We present a model for the distribution of the number of forward neutrons emitted in soft (minimum bias) and hard inelastic proton-nucleus (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>A</mi></mrow></math>) scattering at the CERN Large Hadron Collider. It is based on the Gribov-Glauber model for the distribution over the number of inelastic collisions (wounded nucleons) combined with a parametrization of cross section (color) fluctuations in the projectile proton, which depend on the parton momentum fraction <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>x</mi><mi>p</mi></msub></math>, and the assumption of independent neutron emissions. We observe that, while the effect of soft color fluctuations is modest, a reduction of the interaction strength with increasing <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>x</mi><mi>p</mi></msub></math> provides the dominant effect. It allows us to qualitatively describe the trend of the ATLAS data on the zero degree calorimeter (ZDC) energy spectra of forward neutrons emitted in dijet production in inelastic <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>A</mi></mrow></math> scattering 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>8.16</mn></mrow></math> TeV.

Italy

M. Alvioli

Finland

V. Guzey

United States

M. Strikman

Probing fluctuating protons using forward neutrons in soft and hard inelastic proton-nucleus scattering

Motivated by the recent LHCb measurements of the ratios between the branching ratios (BRs), <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>R</mi><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><mo>/</mo><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></msub><mo>≡</mo><mrow><mi>BR</mi></mrow><mo stretchy="false">(</mo><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo><mo>/</mo><mrow><mi>BR</mi></mrow><mo stretchy="false">(</mo><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>R</mi><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo>/</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub></mrow></msub><mo>≡</mo><mrow><mi>BR</mi></mrow><mo stretchy="false">(</mo><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo><mo>/</mo><mrow><mi>BR</mi></mrow><mo stretchy="false">(</mo><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo></math>, we analyze the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">(</mo><mi>P</mi><mo>,</mo><mi>V</mi><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> in the improved perturbative QCD (iPQCD) formalism, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub></math> denotes the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi></math>-wave charmonia with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math>, 1, 2, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi><mo stretchy="false">(</mo><mi>V</mi><mo stretchy="false">)</mo></math> denotes the pseudoscalars <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi></math> (the vectors <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"><msup><mi>K</mi><mo>*</mo></msup></math>). Our results <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>R</mi><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><mo>/</mo><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></msub><mo>=</mo><mn>0.32</mn><mo>±</mo><mn>0.05</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>R</mi><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo>/</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub></mrow></msub><mo>=</mo><mn>0.11</mn><mo>±</mo><mn>0.01</mn></math> at leading order in the strong coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mi>s</mi></msub></math> agree well with the data within uncertainties. The result <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>R</mi><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub><mo>/</mo><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></msub><mo>≡</mo><mrow><mi>BR</mi></mrow><mo stretchy="false">(</mo><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo><mo>/</mo><mrow><mi>BR</mi></mrow><mo stretchy="false">(</mo><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>π</mi><mo>+</mo></msup><mo stretchy="false">)</mo><mo>=</mo><mn>0.17</mn><mo>±</mo><mn>0.02</mn></math> is lower than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mn>1.41</mn><mrow><mo>−</mo><mn>0.45</mn></mrow><mrow><mo>+</mo><mn>0.50</mn></mrow></msubsup></math> inferred by the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub><msup><mi>π</mi><mo>+</mo></msup></math> measurement. The large longitudinal polarization fractions imply that these components dominate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn><mo>,</mo><mi>c</mi><mn>2</mn></mrow></msub><msup><mi>ρ</mi><mo>+</mo></msup></math> BRs. A peculiar constructive (destructive) interference between the twist-2 and twist-3 contributions is identified in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><msup><mi>ρ</mi><mo>+</mo></msup></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><msup><mi>π</mi><mo>+</mo></msup></math>) mode, but not in the corresponding ones with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn><mo>,</mo><mi>c</mi><mn>2</mn></mrow></msub></math> mesons. Inputting the BRs of the strong decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn><mo>,</mo><mi>c</mi><mn>2</mn></mrow></msub><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mo>/</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mo stretchy="false">(</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mo>/</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><mo stretchy="false">)</mo></math> reported by the BESIII Collaboration, we obtain those of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">(</mo><mi>ρ</mi><mo>,</mo><mi>π</mi><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> followed by secondary decay chains under the narrow-width approximation. All the above iPQCD predictions can be confronted by more precise experiments in the future to deepen our understanding of QCD dynamics in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub></math> transitions.

