We investigate the decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> mesons, i.e., <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>d</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup></math>, and their antiparticles, to two light vector mesons (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>V</mi><mn>1</mn></msub><msub><mi>V</mi><mn>2</mn></msub></math>). We use the SU(2) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin symmetry, which relates <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>0</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>1</mn></math> decay amplitudes through the interchange <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo stretchy="false">↔</mo><mi>s</mi></math> and is an approximate symmetry of the Standard Model (SM), to relate the helicity amplitudes of these decays. Treating all the helicity amplitudes for these decays, and, hence, the reduced matrix elements, as free parameters, we find an acceptable solution within the SM, although this is driven by the fact that the number of observables is smaller than what is needed for a meaningful fit. To reduce the number of free parameters, we then use some apparently reasonable and theoretically motivated approximations, like the dominance of factorizable contributions over the nonfactorizable ones and, hence, a distinct hierarchy between the helicity amplitudes. We find that once the assumption of hierarchy is imposed, there is no solution, both in the exact <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin limit as well as when substantial <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin breaking is allowed for. The tension is primarily driven by the longitudinal polarization fractions in almost all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>1</mn></math> decays, which are significantly smaller than the corresponding theoretical predictions based on the SM and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin symmetry. This is particularly true for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mover accent="true"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo stretchy="true">¯</mo></mover></math>, for which the individual disagreement with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin-based expectation is more than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>7</mn><mi>σ</mi></math>. Within the SM framework, the only effective resolution would be to entirely disregard the hierarchy between the longitudinal and transverse helicity amplitudes in the heavy-quark limit, as dictated by naive factorization, implying that there must be large nonfactorizable contributions to all these decay amplitudes. We also explore whether some new physics in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi></math> sector that does not respect the hierarchy among the helicity amplitudes can reduce the tension for all the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>1</mn></math> modes. While the answer is partially in the affirmative, we find that, for simplistic new physics scenarios, the tension still exists and the fit remains poor enough, if the hierarchy exists among the SM amplitudes. Some possible scenarios for a complete solution of the puzzle are also suggested.

India

Debajyoti Choudhury

Suman Kumbhakar

Anirban Kundu

Soumitra Nandi

Polarization fractions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>V</mi><mn>1</mn></msub><msub><mi>V</mi><mn>2</mn></msub></math>: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin constraints and new physics signatures

The exploration of exotic hadrons provides a crucial testing ground for quantum chromodynamics in its nonperturbative regime. In this work, we perform a systematic study of the two-body strong decay properties of single-charm molecular pentaquarks in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Y</mi><mi>c</mi></msub><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup></math> systems, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Y</mi><mi>c</mi></msub><mo>=</mo><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Σ</mi><mi>c</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></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></math>. Employing an effective Lagrangian approach combined with hadronic molecular wave functions derived from the one-boson-exchange model, we compute the decay widths and branching ratios for a series of predicted states with strangeness <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>S</mi><mo stretchy="false">|</mo><mo>=</mo><mn>1</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>S</mi><mo stretchy="false">|</mo><mo>=</mo><mn>2</mn></math>. Our calculations reveal distinctive decay patterns that serve as fingerprints for molecular identification. The total decay widths vary dramatically, from less than 1 MeV for the narrow <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Σ</mi><mi>c</mi></msub><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>I</mi><mo stretchy="false">(</mo><msup><mi>J</mi><mi>P</mi></msup><mo stretchy="false">)</mo><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn><mo stretchy="false">(</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup><mo stretchy="false">)</mo><mo stretchy="false">)</mo></math> state to several tens of MeV for broader coupled-channel molecules like <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup><mo>/</mo><msub><mi mathvariant="normal">Σ</mi><mi>c</mi></msub><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math>. A key finding is the stability of the predicted branching ratios against variations in the binding energy. The decay dynamics are dominated by light meson (particularly pion) exchange, leading to a strong preference for final states containing a charmed baryon and a strange meson. Furthermore, coupled-channel effects and isospin-related interference play essential roles in both the formation and decay mechanisms of specific candidates. The results provide concrete, testable predictions for future experimental searches at facilities such as LHCb and Belle II.

