}^{-1}$, the ${\mu }^{\pm }{\mu }^{\pm }JJ$ signal could probe $m_{Z^{\prime }}\lesssim 12.5$ TeV. Meanwhile, if the gauge boson mass satisfies $2m_N<m_{Z^{\prime }}<\sqrt{s}$, the ${\mu }^{\pm }{\mu }^{\pm }JJ\gamma$ signature would be more promising than the ${\mu }^{\pm }{\mu }^{\pm }JJ$ signature.

   hep-phhep-exCPC(2024)·15 citations
4. 04*

   Positron supercritical resonances and spontaneous positron creation in slow collisions of heavy nuclei

   D.A. Telnov🇷🇺 · N.K. Dulaev🇷🇺 · Y.S. Kozhedub🇷🇺 · I.A. Maltsev🇷🇺 · R.V. Popov🇷🇺 · I.I. Tupitsyn🇷🇺 · V.M. Shabaev🇷🇺

   We present a theoretical and computational study of positron supercritical resonances in systems consisting of two highly-charged bare nuclei. The resonance positions and widths depending on the internuclear separation are calculated with the help of the complex-scaling generalized pseudospectral method in modified prolate spheroidal coordinates. The results are applied to estimate the probability of spontaneous positron creation in slow U${}^{92+}$--U${}^{92+}$ and Cm${}^{96+}$--Cm${}^{96+}$ collisions.

   hep-phnucl-thPhys.Atom.Nucl.(2024)·2 citations
5. 05*

   Asymmetric collisions in MadGraph5_aMC@NLO

   Laboni Manna🇵🇱 · Anton Safronov🇵🇱 · Carlo Flore🇮🇹 · Daniel Kikola🇵🇱 · Jean-Philippe Lansberg🇫🇷 · Olivier Mattelaer🇧🇪

   We will gain unprecedented, high-accuracy insights into the internal structure of the atomic nucleus thanks to lepton-hadron collision studies in the coming years at the Electron-Ion-Collider (EIC) in the United States. A good control of radiative corrections is necessary for the EIC to be fully exploited and to extract valuable information from various measurements. We present our extension of photoproduction at fixed order in MadGraph5_aMC@NLO, a widely used framework for (next-to-)leading order calculations at the Large Hadron Collider (LHC). It applies to electron-hadron collisions, in which the quasi-real photon comes from an electron as well as to proton-nucleus and nucleus-nucleus collisions.

   hep-phhep-exnucl-thPoS(2024)·1 citation
6. 06*

   Violation of the equivalence principle induced by oscillating rest mass and transition frequency, and its detection in atom interferometers

   Jordan Gué🇫🇷 · Aurélien Hees🇫🇷 · Peter Wolf🇫🇷

   We present a theoretical investigation of the expected experimental signals produced by freely falling atoms with time oscillating mass and transition frequency. These oscillations could be produced in a variety of models, in particular, models of scalar dark matter (DM) non universally coupled to the standard matter (SM) such as axion-like particles (ALP) and dilatons. Performing complete and rigorous calculations, we show that, on one hand, two different atomic species would accelerate at a different rate, and on the other hand, they would produce a non-zero differential phase shift in atom interferometers (AI). The former would produce observable signals in equivalence principle tests like the recent MICROSCOPE mission, and we provide a corresponding sensitivity estimate, showing that MICROSCOPE can reach beyond the best existing searches in the ALP case. We also compare the expected sensitivity of two future AI experiments, namely the AION-10 gradiometer and an isotope differential AI considered for MAGIS-100, that we will refer to as SPID. We show that the SPID setup would be more sensitive to these dark matter fields compared to the gradiometer one, assuming equivalent experimental parameters.

   hep-phastro-ph.COgr-qcphysics.atom-phPRD(2024)·14 citations
7. 07*

   Ab initio calculation of molecular pentaquark magnetic moments in heavy pentaquark chiral perturbation theory

   Hao-Song Li🇨🇳

   We propose a new heavy pentaquark chiral perturbation theory for the recently observed hidden-charm pentaquark states by LHCb Collaboration. With the ab initio constructed chiral Lagrangians, we present a parameter-free calculation of the octet molecular pentaquark magnetic moments up to one-loop level. We improve the quark model description of the data when we include the leading SU(3) breaking effects coming from the one-loop corrections. Without any experimental inputs, our predictions are so simple and unique that we regard them as a theoretical benchmark to be compared with experiments as well as other theoretical models.

