We study the new $Z'$ boson as a portal for the production of Higgs bosons $h_0$ and $H_0$ predicted by the Bestest Little Higgs Model through Higgs-strahlung processes $\mu^+\mu^- \to (Z, Z') \to Zh_0, ZH_0$ . We focus on the resonant and nonresonant effects of the $Zh_0, ZH_0$ signals. In our analysis, we consider the center-of-mass energies of $\sqrt{s}=3, 4, 6, 10, 30$ TeV and integrated luminosities of ${\cal{L}}=2, 4, 6, 10, 30$ ${ {\rm{ab}}^{-1}}$ projected for a future muon collider. The possibility of performing precision measurements for Higgs bosons $h_0$ and $H_0$ is very promising for the future muon collider. Furthermore, our results may be useful to the High Energy Physics community. Complementarily, we generate and provide the Feynman rules necessary for studying processes $\mu^+\mu^- \to (Z, Z') \to Zh_0, ZH_0$ .

J.M. Martínez-Martínez

A. Gutiérrez-Rodríguez

E. Cruz-Albaro

M.A. Hernández-Ruíz

New $\textit{Z}$' boson of the bestest little Higgs model as a portal to signatures of Higgs bosons $\textit{h}$ $_{0}$ and $\textit{H}$ $_{0}$ at the future muon collider

We present a self-consistent dynamical holographic quantum chromodynamics (QCD) model to investigate the mass spectra and melting behavior of heavy and exotic mesons at finite temperature and finite density. Our approach is based on the Einstein-Maxwell-dilaton (EMD) framework and incorporates an elsewhere already introduced, albeit by hand, phenomenological nonquadratic dilaton profile. This allows one to capture the nonlinear Regge trajectories of heavy-flavor mesons and model certain exotic states. We show how to construct such models by actually solving the coupled Einstein, Maxwell, and dilaton field equations, ensuring mathematical self-consistency to replace any ad hoc input. At finite temperature, we analyze the confinement-deconfinement transition via a Hawking-Page phase transition. We compute the spectral functions, revealing the sequential melting of quarkonia as the temperature is increased. Extending to finite density, we explore the impact of baryon chemical potential on meson stability, showing significant modifications in spectral peaks and effective potentials that indicate a more rapid melting of mesonic states as the chemical potential increases in the deconfined phase. The dual of the small/large black hole transition now indicates toward a first order phase transition line ending at a second order critical point. Interestingly, the spectral functions smoothly cross this phase transition line.

Brazil

Belgium

Bruno Toniato

David Dudal

India

Subhash Mahapatra

Roldao da Rocha

Siddhi Swarupa Jena

Holographic QCD model for heavy and exotic mesons at finite density: A self-consistent dynamical approach

A series of vector charmonium(like) states, accompanied by a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi></math> meson, have been observed in the decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>B</mi></mrow></math> meson. These processes are color-suppressed at the quark level, as inferred from topological diagram analysis. In this work, we calculate the branching fractions of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>ψ</mi><mi>K</mi></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> denotes the charmonium(like) states <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>4040</mn><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3770</mn><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>4160</mn><mo stretchy="false">)</mo></math>. Our analysis incorporates both short-distance (naive factorization approach) and long-distance (final-state interactions) contributions. Within reasonable parameters, our results align with experimental data except for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>4160</mn><mo stretchy="false">)</mo></math>, suggesting its possible exotic nature. Furthermore, we find that long-distance contributions dominate these decay processes, highlighting the crucial role of final-state interactions in the productions of charmonium(like) states in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> decays.

China

Qi-Wei Yuan

Qi Wu

Ming-Zhu Liu

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math>-meson decays to vector charmoniumlike states and a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi></math> meson: The role of final-state interactions

We present a lattice quantum chromodynamics (QCD) determination of the vector and axial-vector form factors that describe the charm-baryon semileptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi mathvariant="normal">Ξ</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math>. The calculation uses a domain-wall action for the up, down, and strange quarks, and an anisotropic clover action for the charm quark. We use four ensembles of gauge-field configurations generated by the RBC and UKQCD collaborations, with lattice spacings between 0.111 and 0.073 fm and pion masses ranging from 420 to 230 MeV. We present Standard Model predictions for the decay rates and branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>−</mo></msubsup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>ℓ</mo><mo>=</mo><mi>e</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi></mrow></math>. In particular, we obtain <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Γ</mi><mo stretchy="false">(</mo><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><msup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub><mo stretchy="false">)</mo><mo>/</mo><mo stretchy="false">|</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>c</mi><mi>s</mi></mrow></msub><msup><mrow><mo stretchy="false">|</mo></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0.2515</mn><mo stretchy="false">(</mo><mn>73</mn><mo stretchy="false">)</mo><mtext> </mtext><mtext> </mtext><msup><mrow><mi>ps</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><msup><mi mathvariant="normal">Ξ</mi><mo>−</mo></msup><msup><mi>e</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>e</mi></msub><mo stretchy="false">)</mo><mo>=</mo><mn>3.58</mn><mo stretchy="false">(</mo><mn>12</mn><mo stretchy="false">)</mo><mo>%</mo></math>. These values are higher than those predicted by a previous lattice calculation and substantially higher than the experimentally measured values, but consistent with expectations from approximate <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><mo stretchy="false">)</mo></math> flavor symmetry.