China

Xiao-Mei Tang

Jin-Yu Huo

Qi Huang

Rui Chen

Exploring two-body strong decay properties for possible single charm molecular pentaquarks with strangeness <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>S</mi><mo stretchy="false">|</mo><mo>=</mo><mn>1</mn></math>, 2

In a spin-1 hadron, tensor-polarized parton distribution functions (PDFs) exist. The twist-2 function is <italic>f</italic> <inf>1<italic>LL</italic></inf> and a twist-3 one is <italic>f<inf>LT</inf></italic>. Because an experiment is under preparation at the Thomas Jefferson National Accelerator Facility (JLab) to measure the cross section of electron-deuteron deep inelastic scattering with the tensor-polarized deuteron target, these PDFs need to be understood theoretically. Especially, measurements will be done in a relatively low- <italic>Q</italic> 2 region at JLab, so that twist-3 contributions could become sizable in the cross section. In a previous work, a twist-2 relation was derived for <italic>f<inf>LT</inf></italic> in terms of <italic>f</italic> <inf>1<italic>LL</italic></inf> by using a nonlocal operator, and it corresponds to the Wandzura-Wilczek (WW) relation between <italic>g</italic> <inf>1</inf> and <italic>g</italic> <inf>2</inf>. In addition, another relation similar to the Burkhardt-Cottingham (BC) sum rule was obtained. It is known that a formal way to derive the WW relation and the BC sum rule is to use the operator product expansion (OPE) with local operators. In this work, the WW-like relation and the BC-like sum rule for <italic>f<inf>LT</inf></italic> are derived by using the local OPE method as a reliable independent way to establish these relations.

Japan

S. Kumano

Kenshi Kuroki

Twist-2 relations for the twist-3 tensor-polarized distribution function <italic>f<inf>LT</inf></italic> of a spin-1 hadron by the operator-product-expansion method

Euclidean path integrals can be used to prepare states of a Lorentzian QFT. So long as any sources are turned off on the $\textit{t}$ = 0 surface, the resulting Lorentzian states all belong to the same Hilbert space. Constructing more states than allowed by the Lorentzian density of states means that the resulting states must be linearly dependent. For large amplitude sources and a fixed cutoff on energy, the AdS bulk dual of this effect has been conjectured to be captured by spacetime wormholes. Wormholes should then be generic in the presence of large such Euclidean sources; i.e., at large source amplitude one should find wormholes unless the source is fine-tuned in some way.

Canada

United States

Xiaoyi Liu

Donald Marolf

United Kingdom

Jorge Santos

Are $\textit{S}$ 1 × $\textit{S}$ 2 wormholes generic with large sources?

In the present work, we studied the $$T_{\bar{c}\bar{s}1}^f(2750)$$ state production through the meson loop mechanism in the $$B^+$$ meson decays, where $$T_{\bar{c}\bar{s}1}^f(2750)$$ is considered as a $$\bar{D}K^*$$ molecular state with $$J^P=1^+$$ . By employing the effective Lagrangian approach, we estimated the branching ratio of the $$B^+ \rightarrow D^+ T_{\bar{c}\bar{s}1}^{f}(2750)$$ and $$B^+ \rightarrow D^{*+} T_{\bar{c}\bar{s}1}^f(2750)$$ processes and found them to be on the order of $$10^{-5}\sim 10^{-4}$$ . The fit fraction of $$T_{\bar{c}\bar{s}1}^f(2750)$$ in different processes was also estimated. We propose to search for $$T_{\bar{c}\bar{s}1}^f(2750)$$ in the $$B^+ \rightarrow D^{*+}\bar{D}^{*-}K^+$$ process, which should be accessible to the Belle II and LHCb Collaborations.