   hep-phPRD(2024)·33 citations
8. 08*

   Magnetic moments and axial charges of the octet hidden-charm molecular pentaquark family

   Hao-Song Li🇨🇳 · Fei Guo🇨🇳 · Ya-Ding Lei🇨🇳 · Feng Gao🇨🇳

   In this work, we calculate the magnetic moment and axial charge of the octet hidden-charm molecular pentaquark family in quark model. The Coleman-Glashow sum-rule for the magnetic moments of pentaquark family is always fulfilled independently of SU(3) symmetry breaking. In the $8_{2f}$ flavor representation, the magnetic moments of hidden-charm molecular pentaquark states with spin configuration $J^P={\frac{1}{2}}^{-}({\frac{1}{2}}^{+}\otimes 0^{-})$ are all equal to ${\mu }_c=0.38{\mu }_N$. The axial charges of octet hidden-charm molecular pentaquark states are quite small compared to the axial charge of nucleon. The axial charges of the pentaquark states with the spin configuration $J^P={\frac{1}{2}}^{-}({\frac{1}{2}}^{+}\otimes 0^{-})$ in $8_{2f}$ flavor representation are all zero.

   hep-phPRD(2024)·37 citations
9. 09*

   Study of spin polarization dependence on rapidity, transverse momentum, and azimuthal angle

   Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Rajeev Singh🇺🇸

   We investigate the spacetime evolution of spin polarization within a hydrodynamic framework based on the de Groot--van Leeuwen--van Weert expressions for energy-momentum and spin tensors. The system's deviation from boost invariance results in the interplay of different spin polarization components, impacting spin observables. We specifically examine the transverse momentum, azimuthal angle, and rapidity dependence of the mean spin polarization vector of $\Lambda$ hyperons. Our results qualitatively align with other models and experimental data on global spin polarization rapidity dependence. While the quadrupole structure is absent in the longitudinal component at midrapidity, our analysis reveals non-trivial signal at forward rapidities that differs from predictions based on the Bjorken expansion.

   hep-phnucl-thPoS(2024)·0 citations
10. 10*

    Benchmark calculations of fully heavy compact and molecular tetraquark states

    Wei-Lin Wu🇨🇳 · Yan-Ke Chen🇨🇳 · Lu Meng🇩🇪 · Shi-Lin Zhu🇨🇳

    We calculate the mass spectrum of the S-wave fully heavy tetraquark systems $QQ\bar{Q}\bar{Q}(Q=c,b)$ with both normal $(J^{PC}=0^{++},1^{+-},2^{++})$ and exotic $(J^{PC}=0^{+-},1^{++},2^{+-})$ C-parities using three different quark potential models (AL1, AP1, BGS). The exotic C-parity systems refer to the ones that cannot be composed of two S-wave ground heavy quarkonia. We incorporate the molecular dimeson and compact diquark-antidiquark spatial correlations simultaneously, thereby discerning the actual configurations of the states. We employ the Gaussian expansion method to solve the four-body Schrödinger equation, and the complex scaling method to identify the resonant states. The mass spectra in three different models qualitatively agree with each other. We obtain several resonant states with $J^{PC}=0^{++},1^{+-},2^{++},1^{++}$ in the mass region $(6.92,7.30)\mathrm{GeV}$, some of which are good candidates of the experimentally observed $X(6900)$ and $X(7200)$. We also obtain several exotic C-parity zero-width states with $J^{PC}=0^{+-}$ and $2^{+-}$. These zero-width states have no corresponding S-wave diquarkonium threshold and can only decay strongly to final states with P-wave quarkonia. With the notation $T_{4Q,J(C)}(M)$, we deduce from the root mean square radii that the $X(7200)$ candidates $T_{4c,0(+)}(7173),T_{4c,2(+)}(7214)$ and the state $T_{4c,1(-)}(7191)$ look like molecular states although most of the resonant and zero-width states are compact states.

    hep-phhep-exhep-latnucl-thPRD(2024)·46 citations
11. 11*

    An analysis of the gluon distribution with next-to-leading order splitting function in small-$x$

