Fri·Apr 10, 2020Friday·April 10, 2020

1. 01*

   ${\Lambda }_c^{\pm }$ production in pp collisions with a new fragmentation function

   B. A. Kniehl🇩🇪 · G. Kramer🇩🇪 · I. Schienbein🇫🇷 · H. Spiesberger🇩🇪

   We study inclusive ${\Lambda }_c^{\pm }$-baryon production in $pp$ collisions in the general-mass variable-flavor number scheme and compare with data from the LHCb, ALICE and CMS collaborations. We perform a new fit of the $c\to {\Lambda }_c^{+}$ fragmentation function combining $e^{+}{e}^{-}$ data from OPAL and Belle. The agreement with LHC data is slightly worse compared with a calculation using an older fragmentation function, and the tension between different determinations of ${\Lambda }_c^{\pm }$ production cross sections from the LHC experimental collaborations is not resolved. The ratio of data for ${\Lambda }_c^{+}$-baryon and $D^0$-meson production seems to violate the universality of $c$-charm quark to $c$-hadron fragmentation.

   hep-phPRD(2020)·50 citations
2. 02*

   On the universality of the KRK factorization scheme

   S. Jadach🇵🇱

   The factorisation scheme (FS) abbreviated as KRK FS including a new definition of the PDFs for initial hadrons was formulated while developing KrkNLO scheme of matching QCD NLO corrections for the hard process with the parton shower heavy boson production in hadron-hadron collision and for deep inelastic lepton-hadron scattering. KRK FS (originally called Monte Carlo FS) can be regarded as a variant of the $\overline{MS}$ system. It is therefore trivially universal, that is process independent. The question of its universality is formulated differently: As the basic role of KRK FS is to simplify drastically NLO corrections, the question is now whether the same {\em single} variant of PDFs in the KRK FS is able to achieve the same maximal simplification of the NLO corrections for {\em all processes} with one or two initial hadrons and any number of the final hadrons? Our answer is positive and the proof is elaborated in the present note within the Catani-Seymour subtraction methodology. KRK FS is mandatory in the KrkNLO method of matching NLO calculation and parton shower -- a much simpler alternative of POWHEG and/or MC\@ NLO. However, the use of KRK FS and the corresponding PDFs simplifies NLO calculations for any other method of calculating NLO corrections and for arbitrary processes as well.

   hep-phActa Phys.Polon.B(2020)·4 citations
3. 03*

   Higgs self-coupling measurements using deep learning in the $b\bar{b}b\bar{b}$ final state

   Jacob Amacker🇬🇧 · William Balunas🇬🇧 · Lydia Beresford🇬🇧 · Daniela Bortoletto🇬🇧 · James Frost🇬🇧 · Cigdem Issever🇬🇧 · Jesse Liu🇺🇸 · James McKee🇬🇧 · Alessandro Micheli🇬🇧 · Santiago Paredes Saenz🇬🇧 · Michael Spannowsky🇬🇧 · Beojan Stanislaus🇬🇧

   Measuring the Higgs trilinear self-coupling ${\lambda }_{hhh}$ is experimentally demanding but fundamental for understanding the shape of the Higgs potential. We present a comprehensive analysis strategy for the HL-LHC using di-Higgs events in the four $b$-quark channel ($hh\to 4b$), extending current methods in several directions. We perform deep learning to suppress the formidable multijet background with dedicated optimisation for BSM ${\lambda }_{hhh}$ scenarios. We compare the ${\lambda }_{hhh}$ constraining power of events using different multiplicities of large radius jets with a two-prong structure that reconstruct boosted $h\to bb$ decays. We show that current uncertainties in the SM top Yukawa coupling $y_t$ can modify ${\lambda }_{hhh}$ constraints by $\sim 20\%$. For SM $y_t$, we find prospects of $-0.8<{\lambda }_{hhh}/{\lambda }_{hhh}^{\text{SM}}<6.6$ at 68% CL under simplified assumptions for 3000~fb${}^{-1}$ of HL-LHC data. Our results provide a careful assessment of di-Higgs identification and machine learning techniques for all-hadronic measurements of the Higgs self-coupling and sharpens the requirements for future improvement.

