We study the implications for $$B_s - \bar{B}_s$$ mixing and the neutron electric dipole moment (EDM) in a light dark matter model with sizable invisible rare meson decays to accommodate the recent possible deviations from Standard Model (SM) predictions observed in $$B^+\rightarrow K^+\nu \bar{\nu }$$ by Belle II and $$K^+\rightarrow \pi ^+\nu \bar{\nu }$$ by NA62. Given that the neutrinos in these decays escape detection, they can be replaced by other invisible final states. Based on effective operator analysis, it has been proposed that branching ratios for $$B^+\rightarrow K^+ +\text{ invisible }$$ and $$K^+\rightarrow \pi ^+ +\text{ invisible }$$ can naturally be larger than the SM predictions due to the emission of light dark matter pairs. We demonstrate that this scenario can be realized within a UV-complete two-Higgs-doublet model (2HDM) where neutral Higgs bosons mediating dark matter interactions induce significant low-energy effects especially for $$B_s-\bar{B}_s$$ mixing and neutron EDM. Within the allowed parameter space, we find non-negligible contributions to $$B_s - \bar{B}_s$$ mixing. For the neutron EDM, there is a cancellation due to the exchange of neutral spin-zero particles, but QCD renormalization group evolution will lift this cancellation which in fact is generally true for any neutral Higgs contribution. However, we demonstrate that such a cancellation does not occur for charged scalar contributions. Ultimately, the allowed CP-violating phases in the Yukawa sector can generate a neutron EDM at a level consistent with the current experimental bound.

China

Xuan Hong

Xiao-Gang He

Ming-Wei Li

A light DM model for large $$B \rightarrow K + \text{ invisible }$$ and $$K \rightarrow \pi + \text{ invisible }$$ decays and its implications for $$B_s-\bar{B}_s$$ mixing and neutron EDM

We perform three T-dualities on classical $$ \mathcal{N} $$ = 1 scale-separated AdS solutions of massive type IIA supergravity. These solutions arose from a compactification on a toroidal $\textit{G}$ -holonomy space with smeared O2 and O6/D6 sources. The T-dual backgrounds are classical $$ \mathcal{N} $$ = 1 AdS solutions of type IIB supergravity with O5/D5 and O9/D9 sources (type I) compactified on a space with $\textit{G}$ -structure and non-vanishing Ricci scalar. We generalize the original solutions in IIA in the T-dual picture and present on the type IIB side fully classical solutions with parametric control, scale separation, and integer conformal dimensions for the dual operators in the corresponding CFT. We also obtain strongly coupled solutions with the same properties. These are S-dual to parametrically controlled classical solutions of the heterotic SO(32) string theory.

United States

Zheng Miao

Spain

Muthusamy Rajaguru

George Tringas

Timm Wrase

T-dualities and scale-separated AdS3 in type I

We investigate the existence of the three-body molecular state composed of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> within the one-boson-exchange model. A major challenge is that while the pseudoscalar-meson couplings are well determined, the couplings for scalar- and vector-meson exchanges render significant model dependence. To ensure the reliability of our predictions and reduce model dependence, we recalibrate the coupling constants of the one-boson-exchange model. We treat the pole position of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math>, or equivalently the scalar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi></math>-exchange coupling constant, as the only unknown parameter. The coupling constants for the vector <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ω</mi></math> exchanges are determined by the pole positions of the well-established states <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub><mo stretchy="false">(</mo><mn>3875</mn><mo stretchy="false">)</mo></math>. We demonstrate that these parameter sets also successfully describe the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>s</mi><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>2870</mn><mo stretchy="false">)</mo></math> without further tuning. For the three-body system, our results indicate that an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>I</mi><mrow><mo stretchy="false">(</mo><msup><mi>J</mi><mi>P</mi></msup><mo stretchy="false">)</mo></mrow><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn><mrow><mo stretchy="false">(</mo><msup><mn>0</mn><mo>−</mo></msup><mo stretchy="false">)</mo></mrow></math> three-body molecular bound state exists when <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> is a virtual state located within approximately <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mn>10</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> threshold. Furthermore, we extend our analysis to the complex energy plane using the complex scaling method to search for molecular resonances, though no evidence of resonances is found in considered channels. We also apply this formalism to the bottom analog <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><msup><mi>B</mi><mo>*</mo></msup><msup><mi>K</mi><mo>*</mo></msup></math> system. In this sector, the conditions for the existence of a three-body bound state are more relaxed, as a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> virtual state located within <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mn>25</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> below the threshold suffices, although three-body molecular resonances remain absent. We suggest that future experiments precisely measure the pole position of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> or search for the three-body bound state in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mi>D</mi><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mi>π</mi><mi>π</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mi>D</mi><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover></math> channels, as these efforts would mutually illuminate the nature of the associated states.