    Jingxuan Chen🇨🇳 · Xiaopeng Wang🇨🇳 · Yanbing Cai🇨🇳 · Xurong Chen🇨🇳 · Qian Wang

    An approximated solution for gluon distribution from DGLAP evolution equations with NLO splitting function in the small-$x$ limit is presented. We first obtain the simplified forms of LO and NLO splitting functions in the small-$x$ limit. With these approximated splitting functions, we obtain the analytical gluon distribution by using the Mellin transform. The free parameters in the boundary conditions are obtained by fitting the CJ15 gluon distribution data. We find that the asymptotic behavior of gluon distribution are consistent with the CJ15 data, however, the NLO results with the consideration of ``ladder'' structure of gluon emission are slightly better than those from LO. These results indicate that the corrections from NLO is significant and is necessary for a better description of the behavior of the gluon distribution in small-$x$ region. In addition, we investigate the DGLAP evolution of the proton structure function by using the analytical solution of the gluon distribution. The differential structure function shows that our results have a similar tendency with CJ15 at small-$x$.

    hep-phCPC(2024)·3 citations
12. 12*

    Direct WIMP detection rates for transitions in isomeric nuclei

    M.V Smirnov🇩🇪 · G. Yang🇺🇸 · Yu.N. Novikov🇷🇺 · J.D. Vergados🇬🇷 · D. Bonatsos🇬🇷

    The direct detection of dark matter constituents, in particular the weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper we study WIMP induced transitions from isomeric nuclear states for two possible isomeric candidates: ${}^{180}\mathrm{Ta}$ and ${}^{166}\mathrm{Ho}$. The experimental setup, which can measure the possible decay of ${}^{180}\mathrm{Ta}$ induced by WIMPs, was proposed. The corresponding estimates of the half-life of ${}^{180}\mathrm{Ta}$ are given in the sense that the WIMP-nucleon interaction can be interpreted as ordinary radioactive decay.

    hep-phnucl-exnucl-thNPB(2024)·4 citations
13. 13*

    A New Determination of the (Z,A) Dependence of Coherent Muon-to-Electron Conversion

    Léo Borrel🇺🇸 · David G. Hitlin🇺🇸 · Sophie Middleton🇺🇸

    Should muon-to-electron conversion in the field of a nucleus be found in the current generation of experiments, the measurement of the atomic number dependence of the process will become an important experimental goal. We present a new treatment of the (Z,A) dependence of coherent muon-to-electron conversion in 236 isotopes. Our approach differs from previous treatments in several ways. Firstly, we include the effect of permanent quadrupole deformation on the charged lepton flavor violating matrix elements, using the method of Barrett moments. This method also enables the addition of muonic X-ray nuclear size and shape determinations of the charge distribution to the electron scattering results used previously. Secondly, we employ a Hartree-Bogoliubov model to calculate neutron-related matrix elements for even-even nuclei. This takes into account the quadrupole deformation of the neutron distributions and the fact that neutrons are, in general, in different shell model orbits than protons. The calculated conversion rates differ from previous calculations, particularly in the region of large permanent quadrupole deformation. Finally, we propose an alternative normalization of the muon-to-electron conversion rated, which related more closely to what a given experiment acturally measures, and better separate lepton physics from nuclear physics effects.

    hep-phhep-exnucl-thNPA(2025)·13 citations
14. 14*

    Non-Unitary $3\times 3$ Mixing in Majorana Neutrinos and Vector-like Quark Models

    Pedro M. F. Pereira🇵🇹

    Non-unitary $3\times 3$ mixing matrices are present in many extensions of the Standard Model. One of the most simple extensions is the addition of $n_R$ right-handed neutrinos without imposing Lepton Number Conservation ($n_R$$\nu$SM). In the region of the parameter space where the usual seesaw approximation is valid, deviations from $3\times 3$ unitarity of the leptonic mixing matrix are negligible, while one has three light neutrinos and two or three heavy neutrinos with masses close to the GUT scale. This gap between the mass scales occurs while having order 1 Yukawa couplings, providing a natural explanation for the smallness of light neutrino masses - hence the name seesaw. Other regions of the parameter space, with lighter heavy neutrinos - with an eV or keV mass, for instance - and bigger deviations from unitarity of the leptonic mixing matrix, are still allowed by experiment. In fact, whenever heavy neutrino masses are many orders of magnitude below the GUT scale there are interesting phenomenological implications at low energies. To analyse such regions with precision, one needs an exact parameterisation, since approximations that were valid in the usual seesaw case now fail. This thesis will consist of a study and classification of regions of the 3$\nu$SM parameter space in the light of a newly-developed exact parameterisation. Furthermore, it will also include a study of models with vector-like quarks, another simple extension of the SM, that contains a $3\times 3$ non-unitary quark mixing matrix. Studying the most interesting regions of the parameter space of vector-like quarks models also benefits from the use of the aforementioned exact parameterisation. These regions are phenomenologically rich and may explain certain open questions like the CKM unitarity problem/Cabibbo angle anomaly. A chapter discussing the experimental implications of these models is also included.