   hep-phhep-exJHEP(2020)·32 citations
4. 04*

   Subleading Logarithmic QED Initial State Corrections to $e^{+}{e}^{-}\to {\gamma }^{\ast }/{Z^0}^{\ast }$ to $O({\alpha }^6{L}^5)$

   J. Ablinger🇦🇹 · J. Blümlein🇩🇪 · A. De Freitas🇩🇪 · K. Schönwald🇩🇪

   Using the method of massive operator matrix elements, we calculate the subleading QED initial state radiative corrections to the process $e^{+}{e}^{-}\to {\gamma }^{\ast }/Z^{\ast }$ for the first three logarithmic contributions from $O({\alpha }^3{L}^3),O({\alpha }^3{L}^2),O({\alpha }^{3}L)$ to $O({\alpha }^5{L}^5),O({\alpha }^5{L}^4),O({\alpha }^5{L}^3)$ and compare their effects to the leading contribution $O({\alpha }^6{L}^6)$ and one more subleading term $O({\alpha }^6{L}^5)$. The calculation is performed in the limit of large center of mass energies squared $s\gg m_e^2$. These terms supplement the known corrections to $O({\alpha }^2)$, which were completed recently. Given the high precision at future colliders operating at very large luminosity, these corrections are important for concise theoretical predictions. The present calculation needs the calculation of one more two--loop massive operator matrix element in QED. The radiators are obtained as solutions of the associated Callen--Symanzik equations in the massive case. The radiators can be expressed in terms of harmonic polylogarithms to weight {\sf w = 6} of argument $z$ and $(1-z)$ and in Mellin $N$ space by generalized harmonic sums. Numerical results are presented on the position of the $Z$ peak and corrections to the $Z$ width, ${\Gamma }_Z$. The corrections calculated result into a final theoretical accuracy for $\delta M_Z$ and $\delta {\Gamma }_Z$ which is estimated to be of O(30 keV) at an anticipated systematic accuracy at the FCC\_ee of \sim 100 keV. This precision cannot be reached, however, by including only the corrections up to $O({\alpha }^3)$.

   hep-phhep-thNPB(2020)·33 citations
5. 05*

   Cosmic-Ray Signatures of Dark Matter from a Flavor Dependent Gauge Symmetry Model with Neutrino Mass Mechanism

   Holger Motz🇯🇵 · Hiroshi Okada🇰🇷 · Yoichi Asaoka🇯🇵 · Kazunori Kohri🇯🇵

   We propose an extension to the Standard Model accommodating two families of Dirac neutral fermions and Majorana fermions under additional $U(1{)}_{e-\mu }\times Z_3\times Z_2$ symmetries where $U(1{)}_{e-\mu }$ is a flavor dependent gauge symmetry related to the first and second family of the lepton sector, which features a two-loop induced neutrino mass model. The two families are favored by minimally reproducing the current neutrino oscillation data and two mass difference squares and canceling the gauge anomalies at the same time. As a result, we have a prediction for neutrino masses. The lightest Dirac neutral fermion is a dark matter candidate with tree-level interaction restricted to electron, muon and neutrinos, which makes it difficult to detect in direct dark matter search as well as indirect search focusing on the $\tau$-channel, such as through $\gamma$-rays. It may however be probed by search for dark matter signatures in electron and positron cosmic rays, and allows interpretation of a structure appearing in the CALET electron+positron spectrum around 350-400 GeV as its signature, with a boost factor $\approx$40 Breit-Wigner enhancement of the annihilation cross section.

   hep-phastro-ph.COastro-ph.HEPRD(2020)·6 citations
6. 06*

   The order analysis for the two loop corrections to lepton MDM

   Shu-Min Zhao🇨🇳 · Xing-Xing Dong🇨🇳 · Lu-Hao Su🇨🇳 · Hai-Bin Zhang🇨🇳

   The experimental data of the magnetic dipole moment(MDM) of lepton($e$, $\mu$) is very exact. The deviation between the experimental data and the standard model prediction maybe come from new physics contribution. In the supersymmetric models, there are very many two loop diagrams contributing to the lepton MDM. In supersymmetric models, we suppose two mass scales $M_{SH}$ and $M$ with $M_{SH}\gg M$ for supersymmetric particles. Squarks belong to $M_{SH}$ and the other supersymmetric particles belong to $M$. We analyze the order of the contributions from the two loop diagrams. The two loop triangle diagrams corresponding to the two loop self-energy diagram satisfy Ward-identity, and their contributions possess particular factors. This work can help to distinguish the important two loop diagrams giving corrections to lepton MDM.