Zhuo Yu

Qi Wu

Zi-Li Yue

Dian-Yong Chen

$$T_{\bar{c}\bar{s}1}^f(2750)$$ production in the $$B^+$$ decays processes

We study a $\textit{U}$ (1) extension of the Standard Model (SM) in which Dirac neutrino masses are generated radiatively at the one-loop level through the exchange of new beyond the SM fields. This framework establishes a direct connection between neutrino mass generation and the dark sector, with the stability of the dark matter ensured by a residual discrete $$ {\mathcal{Z}}_6 $$ symmetry arising from the spontaneous breaking of $\textit{U}$ (1) . We investigate the resulting charged lepton flavor violating processes and dark matter phenomenology, saturating relic observations and direct-detection constraints, and analyze the collider signatures of the dark sector at the Large Hadron Collider, its proposed high luminosity extension and at a future muon collider. We have identified excellent prospects for observing the considered dark matter candidates in these colliders, even with lower integrated luminosities than the proposed one.

Supriya Senapati

Chayan Majumdar

Utkarsh Patel

Sudhanwa Patra

Radiative Dirac neutrino masses and dark matter in a $\textit{U}$ (1) $\textit{B}$−$\textit{L}$ extended model

We investigate the vacuum-induced current density for a charged scalar field in a (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>D</mi><mo>+</mo><mn>1</mn></mrow></math>)-dimensional cosmic dispiration spacetime threaded by a magnetic flux. This background combines a cosmic string and a screw dislocation, yielding a nontrivial helical geometry. By constructing the normalized mode functions of the Klein-Gordon equation, we evaluate the Wightman function and obtain the vacuum expectation value of the current density. We show that, in addition to the azimuthal component describing a persistent current around the defect, a nonvanishing axial component is induced as a direct consequence of the helical structure of the spacetime. Both components are periodic functions of the magnetic flux depending only on its fractional part, reflecting the Aharonov-Bohm nature of the effect. Closed expressions are obtained for massive and massless fields in arbitrary dimensions. We demonstrate that the screw dislocation parameter plays a crucial role in the behavior of the induced currents, leading to the regularization of the components at the origin and controlling their magnitude. Their asymptotic behavior is also analyzed in detail. Our results reduce to known expressions in the absence of the screw dislocation, providing a consistency check. In particular, we examine the physically relevant (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>3</mn><mo>+</mo><mn>1</mn></mrow></math>)-dimensional case, where numerical analysis reveals nontrivial features arising from the interplay between topology and gauge effects.

Brazil

Herondy Mota

Vacuum-induced current density from a magnetic flux threading a cosmic dispiration in (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo>+</mo><mn>1</mn></math>)-dimensional spacetime

We study the (type 0B) $$ \mathcal{N} $$ = 1 supersymmetric complex Liouville string (S$\textit{ℂ}$LS), a supersymmetric extension of the bosonic complex Liouville string ($\textit{ℂ}$LS). We compute the sphere three-point amplitudes (including NS-NS-NS and NS-R-R types) and find they share the same form as the sphere three-point amplitude of the bosonic $\textit{ℂ}$LS. Analysis of the analytic structure of the NS-NS-NS-NS four-point amplitude and the higher equations of motion also yields results identical to the bosonic case. Based on these findings, we propose that the dual matrix model for the S$\textit{ℂ}$LS is the same as that for the bosonic $\textit{ℂ}$LS. We also investigate a related theory $$ \hat{\mathrm{S}\mathbb{C}\mathrm{LS}} $$ , which differs in the gauged worldsheet supersymmetry. A parallel analysis is performed for $$ \hat{\mathrm{S}\mathbb{C}\mathrm{LS}} $$ , and a candidate for its dual matrix model is proposed. We then carry out a partial numerical evaluation of the moduli space integral, which provides further evidence for both the proposals of the dual matrix model regarding S$\textit{ℂ}$LS and $$ \hat{\mathrm{S}\mathbb{C}\mathrm{LS}} $$ .