    hep-ph0 citations
15. 15*

    Rebuttal of 'Note on "Vacuum stability of a general scalar potential of a few fields"'

    Kristjan Kannike🇪🇪

    We show that the recent 'Note on "Vacuum stability of a general scalar potential of a few fields"' [arXiv:2401.13863] erroneously misses the possibility that the Higgs portal term may have a different sign for different values of the two singlet fields. Due to this mistake, the derived vacuum stability conditions are sufficient, but not necessary.

    hep-ph0 citations
16. 16*

    Long-lived doubly charged scalars in the left-right symmetric model: catalyzed nuclear fusion and collider implications

    Evgeny Akhmedov🇩🇪 · P. S. Bhupal Dev🇺🇸 · Sudip Jana🇩🇪 · Rabindra N. Mohapatra🇺🇸

    We show that the doubly charged scalar from the $SU(2{)}_R$-triplet Higgs field in the Left-Right Symmetric Model has its mass governed by a hidden symmetry so that its value can be much lower than the $SU(2{)}_R$ breaking scale. This makes it a long-lived particle while being consistent with all existing theoretical and experimental constraints. Such long-lived doubly charged scalars have the potential to trigger catalyzed fusion processes in light nuclei, which may have important applications for energy production. We show that it could also bear consequences on the excess of large ionization energy loss ($dE/dx$) recently observed in collider experiments.

    hep-phhep-exnucl-exnucl-thPLB(2024)·8 citations
17. 17*

    Predictive linear seesaw model with $\Delta \left(27\right)$ family symmetry

    A. E. Cárcamo Hernández🇨🇱 · Ivo de Medeiros Varzielas🇵🇹 · Juan Marchant González🇨🇱

    We consider a model that accounts for the smallness of neutrino masses through the linear seesaw mechanism and employs a $\Delta (27)$ family symmetry to address the flavour problem. The model is predictive in the leptonic sector and faces constraints from Lepton Flavour Violation processes, namely $\mu \to e\gamma$, which indicate a range for the Right-Handed neutrino mass.

    hep-phPTEP(2025)·5 citations
18. 18*

    Double parton distributions with flavor interference from lattice QCD

    Daniel Reitinger🇩🇪 · Christian Zimmermann🇫🇷 · Markus Diehl🇩🇪 · Andreas Schäfer🇩🇪

    We study double parton distributions with flavor interference in the nucleon and compare them with previous results for the flavor diagonal case. We investigate both unpolarized and polarized partons. We compare our lattice results with those obtained from the simple description of the proton in terms of an SU(6) symmetric three-quark wave function and find that this description fails for both flavor and polarization dependence. We also derive and test a factorization ansatz for the unpolarized flavor interference distribution in terms of single-parton distributions and find that this ansatz fails to a large extent.

    ↳ hep-lathep-phJHEP(2024)·10 citations
19. 19*

    Physical Yukawa Couplings in Heterotic String Compactifications

    Giorgi Butbaia🇬🇧 · Damián Mayorga Peña🇵🇹 · Justin Tan🇬🇧 · Per Berglund🇬🇧 · Tristan Hübsch🇺🇸 · Vishnu Jejjala🇿🇦 · Challenger Mishra🇬🇧

    One of the challenges of heterotic compactification on a Calabi-Yau threefold is to determine the physical $(27{)}^3$ Yukawa couplings of the resulting four-dimensional $\mathcal{N}=1$ theory. In general, the calculation necessitates knowledge of the Ricci-flat metric. However, in the standard embedding, which references the tangent bundle, we can compute normalized Yukawa couplings from the Weil-Petersson metric on the moduli space of complex structure deformations of the Calabi-Yau manifold. In various examples (the Fermat quintic, the intersection of two cubics in ${\mathbb{P}}^5$, and the Tian-Yau manifold), we calculate the normalized Yukawa couplings for $(2,1)$-forms using the Weil-Petersson metric obtained from the Kodaira-Spencer map. In cases where $h^{1,1}=1$, this is compared to a complementary calculation based on performing period integrals. A third expression for the normalized Yukawa couplings is obtained from a machine learned approximate Ricci-flat metric making use of explicit harmonic representatives. The excellent agreement between the different approaches opens the door to precision string phenomenology.

    ↳ hep-thhep-phAdv.Theor.Math.Phys.(2024)·28 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.