   hep-phEPJC(2020)·4 citations
7. 07*

   QCD Odderon: non linear evolution in the leading twist

   Carlos Contreras (UTFSM) Eugene Levin (Tel Aviv U./UTFSM) · Rodrigo Meneses (U. de Valparaiso) · Michael Sanhueza (UTFSM)

   In the paper we propose and solve analytically the non-linear evolution equation in the leading twist approximation for the Odderon contribution. We found three qualitative features of this solution, which differs the Odderon contribution from the Pomeron one :(i) the behaviour in the vicinity of the saturation scale cannot be derived from the linear evolution in a dramatic difference with the Pomeron case; (ii) a substantial decrease of the Odderon contribution with the energy; and (iii) the lack of geometric scaling behaviour. The two last features have been seen in numerical attempts to solve the Odderon equation.

   hep-phPRD(2020)·18 citations
8. 08*

   Photoproduction of axion-like particles in the NA64 experiment

   R. R. Dusaev🇷🇺 · D. V. Kirpichnikov🇷🇺 · M. M. Kirsanov🇷🇺

   Axion-like particles $a$ (ALPs) that couple to the Standard Model (SM) gauge fields could be observed in the high-energy photon scattering $\gamma N\to Na$ off nuclei followed by the $a\to \gamma \gamma$ decay. In the present paper we describe the calculation of the ALP production cross-section and the properties of this production. The cross section formulas are implemented in the program for the simulation of events in the NA64 experiment, the active electron beam dump facility at the CERN SPS. We study the prospects of the NA64 experiment to search for ALP in the $10\text{mbox}MeV\lesssim m_a\lesssim 100$ MeV mass range for the statistics corresponding to up to $5\times 10^{12}$ electrons on target (EOT).

   hep-phPRD(2020)·65 citations
9. 09*

   Natural Alignment in Multi-Higgs Doublet Models

   Neda Darvishi🇬🇧 · Apostolos Pilaftsis🇬🇧

   We present the complete set of continuous maximal symmetries that the potential of an $n$-Higgs Doublet Model ($n$HDM) should satisfy for natural Standard Model (SM) alignment. As a result, no large mass scales or fine-tuning is required for such alignment, which still persists even if these symmetries were broken softly by bilinear mass terms. In particular, the Maximal Symmetric $n$HDM (MS-$n$HDM) can provide both natural SM alignment and quartic coupling unification up to the Planck scale. Most remarkably, we show that the MS-2HDM is a very predictive extension of the SM governed by two only additional parameters: (i) the charged Higgs mass $M_{h^{\pm }}$ (or $m_{12}^2$) and (ii) $\tan \beta$, whilst the quartic coupling unification scale ${\mu }_X$ is predicted to assume two discrete values. With these two input parameters, the entire Higgs-mass spectrum of the model can be determined. Moreover, we obtain definite predictions of misalignment for the SM-like Higgs-boson couplings to the gauge bosons and to the quarks, which might be testable at future precision high-energy colliders.

   hep-phPoS(2020)·15 citations
10. 10*

    Dynamical Majorana Neutrino Masses and Axions

    Jean Alexandre🇬🇧 · Nick E. Mavromatos🇬🇧 · Alex Soto🇨🇱

    We discuss dynamical mass generation for fermions and pseudoscalar fields (axion-like particles (ALP)), in the context of effective theories containing Yukawa type interactions between the fermions and ALPs. We discuss both Hermitian and non-Hermitian Yukawa interactions, which are motivated in the context of some scenarios for radiative (anomalous) Majorana sterile neutrino masses in some effective field theories. The latter contain shift-symmetry breaking Yukawa interactions between sterile neutrinos and ALPs. We show that, for a Hermitian Yukawa interaction, there is no (pseudo)scalar dynamical mass generation, but there is fermion dynamical mass generation, provided one adds a bare (pseudo)scalar mass. The situation is opposite for an anti-Hermitian Yukawa model: there is (pseudo)scalar dynamical mass generation, but no fermion dynamical mass generation.In the presence of additional attractive four-fermion interactions, dynamical fermion mass generation can occur in these models, under appropriate conditions and range of their couplings.