United States

Callum Farrell

Stefan Meinel

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi mathvariant="normal">Ξ</mi></math> form factors from lattice QCD with domain-wall quarks: A new piece in the puzzle of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup></math> decay rates

We investigate the LHC discovery prospects for a second Higgs doublet through <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>H</mi></math> weak decay. The latter is identified as the smoking gun signature of two Higgs doublet models (2HDMs) with first-order electroweak (EW) phase transition, a necessary condition for EW baryogenesis. In the general 2HDM (G2HDM) that has flavor-changing neutral Higgs couplings, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>H</mi></math> may decay dominantly via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mo>+</mo><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></math> final states, giving rise to trilepton signals. By a phenomenological analysis, we show that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>H</mi></math> in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup><mi>t</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></math> final states could be a promising probe of G2HDM at the LHC with flavor violation.

Taiwan

Wei-Shu Hou

Mohamed Krab

Probing the general 2HDM with flavor violation through <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>H</mi></math>

J. Va’vra

Corrigendum to “A Simple Argument that Small Hydrogen May Exist” [ <italic>Physics Letters B</italic> Vol. 794, 2019, p. 130]

This article investigates the thermodynamic properties of the SU(2) Nambu–Jona–Lasinio (NJL) model under the chiral chemical potential $$ \mu _5 $$ , employing Tsallis non-extensive statistics. The introduction of the parameter $$ q $$ , which characterizes the non-extensivity of the system through Tsallis statistics, offers a novel perspective for studying the behavior of strongly interacting matter under extreme conditions. By calculating thermodynamic quantities such as quark mass, critical temperature, chiral density, pressure, entropy, and speed of sound, we systematically analyze the effects of $$ \mu _5 $$ and $$ q $$ on these quantities. It is observed that both $$ \mu _5 $$ and $$ q $$ exhibit an inverse relationship with the critical temperature $$ T_\textrm{pc} $$ , while showing a positive correlation with the chiral density $$\left\langle n_{5}\right\rangle $$ .

Xiang-Qiong Liu

The QCD phase diagram of the SU(2) NJL model with chiral chemical potential under a non-extensive framework

A large primordial lepton asymmetry can lead to successful baryogenesis by preventing the restoration of electroweak symmetry at high temperatures, thereby suppressing the sphaleron rate. This asymmetry can also lead to a first-order cosmic QCD transition, accompanied by detectable gravitational wave (GW) signals. By employing next-to-leading order dimensional reduction we determine that the necessary lepton asymmetry is approximately one order of magnitude smaller than previously estimated. Incorporating an updated QCD equation of state that harmonizes lattice and functional QCD outcomes, we pinpoint the range of lepton flavor asymmetries capable of inducing a first-order cosmic QCD transition. To maintain consistency with observational constraints from the Cosmic Microwave Background and Big Bang Nucleosynthesis, achieving the correct baryon asymmetry requires entropy dilution by approximately a factor of ten. However, the first-order QCD transition itself can occur independently of entropy dilution. We propose that the sphaleron freeze-in mechanism can be investigated through forthcoming GW experiments such as $\textit{μ}$Ares.

Fei Gao

Germany

Julia Harz

Spain

Chandan Hati

Yi Lu

Isabel Oldengott

United Kingdom

Graham White

Baryogenesis and first-order QCD transition with gravitational waves from a large lepton asymmetry

A loosely bound hadronic molecule produced by a relativistic heavy-ion collision has been described as a “snowball in hell” since it emerges from a hadron resonance gas whose temperature is orders of magnitude larger than the binding energy of the molecule. This remarkable phenomenon can be explained in terms of a novel thermodynamic variable called the “contact” that is conjugate to the binding momentum of the molecule. The production rate of the molecule can be expressed in terms of the contact density at the kinetic freeze-out of the hadron resonance gas. It approaches a nonzero limit as the binding energy goes to 0.

Eric Braaten

Kevin Ingles

Justin Pickett

Explaining Snowball-in-Hell Phenomena in Heavy-Ion Collisions Using a Novel Thermodynamic Variable

In this work, the electromagnetic structure of the hidden-charm pentaquark $$P_c(4337)$$ is investigated within the diquark–diquark–antiquark model using the QCD light-cone sum rule approach. The magnetic moments of the $$ P_c(4337) $$ state are calculated for the spin-parity assignments $$ J^P = \frac{1}{2}^- $$ and $$\frac{3}{2}^-.$$ The results are found to be $$ \mu _{P_c} = 1.76 \pm 0.44~\mu _N $$ for the $$ \frac{1}{2}^- $$ case and $$ \mu _{P_c} = -1.38 \pm 0.35~\mu _N $$ for the $$ \frac{3}{2}^- $$ scenario. These findings offer important insights into the internal quark-gluon structure and electromagnetic features of this multiquark system. Beyond their theoretical relevance, the results serve as essential benchmarks for future experimental studies aimed at determining the quantum numbers and underlying configuration of the $$ P_c(4337) .$$ Additionally, the electric quadrupole and magnetic octupole moments of the spin- $$\frac{3}{2}$$ state are extracted, indicating a non-spherical charge distribution for this exotic pentaquark.

Türkiye

Ulaş Özdem

Probing the electromagnetic structure of the $$P_c(4337)^+$$ pentaquark: insights from a diquark–diquark–antiquark picture for $$J^P = \frac{1}{2}^-$$ and $$\frac{3}{2}^-$$ states