China

Xin Liu

Hsiang-nan Li

Zhen-Jun Xiao

Study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">(</mo><mi>P</mi><mo>,</mo><mi>V</mi><mo stretchy="false">)</mo></math> decays in the improved perturbative QCD formalism

All charmless <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math> denotes the light pseudoscalar meson and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>V</mi></math> denotes the vector meson) decays have not been experimentally observed to date, but some of them might be measured in the near future. The charmless <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays with the axial-vector (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi></math>) resonance states, the tensor (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>) resonance states, and the excited vector (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mrow><mi>E</mi><mo>,</mo><mi>D</mi></mrow></msub></math>) resonance states are studied based on flavor SU(3) analysis in this work, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mi>E</mi></msub></math> contains <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">{</mo><mi>ρ</mi><mo stretchy="false">(</mo><mn>1450</mn><mo stretchy="false">)</mo><mo>,</mo><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1410</mn><mo stretchy="false">)</mo><mo>,</mo><mi>ω</mi><mo stretchy="false">(</mo><mn>1420</mn><mo stretchy="false">)</mo><mo>,</mo><mi>ϕ</mi><mo stretchy="false">(</mo><mn>1680</mn><mo stretchy="false">)</mo><mo stretchy="false">}</mo></math> with quantum numbers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>n</mi><mrow><mn>2</mn><mi>S</mi><mo>+</mo><mn>1</mn></mrow></msup><msub><mi>L</mi><mi>J</mi></msub><mo>=</mo><msup><mn>2</mn><mn>3</mn></msup><msub><mi>S</mi><mn>1</mn></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mi>D</mi></msub></math> contains <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">{</mo><mi>ρ</mi><mo stretchy="false">(</mo><mn>1700</mn><mo stretchy="false">)</mo><mo>,</mo><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">(</mo><mn>1680</mn><mo stretchy="false">)</mo><mo>,</mo><mi>ω</mi><mo stretchy="false">(</mo><mn>1650</mn><mo stretchy="false">)</mo><mo>,</mo><mi>ϕ</mi><mo stretchy="false">(</mo><mn>2170</mn><mo stretchy="false">)</mo><mo stretchy="false">}</mo></math> with quantum numbers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>n</mi><mrow><mn>2</mn><mi>S</mi><mo>+</mo><mn>1</mn></mrow></msup><msub><mi>L</mi><mi>J</mi></msub><mo>=</mo><msup><mn>1</mn><mn>3</mn></msup><msub><mi>D</mi><mn>1</mn></msub></math>. The hadronic amplitudes of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>A</mi><mo>/</mo><mi>T</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays are related by the nonperturbative parameters, and the branching ratio predictions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>A</mi><mo>/</mo><mi>T</mi><mo>/</mo><msub><mi>V</mi><mrow><mi>E</mi><mo>,</mo><mi>D</mi></mrow></msub><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> are obtained, and then the branching ratios of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>A</mi><mo stretchy="false">(</mo><mi>A</mi><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><mo stretchy="false">)</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>T</mi><mo stretchy="false">(</mo><mi>T</mi><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><mo stretchy="false">)</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>V</mi><mi>E</mi></msub><mo stretchy="false">(</mo><msub><mi>V</mi><mi>E</mi></msub><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><mo stretchy="false">)</mo><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"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>V</mi><mi>D</mi></msub><mo stretchy="false">(</mo><msub><mi>V</mi><mi>D</mi></msub><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><mo stretchy="false">)</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> are obtained by the narrow width approximation or further considering the width effects. We find that most branching ratios of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>A</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays and many branching ratios of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>A</mi><mo stretchy="false">(</mo><mi>A</mi><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><mo stretchy="false">)</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays are on the order of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup><mi>–</mi><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mo stretchy="false">)</mo></math>, and all branching ratios with the tensor resonance states and the excited vector resonance states are small. Our results could be tested in the future Belle II and LHCb experiments.

Yi Qiao

Jin-Huan Sheng

Yuan-Guo Xu

Ru-Min Wang

Flavor SU(3) analysis of the charmless semileptonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>P</mi><mi>V</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays

We present a measurement of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>u</mi><mi>b</mi></mrow></msub><mo stretchy="false">|</mo></math> from a simultaneous study of the charmless semileptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mo>ℓ</mo></mrow></msub></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>ρ</mi></mrow><mrow><mn>0</mn></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mo>ℓ</mo></mrow></msub></mrow></math>, where <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>. This measurement uses a data sample of 387 million <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover></math> meson pairs recorded by the Belle II detector at the SuperKEKB electron-positron collider between 2019 and 2022. The two decays are reconstructed without identifying the partner <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> mesons. We simultaneously measure the differential branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mn>0</mn></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>−</mo></msup><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"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mn>0</mn></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays as functions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>q</mi><mn>2</mn></msup></math> (momentum transfer squared). From these, we obtain total branching fractions <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mo>ℓ</mo></mrow></msub><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>1.516</mn><mo>±</mo><mn>0.042</mn><mo stretchy="false">(</mo><mrow><mi>stat</mi></mrow><mo stretchy="false">)</mo><mo>±</mo><mn>0.059</mn><mo stretchy="false">(</mo><mrow><mi>syst</mi></mrow><mo stretchy="false">)</mo><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>ρ</mi></mrow><mrow><mn>0</mn></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mo>ℓ</mo></mrow></msub><mo stretchy="false">)</mo><mo>=</mo><mspace linebreak="goodbreak"></mspace><mo stretchy="false">(</mo><mn>1.625</mn><mo>±</mo><mn>0.079</mn><mo stretchy="false">(</mo><mrow><mi>stat</mi></mrow><mo stretchy="false">)</mo><mo>±</mo><mn>0.180</mn><mo stretchy="false">(</mo><mrow><mi>syst</mi></mrow><mo stretchy="false">)</mo><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>. By fitting the measured <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mn>0</mn></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>−</mo></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> partial branching fractions as functions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>q</mi><mn>2</mn></msup></math>, together with constraints on the nonperturbative hadronic contribution from lattice QCD calculations, we obtain <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>u</mi><mi>b</mi></mrow></msub><mo stretchy="false">|</mo><mo>=</mo><mo stretchy="false">(</mo><mn>3.93</mn><mo>±</mo><mn>0.09</mn><mo>±</mo><mn>0.13</mn><mo>±</mo><mn>0.19</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math>. Here, the first uncertainty is statistical, the second is systematic, and the third is theoretical.