    hep-phhep-thNPB(2020)·26 citations
11. 11*

    Magneto-Seebeck coefficient and Nernst coefficient of hot and dense hadron gas

    Arpan Das🇵🇱 · Hiranmaya Mishra🇮🇳 · Ranjita K. Mohapatra🇮🇳

    We discuss the thermoelectric effect of hot and dense hadron gas within the framework of the hadron resonance gas model. Using the relativistic Boltzmann equation within the relaxation time approximation we estimate the Seebeck coefficient of the hot and dense hadronic medium with a gradient in temperature and baryon chemical potential. The hadronic medium in this calculation is modeled by the hadron resonance gas (HRG) model with hadrons and their resonances up to a mass cutoff $\Lambda \sim 2.6$ GeV. We also extend the formalism of the thermoelectric effect for a nonvanishing magnetic field. The presence of magnetic field also leads to a Hall type thermoelectric coefficient (Nernst coefficient) for the hot and dense hadronic matter apart from a magneto-Seebeck coefficient. We find that generically in the presence of a magnetic field Seebeck coefficient decreases while the Nernst coefficient increases with the magnetic field. At higher temperature and/or baryon chemical potential these coefficients approach to their values at vanishing magnetic field.

    hep-phnucl-thPRD(2020)·31 citations
12. 12*

    Freeze-out and thermalization in relativistic heavy ion collisions

    Sourendu Gupta🇮🇳 · Debasish Mallick🇮🇳 · Dipak Kumar Mishra🇮🇳 · Bedangadas Mohanty🇮🇳 · Nu Xu🇨🇳

    High energy heavy-ion collisions in laboratory produce a form of matter that can test Quantum Chromodynamics (QCD), the theory of strong interactions, at high temperatures. One of the exciting possibilities is the existence of thermodynamically distinct states of QCD, particularly a phase of de-confined quarks and gluons. An important step in establishing this new state of QCD is to demonstrate that the system has attained thermal equilibrium. We present a test of thermal equilibrium by checking that the mean hadron yields produced in the small impact parameter collisions as well as grand canonical fluctuations of conserved quantities give consistent temperature and baryon chemical potential for the last scattering surface. This consistency for moments up to third order of the net-baryon number, charge, and strangeness is a key step in the proof that the QCD matter produced in heavy-ion collision attains thermal equilibrium. It is a clear indication for the first time, using fluctuation observables, that a femto-scale system attains thermalization. The study also indicates that the relaxation time scales for the system are comparable to or smaller than the life time of the fireball.

    hep-phnucl-exnucl-th15 citations
13. 13*

    Hierarchy of kinetic freeze-out parameters in low energy heavy-ion collisions

    Sudhir Pandurang Rode🇮🇳 · Partha Pratim Bhaduri🇮🇳 · Amaresh Jaiswal🇮🇳 · Ankhi Roy🇮🇳

    We study the mass dependent hierarchy of kinetic freeze-out parameters of hadrons in low energy heavy-ion collisions. For this purpose, the transverse momentum and rapidity spectra of the identified hadrons produced in central Pb+Pb collisions, available at SPS energies ranging from ${\mathrm{E}}_{\mathrm{Lab}}=20A-158A$ GeV, are analyzed within a generalized non boost-invariant blast wave model. We consider separate simultaneous fits for light hadrons (${\pi }^{-}$, $K^{\pm }$) and heavy strange hadrons ($\Lambda$, $\bar{\Lambda }$, $\varphi$, ${\Xi }^{\pm }$, ${\Omega }^{\pm }$), for which the transverse momentum spectra as well as rapidity spectra are available. We also perform a separate fit to transverse momentum spectra of charmonia ($J/\Psi$, ${\Psi }^{\prime }$) at $158A$ GeV collisions. We find a clear mass dependent hierarchy in the fitted kinetic freeze-out parameters. Further, we study the rapidity spectra using analytical Landau flow solution for non-conformal systems. We find that the fitted value of sound velocity in the medium also shows a similar hierarchy.