Zhengyuan Du

Kangning Liu

Zhe-fei Yu

$$ \mathcal{N} $$ = 1 super complex Liouville string

In this paper, pair production of standard model (SM)-like Higgs bosons, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mi>h</mi></math>, is studied through <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi></math> scattering at future electron-positron colliders, in the framework of the inert doublet model with two active doublets—i.e., the I(<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>1</mn><mo>+</mo><mn>2</mn></mrow></math>)HDM for short. The relevance of the process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi><mo stretchy="false">→</mo><mi>h</mi><mi>h</mi></math> for such a beyond-the-SM (BSM) scenario stems from the fact that it is a one-loop process at lowest order, wherein inert charged states <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>χ</mi><mo>±</mo></msup></math> contribute alongside <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>±</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>H</mi><mo>±</mo></msup></math>, and heavy fermions (primarily, bottom and top quarks), crucially, at the same perturbative order. Given that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>χ</mi><mo>±</mo></msup><mo>/</mo><msup><mi>H</mi><mo>±</mo></msup></math> masses and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><msup><mi>S</mi><mo>+</mo></msup><msup><mi>S</mi><mo>−</mo></msup></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>S</mi><mo>±</mo></msup><mo>=</mo><msup><mi>χ</mi><mo>±</mo></msup><mo>,</mo><msup><mi>H</mi><mo>±</mo></msup></math>) couplings are very mildly constrained, there exist regions of the parameter space of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">I</mi><mo stretchy="false">(</mo><mrow><mn>1</mn><mo>+</mo><mn>2</mn></mrow><mo stretchy="false">)</mo><mi>HDM</mi></math> where the former can be rather light and the latter rather large. After imposing up-to-date theoretical and experimental constraints on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">I</mi><mo stretchy="false">(</mo><mrow><mn>1</mn><mo>+</mo><mn>2</mn></mrow><mo stretchy="false">)</mo><mi>HDM</mi></math>, it is found that the production rates of such processes at future <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi></math> machines can be enhanced by up to a factor of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≈</mo><mn>50</mn></math> with respect to the SM, significantly exceeding typical yields of conventional two-Higgs-doublet models (2HDMs). Further, thanks to the level of control that one can attain at such facilities on the photon kinematics, leading to excellent invariant mass resolution of the incoming photon pairs, we show how it is possible to extract from this process the value of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>χ</mi><mo>±</mo></msup></math> mass (along with those of the active <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>H</mi><mo>±</mo></msup></math> states) with high precision, and whichever of the decays of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>h</mi><mi>h</mi></math> pair, both with and without beam polarization.

France

Morocco

Abdesslam Arhrib

Ayoub Hmissou

Sweden

Stefano Moretti

Larbi Rahili

Probing standard-model-like di-Higgs production at photon-photon colliders in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">I</mi><mo stretchy="false">(</mo><mrow><mn>1</mn><mo>+</mo><mn>2</mn></mrow><mo stretchy="false">)</mo><mi>HDM</mi></mrow></math> type-I

We conduct a mode analysis of a general <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><mo stretchy="false">)</mo></math>-charged first-order relativistic hydrodynamics within the framework of effective field theory for dissipative fluids in flat Minkowski spacetime. We derive the most general quadratic action for hydrodynamic modes, including stochastic noise, and analyze the corresponding dispersion relations in a consistent gradient expansion. We argue that spontaneous breaking of spacetime symmetry arises in the presence of a local thermal state specified by a local timelike four-vector. We demonstrate that hydrodynamical perturbations can be identified as Nambu-Goldstone modes, analogous to their embedding in global <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><mo stretchy="false">)</mo></math>-invariant theories. We find that frame-invariant combinations of hydrodynamic transport coefficients determine the first-order dispersion relations in the low-energy limit, making the mode analysis manifestly independent of the choice of hydrodynamic frame. Assuming local Kubo-Martin-Schwinger symmetry and unitarity of the underlying UV theory, we show that first-order hydrodynamics is stable if the enthalpy density is positive.

Atsuhisa Ota

Mode analysis of Nambu-Goldstone modes in U(1) charged first-order relativistic viscous hydrodynamics