Yan-Ke Chen

Lu Meng

Jun-Zhang Wang

Shi-Lin Zhu

Existence of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><msup><mi>B</mi><mo>*</mo></msup><msup><mi>K</mi><mo>*</mo></msup></math> three-body molecular states

In this paper, we investigate the dynamical constraints imposed on the UV theory when it develops an emergent symmetry in the infrared with mixed ’t Hooft anomalies. We demonstrate that, under certain conditions, the UV theory must contain non-genuine operators. Our primary examples illustrating this phenomenon are 2D gauged linear sigma models and 3D Chern-Simons-matter theories. Through this analysis, we establish connections between different classes of topological quantum field theories and propose a correspondence between quantum cohomologies of distinct target spaces.

Wei Gu

Denmark

Du Pei

Xingyang Yu

On mixed ’t Hooft anomalies of emergent symmetries

The non-leptonic $\textit{D}$ → $\textit{K}$ $\textit{K}$ and $\textit{D}$ → $\textit{π}$ $\textit{π}$ decays are powerful probes of the Standard Model and are related to each other through the $\textit{U}$ -spin symmetry of the strong interaction. Using lattice QCD inputs we calculate the corresponding colour-allowed tree amplitudes in factorisation and demonstrate that non-factorisable contributions and $\textit{U}$ -spin-breaking effects at the level of 50% allow us to accommodate the measured branching ratios in the Standard Model. An exciting direct probe of such non-factorisable and $\textit{U}$ -spin breaking effects is provided by the $$ {D}^0\to {K}_{\mathrm{S}}^0{K}_{\mathrm{S}}^0 $$ channel. This decay is governed by non-factorisable exchange topologies and essentially vanishes in the $\textit{U}$ -spin limit, although it is experimentally well established with a prominent branching ratio. Extrapolating our $\textit{D}$ → $\textit{K}$ $\textit{K}$ results using the isospin symmetry, we find a consistent benchmark picture. Specifically, we can accommodate the measured $$ {D}^0\to {K}_{\mathrm{S}}^0{K}_{\mathrm{S}}^0 $$ branching ratio with $\textit{U}$ -spin-breaking effects at the 50% level and exchange amplitudes at the level of 50% of the colour-allowed $\textit{D}$ → $\textit{K}$ $\textit{K}$ , $\textit{D}$ → $\textit{π}$ $\textit{π}$ tree contributions. Finally, we explore the resulting range for direct CP violation in $$ {D}^0\to {K}_{\mathrm{S}}^0{K}_{\mathrm{S}}^0 $$ , obtaining upper bounds in our benchmark scenarios of a few per mille, offering an exciting target for future measurements.

Netherlands

Robert Fleischer

Maria Piscopo

K. Vos

B. Zubaroğlu

Standard model benchmarks for $\textit{D}$ 0 → $\textit{K}$ − $\textit{K}$ +, $\textit{π}$ − $\textit{π}$ +, $$ {K}_{\mathrm{S}}^0{K}_{\mathrm{S}}^0 $$ decays

We present the yield, average transverse momentum, and collective flow calculations of <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> resonances in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Au</mi><mo>+</mo><mi>Au</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>19.6</mn></mrow></math>, 14.5, and 7.7 GeV using the AMPT model. It is found that, due to hadronic rescattering, the decay daughters of <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> interact with other particles in the medium, causing the yield of reconstructable <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> to be significantly suppressed, especially at low transverse momentum. The model results are compared with recent experimental data from Phase-II of the Beam Energy Scan (BES-II) program at the Relativistic Heavy-Ion Collider. The string-melting version of the AMPT model successfully reproduces the measured <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo>/</mo><mi>K</mi></mrow></math> ratios at all three analyzed collision energies. Interestingly, AMPT calculations that exclude the hadronic phase nevertheless provide a reasonable description of the data, thereby challenging the conventional interpretation that hadronic rescattering is the primary mechanism responsible for suppressing the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo>/</mo><mi>K</mi></mrow></math> ratio in central heavy-ion collisions. In addition, we find that the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo>/</mo><mi>K</mi></mrow></math> ratio appears to be largely insensitive to the lifetime of the hadronic phase, whereas the average transverse momentum, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>〈</mo><msub><mi>p</mi><mi>T</mi></msub><mo>〉</mo></mrow></math>, of the <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> shows a strong dependence, increasing significantly as the lifetime of the hadronic phase becomes longer. We further show that the directed flow <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>(</mo><msub><mi>v</mi><mn>1</mn></msub><mo>)</mo></math> of <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> mesons is strongly influenced by hadronic rescattering, whereas the elliptic flow <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>(</mo><msub><mi>v</mi><mn>2</mn></msub><mo>)</mo></math> exhibits only weak sensitivity to hadronic effects. These results establish <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> directed flow as a sensitive probe of the late-stage hadronic medium in heavy-ion collisions. These model calculations therefore provide valuable insight into the underlying physics governing the observed experimental results at RHIC.