    hep-phnucl-thPRC(2020)·8 citations
14. 14*

    A note on oscillating neutrino states in quantum field theory

    Massimo Blasone🇮🇹 · Luca Smaldone🇨🇿

    In a recent paper (Eur. Phys. J. C 80: 68 (2020).), a definition of oscillating neutrino states in quantum field theory was proposed. We show that such definition can be derived in a particular case of the Blasone-Vitiello approach, when mass vacuum is chosen as the physical vacuum. We discuss some problems of such an approach, which appears to be mathematically inconsistent and physically not acceptable.

    hep-phMod.Phys.Lett.A(2020)·10 citations
15. 15*

    Dark matter and dark radiation from evaporating primordial black holes

    Isabella Masina🇮🇹

    Primordial black holes in the mass range from $10^{-5}$ to $10^9$ g might have existed in the early universe. Via their evaporation mechanism (completed before Big Bang Nucleosynthesis), they might have released stable particles beyond the Standard Model. We reconsider the possibility that such particles might constitute the main part or a fraction of the dark matter observed today, updating the impact on this scenario from warm dark matter constraints. If sufficiently light, stable particles from primordial black holes evaporation might also provide a significant contribution to dark radiation. We generalize previous studies on this interesting dark matter and dark radiation production mechanism, by including the effects of accretion and a possible amount of entropy non conservation. We also discuss in some detail specific examples of stable particle candidates beyond the Standard Model.

    hep-phastro-ph.COEur.Phys.J.Plus(2020)·176 citations
16. 16*

    On the effect of NSI in the present determination of the mass ordering

    Ivan Esteban🇪🇸 · M. C. Gonzalez-Garcia🇪🇸 · Michele Maltoni🇪🇸

    In a recent work by Capozzi et al (arXiv:1908.06992), it is observed that the introduction of non-standard neutrino-matter interactions considerably relaxes the preference of T2K and NO$\nu$A for normal over inverted mass ordering observed in the standard three-neutrino scenario. Motivated by this, in this note we update our previous global fit to investigate whether such result still holds once the information of solar, atmospheric and reactor experiments is taken into account. We find that the non-standard parameters responsible for the improvement of the inverted ordering fit to T2K and NO$\nu$A data are not compatible with the other oscillation experiments, and that the preference for NO is restored.

    hep-phhep-ex12 citations
17. 17*

    Discovering leptonic forces using non-conserved currents

    Jeff A. Dror🇺🇸

    Differences in lepton number (i.e., $L_e-L_{\mu }$, $L_e-L_{\tau }$, $L_{\mu }-L_{\tau }$, or combinations thereof) are not conserved charges in the Standard Model due to the observation of neutrino oscillations. We compute the divergence of the corresponding currents in the case of Majorana or Dirac-type neutrinos and show that, in the high energy limit, the vector interactions map onto those of a light scalar coupled to neutrinos with its coupling fixed by the observed neutrino masses and mixing. This leads to amplitudes with external light vectors that scale inversely with the vector mass. By studying these processes, we set new constraints on $L_i-L_j$ through a combination of semi-leptonic meson decays, invisible neutrino decays, neutrinoless double beta decays, and observations of Big Bang Nucleosynthesis/supernova, which can be much stronger than previous limits for vector masses below an eV. These bounds have important implications on the experimental prospects of detecting $L_i-L_j$ long-range forces.

    hep-phhep-exPRD(2020)·67 citations
18. 18*

    Higgs production in bottom quark fusion: Matching the 4- and 5-flavour schemes to third order in the strong coupling

    Claude Duhr🇨🇭 · Falko Dulat🇺🇸 · Valentin Hirschi🇨🇭 · Bernhard Mistlberger🇺🇸

    We present analytic results for the partonic cross sections for the production of a Higgs boson via the fusion of two bottom quarks at N${}^3$LO in QCD perturbation theory in the five-flavour scheme. We combine this perturbative result with NLO accurate predictions in the four-flavour scheme that include the full bottom quark mass dependence by appropriately removing any double-counting stemming from contributions included in both predictions. We thereby obtain state-of-the-art predictions for the inclusive production probability of a Higgs boson via bottom quark fusion at hadron colliders.

    hep-phJHEP(2020)·68 citations
19. 19*

    $Z$ plus jets production via double parton scattering in $pA$ collisions at the LHC

    B. Blok🇮🇱 · F. A. Ceccopieri (Technion)🇮🇱

    We present results on Zjj production via double parton scattering in pA collisions at the LHC. We perform the analysis at leading and next-leading order accuracy with different sets of cuts on jet transverse momenta and accounting for the single parton scattering background. By exploiting the experimental capability to measure the centrality dependence of the cross section, we discuss the feasibility of DPS observation in already collected data at the LHC and in future runs.

    hep-phhep-exnucl-exnucl-thEPJC(2020)·4 citations
20. 20*

    Studying the Landau mass parameter of the extended $\sigma$-$\omega$ model for neutron star matter

    David E. Alvarez-Castillo🇵🇱 · Alexander Ayriyan · Gergely Gábor Barnaföldi🇭🇺 · Péter Pósfay🇭🇺

    We present a Bayesian analysis of the Landau mass within the extended $\sigma$-$\omega$ model for neutron star matter. To this purpose, we consider the mass measurement of the object PSR 0740+6620, the tidal deformability estimation from the GW170817 and the mass-radius estimate of PSR J0030+0451 by NICER. Using Landau mass as free parameter of the theory, we rely on the prediction power of the Bayesian method to find the best value for this nuclear quantity.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thPhys.Part.Nucl.(2020)·12 citations
21. 21*

    Gravitational Wave from Axion-SU(2) Gauge Fields: Effective Field Theory for Kinetically Driven Inflation

    Yuki Watanabe🇩🇪 · Eiichiro Komatsu🇩🇪

    Building on Weinberg's approach to effective field theory for inflation, we construct an effective Lagrangian for a pseudo scalar (axion) inflaton field with shift symmetry. In this Lagrangian we allow the axion field to couple to non-Abelian gauge fields via a Chern-Simons term. We then analyze a class of inflation models driven by kinetic terms. We find that the observational constraints on the amplitudes of curvature perturbations and non-Gaussianity yield a lower bound for the tensor-to-scalar ratio of $r\gtrsim 5\times 10^{-3}$ from the vacuum fluctuation. The sourced gravitational wave from SU(2) gauge fields further increases the tensor-to-scalar ratio and makes the total gravitational wave partially chiral and non-Gaussian, which can be probed by polarization of the cosmic microwave background and direct detection experiments. We discuss constraints on parameter space due to backreaction of spin-2 particles produced by the gauge field.

    ↳ hep-thastro-ph.COgr-qchep-ph42 citations
22. 22*

    Trace preserving quantum dynamics using a novel reparametrization-neutral summation-by-parts difference operator

    Oskar Ålund🇸🇪 · Yukinao Akamatsu🇯🇵 · Fredrik Laurén🇸🇪 · Takahiro Miura🇯🇵 · Jan Nordström🇸🇪 · Alexander Rothkopf🇳🇴

    We develop a novel numerical scheme for the simulation of dissipative quantum dynamics following from two-body Lindblad master equations. All defining continuum properties of the Lindblad dynamics, hermiticity, positivity and in particular trace conservation of the evolved density matrix are preserved. The central ingredient is a new spatial difference operator, which not only fulfils the summation by parts (SBP) property but also implements a continuum reparametrization property. Using the time evolution of a heavy-quark anti-quark bound state in a hot thermal medium as an explicit example, we show how the reparametrization neutral summation-by-parts (RN-SBP) operator preserves the continuum properties of the theory.