India

Pranjal Barik

Kadambini Menduli

Aswini Kumar Sahoo

Md. Nasim

<math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></math> meson production using a multiphase transport model at RHIC BES energies

We present the first comprehensive study of the rare Dalitz decay $$K^*(892) \rightarrow K \ell ^+ \ell ^- (\ell = e, \mu )$$ , providing a prediction for the branching fraction and the dilepton mass spectrum. This decay involves the emission of a virtual photon which converts into a lepton pair, offering a probe of the transition form factor $$F_{K^*K}(q^2)$$ and underlying meson structure. Using a single pole approximation for the form factor, we present the calculation of the branching fraction for this rare decay channel for the first time. Furthermore, we also investigate the potential to search for a light $$A'$$ boson (dark photon) appearing as a narrow resonance in the dilepton spectrum, and discuss the experimental sensitivity and new physics opportunities at the dedicated BESIII experiment. Our results establish $$K^*(892) \rightarrow K \ell ^+ \ell ^- (\ell = e, \mu )$$ as a new laboratory for hadronic structure and dark-sector searches.

Benhou Xiang

Wanling Chang

Shuangshi Fang

Jingqing Zhang

Dalitz decay of $$K^*(892) \rightarrow K \ell ^+\ell ^-$$ : a new probe for hadronic structure and dark photon searches

The non-resonant production of a Higgs boson pair in association with a top-antitop quark pair $$ \left( pp\to t\overline{t} hh\right) $$ has only recently begun to be explored at the Large Hadron Collider (LHC) and provides a unique and largely uncharted probe of the top-Higgs sector, offering complementary sensitivity to the Higgs self-coupling and higher-dimensional interactions beyond the Standard Model. In this work, we present a detailed study of this process within the framework of Higgs Effective Field Theory (HEFT) at the High-Luminosity LHC (HL-LHC). A comparative analysis is performed using a traditional cut-based approach in the single-lepton channel and a multivariate parametric boosted decision tree method in both single-lepton and dilepton final states. We derive one- and two-parameter limits at 95% confidence level on the HEFT couplings $\textit{δκ}$ , $\textit{c}$ , $\textit{c}$ , $\textit{c}$ , and $\textit{c}$ . The projected bound on $\textit{δκ}$ is weaker than current experimental constraints from dedicated Higgs-pair measurement; however, this coupling plays a critical role in shaping the multidimensional allowed parameter space. For the remaining HEFT couplings, where no direct experimental limits currently exist, our results provide the first sensitivity projections in the $$ t\overline{t} hh $$ channel. Overall, this study demonstrates the strong potential of the $$ t\overline{t} hh $$ production process to probe extended Higgs and top-quark interactions beyond the Standard Model through the exploitation of the $$ t\overline{t} hh $$ data at the HL-LHC.