    ↳ physics.comp-phhep-phnucl-thJ.Comput.Phys.(2021)·16 citations
23. 23*

    Feeddown contributions from unstable nuclei in relativistic heavy-ion collisions

    Volodymyr Vovchenko🇩🇪 · Benjamin Dönigus🇩🇪 · Behruz Kardan🇩🇪 · Manuel Lorenz🇩🇪 · Horst Stoecker🇩🇪

    We estimate the feeddown contributions from decays of unstable $A=4$ and $A=5$ nuclei to the final yields of protons, deuterons, tritons, ${}^3$He, and ${}^4$He produced in relativistic heavy-ion collisions at $\sqrt{s_{\mathrm{NN}}}>2.4$ GeV, using the statistical model. The feeddown contribution effects do not exceed 5% at LHC and top RHIC energies due to the large penalty factors involved, but are substantial at intermediate collision energies. We observe large feeddown contributions for tritons, ${}^3$He, and ${}^4$He at $\sqrt{s_{\mathrm{NN}}}\lesssim 10$ GeV, where they may account for as much as 70% of the final yield at the lower end of the collision energies considered. Sizable ($>10$%) effects for deuteron yields are observed at $\sqrt{s_{\mathrm{NN}}}\lesssim 4$ GeV. The results suggest that the excited nuclei feeddown cannot be neglected in the ongoing and future analysis of light nuclei production at intermediate collision energies, including HADES and CBM experiments at FAIR, NICA at JINR, RHIC beam energy scan and fixed-target programmes, and NA61/SHINE at CERN. We further show that the freeze-out curve in the $T$-${\mu }_B$ plane itself is affected significantly by the light nuclei at high baryochemical potential.

    ↳ nucl-thhep-phnucl-exPLB(2020)·36 citations
24. 24*

    Challenge for spontaneous CP violation in Type IIB orientifolds with fluxes

    Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵

    We systematically investigate possibilities of realizing the spontaneous CP violation in Type IIB flux compactifications on toroidal orientifolds. Our detailed analysis leads to the presence of flat directions at degenerate CP-breaking and -conserving vacua for a generic choice of three-form fluxes, indicating that flux compactifications are not sufficient to realize the spontaneous CP violation. Furthermore, the four-dimensional CP can be embedded into the duality symmetries, namely modular symmetries for a particular choice of fluxes.

    ↳ hep-thhep-phPRD(2020)·55 citations
25. 25*

    Nucleons and higher spin baryon resonances: an AdS/QCD configurational entropic incursion

    Luiz F. Ferreira🇧🇷 · Roldao da Rocha🇧🇷

    Families of $J^P=1/2+$ nucleons (N(939), N(1440), N(1710), N(1880), N(2100), N(2300)) and $J^P=3/2-$ nucleons (N(1520), N(1700), N(1875) and N(2120)) are scrutinized from the point of view of the configurational entropy (CE). The mass spectra of higher $J^P$ resonances in each one of these families are then obtained when configurational-entropic Regge trajectories, that relate the CE of nucleon families to both their $J^P$ spin and also to their experimental mass spectra, are interpolated. The mass spectra of the next generation of nucleon resonances are then compared to already established baryonic states in PDG. Besides the zero temperature case, the finite temperature analysis is also implemented.

    ↳ hep-thhep-phPRD(2020)·38 citations
26. 26*

    Proto-Strange Quark Star Structure

    Gholam Hossein Bordbar🇮🇷 · Fatemeh Sadeghi🇮🇷 · Fatemeh Kayanikhoo🇮🇷 · Ahmad Poostforush🇮🇷

    In this paper, we investigate the newborn strange quark stars with constant entropy. We also use the MIT bag model to calculate the thermodynamic properties in two cases; the density-dependent bag constant and the fixed bag constant (B = 90 MeV). We show that the equation of state becomes stiffer by using the density dependent bag constant and by increasing the entropy. Furthermore, we show that the adiabatic index of the system reaches to 4/3 at high densities. Later, we calculate the structure of a strange quark star using the equation of state and the general relativistic equations of hydrostatic equilibrium, the Tolman-Oppenheimer-Volkoff (TOV) equations. We show that the gravitational mass of the star decreases by increasing the entropy and the maximum gravitational mass is larger when we use the density-dependent bag constant at fixed central energy density. It is shown that the mass-radius relation for this system obeys M R^ 3 for different cases of the calculations. Finally, we show that for a given stellar mass considering the fixed bag constant, the maximum gravitational red shift of a strange quark star occurs at larger values of entropy.

    ↳ nucl-thgr-qchep-phIndian J.Phys.(2021)·11 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.