Brazil

Ricardo D’Elia Matheus

Oscar Éboli

Rafiqul Rahaman

France

Aurore Navarro

Exploring Higgs EFT in $$ t\overline{t} hh $$ at high luminosity LHC

We develop a novel model utilizing the forward <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mo>*</mo></msup></math> production reaction off the nucleon, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>π</mi><mi>N</mi><mo>→</mo><msup><mi>K</mi><mo>*</mo></msup><mi>M</mi><mi>B</mi></mrow></math>, induced by a high-momentum <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>π</mi></math> beam, as a tool to study low-lying <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>Y</mi><mo>*</mo></msup></math> resonances below and just above the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mover accent="true"><mi>K</mi><mo>¯</mo></mover><mi>N</mi></mrow></math> threshold. Because conventional <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>K</mi><mo>−</mo></msup><mi>p</mi></mrow></math> scattering experiments face difficulties in directly accessing this kinematic region, the proposed reaction offers a valuable complementary approach for <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>Y</mi><mo>*</mo></msup></math> spectroscopy. The constructed model is based on the one-meson exchange mechanism, which is known to dominate forward-angle production at high energies, and the half-off-shell scattering amplitudes from the ANL-Osaka dynamical coupled-channels models (Model A and Model B). We predict various observables, including differential cross sections and angular distributions. Our results demonstrate significant enhancements in the sub-threshold region of the invariant mass spectra. Notably, we show that overlapping resonances, such as a potential new <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow><mo> </mo><mi mathvariant="normal">Σ</mi></math> state and the well-established <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi mathvariant="normal">Σ</mi><mrow><mo>(</mo><mn>1385</mn><mo>)</mo></mrow><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></math>, can constitute a single peak in the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>π</mi><mi mathvariant="normal">Λ</mi></mrow></math> mass spectrum, indicating that the existence of previously unconfirmed subthreshold states cannot be ruled out by analyzing only the existing mass spectrum data. Furthermore, we find that angular distributions provide strong discriminatory power to disentangle such overlapping states through partial-wave interference effects, while the <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>t</mi><mo>′</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mi>ϕ</mi><mi>M</mi><mo>*</mo></msubsup></math> dependencies provide crucial constraints on the high-energy production mechanisms. Our predictions for these highly sensitive observables can facilitate high-statistics measurements, which are accessible at modern hadron facilities such as J-PARC, to unravel the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>S</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow><mo> </mo><msup><mi>Y</mi><mo>*</mo></msup></math> mass spectrum.

Japan

H. Kamano

T.S.H. Lee

Low-lying <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Λ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Σ</mi></math> resonances studied with the forward <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mo>*</mo></msup></math> productions off the proton induced by a high-momentum <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>π</mi></math> beam

In our earlier work [A. C. Wang et al., <a href="http://dx.doi.org/10.1103/PhysRevC.98.045209">Phys. Rev. C 98, 045209 (2018)</a>], we analyzed the differential cross-section data from the CLAS Collaboration for the reactions <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>γ</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup><msup><mi mathvariant="normal">Σ</mi><mn>0</mn></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>γ</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mi mathvariant="normal">Σ</mi><mo>+</mo></msup></mrow></math> using an effective Lagrangian approach. We found that a satisfactory description of the data required the inclusion of the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>s</mi></math>-channel <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi mathvariant="normal">Δ</mi><mrow><mo>(</mo><mn>1905</mn><mo>)</mo></mrow><mn>5</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></math> resonance, in addition to <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>t</mi></math>-channel exchanges of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>K</mi><mo>,</mo><mo> </mo><mi>κ</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>K</mi><mo>*</mo></msup><mo>,</mo><mo> </mo><mi>s</mi></math>-channel contributions from nucleon (<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Δ</mi><mo>,</mo><mo> </mo><mi>u</mi></math>-channel exchanges of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Λ</mi><mo>,</mo><mo> </mo><mi mathvariant="normal">Σ</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi mathvariant="normal">Σ</mi><mo>*</mo></msup></math>, and a generalized contact term. In the present work, we extend our analysis to incorporate the data on spin density matrix elements from the LEPS Collaboration for the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>γ</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mi mathvariant="normal">Σ</mi><mo>+</mo></msup></mrow></math> reaction at photon energies <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>E</mi><mi>γ</mi></msub><mo>=</mo><mn>1.85</mn><mo>–</mo><mn>2.96</mn><mspace width="0.28em"></mspace><mi>GeV</mi></mrow></math>. Our goal is to impose more stringent constraints on the theoretical model and obtain a more reliable understanding of the reaction mechanisms. We obtain two fits that describe the experimental data equally well. In both fits, the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi mathvariant="normal">Δ</mi><mrow><mo>(</mo><mn>1905</mn><mo>)</mo></mrow><mn>5</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></math> resonance plays an important role. However, the contribution from <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>t</mi></math>-channel <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>κ</mi></math> exchange is significant in one fit but negligible in the other. This finding contradicts earlier claims in the literature that the LEPS parity spin asymmetry <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>P</mi><mi>σ</mi></msub></math> data support a dominant role of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>κ</mi></math> exchange in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>γ</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mi mathvariant="normal">Σ</mi><mo>+</mo></msup></mrow></math>. We also present predictions for <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>P</mi><mi>σ</mi></msub></math> at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>E</mi><mi>γ</mi></msub><mo>=</mo><mn>8.5</mn></mrow></math> GeV, which may help clarify whether <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>κ</mi></math> exchange is indeed dominant in this reaction.

Ai-Chao Wang

Neng-Chang Wei

Fei Huang

Combined analysis of the data on cross sections and spin density matrix elements for <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>K</mi><mo>*</mo></msup><mi mathvariant="normal">Σ</mi></mrow></math> photoproduction reactions