I. Adachi

L. Aggarwal

H. Aihara

N. Akopov

A. Aloisio

N. Althubiti

N. Anh Ky

D.M. Asner

H. Atmacan

T. Aushev

V. Aushev

M. Aversano

R. Ayad

V. Babu

H. Bae

S. Bahinipati

P. Bambade

Sw. Banerjee

S. Bansal

M. Barrett

J. Baudot

M. Bauer

A. Baur

A. Beaubien

F. Becherer

J. Becker

J.V. Bennett

F.U. Bernlochner

V. Bertacchi

M. Bertemes

E. Bertholet

M. Bessner

S. Bettarini

B. Bhuyan

F. Bianchi

L. Bierwirth

T. Bilka

D. Biswas

A. Bobrov

D. Bodrov

A. Bolz

J. Borah

A. Boschetti

A. Bozek

M. Bračko

P. Branchini

R.A. Briere

T.E. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

L. Cao

G. Casarosa

C. Cecchi

J. Cerasoli

M.C. Chang

P. Chang

R. Cheaib

P. Cheema

B.G. Cheon

K. Chilikin

K. Chirapatpimol

H.E. Cho

K. Cho

S.J. Cho

S.K. Choi

S. Choudhury

L. Corona

J.X. Cui

F. Dattola

E. De La Cruz-Burelo

S.A. De La Motte

G. De Nardo

M. De Nuccio

G. De Pietro

R. de Sangro

M. Destefanis

S. Dey

R. Dhamija

A. Di Canto

F. Di Capua

J. Dingfelder

Z. Doležal

I. Domínguez Jiménez

T.V. Dong

M. Dorigo

D. Dorner

K. Dort

D. Dossett

S. Dreyer

S. Dubey

K. Dugic

G. Dujany

P. Ecker

M. Eliachevitch

P. Feichtinger

T. Ferber

T. Fillinger

C. Finck

Determination of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>u</mi><mi>b</mi></mrow></msub><mo stretchy="false">|</mo></math> from simultaneous measurements of untagged <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mn>0</mn></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>−</mo></msup><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"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mn>0</mn></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays

Recent measurements of the lepton flavor universality ratios <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>R</mi><mi>K</mi><mrow><mi>μ</mi><mi>e</mi></mrow></msubsup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>R</mi><msup><mi>K</mi><mo>*</mo></msup><mrow><mi>μ</mi><mi>e</mi></mrow></msubsup></math> in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mrow><mo stretchy="false">(</mo><mi>K</mi><mo>,</mo><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">)</mo></mrow><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup><mrow><mo stretchy="false">(</mo><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">)</mo></mrow></math> at LHCb align with the Standard Model predictions, necessitating a search for the complementary decay modes. In this context, we derive the angular decay distributions of the four-fold <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>B</mi><mo stretchy="false">→</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>1270</mn><mo>,</mo><mn>1400</mn><mo stretchy="false">)</mo><mspace linebreak="goodbreak"></mspace><mo stretchy="false">(</mo><mo stretchy="false">→</mo><mi>V</mi><mi>P</mi><mo stretchy="false">)</mo><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> decays, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mn>1</mn></msub></math> is an axial-vector meson, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>V</mi><mo>=</mo><mi>ρ</mi><mo>,</mo><msup><mi>K</mi><mo>*</mo></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>P</mi><mo>=</mo><mi>K</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>π</mi></mrow></math>. Considering the weak effective Hamiltonian with vector and axial-vector new physics operators, and employing the helicity formalism, we obtain the four-dimensional differential decay distributions and extract various physical observables. These include differential branching ratios, lepton forward-backward asymmetry, forward-backward asymmetry for transversely polarized <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mn>1</mn></msub></math> meson, longitudinal and transverse polarization fractions of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mn>1</mn></msub></math> meson, and normalized angular coefficients with longitudinally and transversely polarized final state vector meson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>V</mi></math>, in the cascade decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mn>1</mn></msub><mo stretchy="false">→</mo><mi>V</mi><mi>P</mi></math>. Based on the latest global fit analysis data for all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi></math> transitions, we predict the results of these observables in various bins of the square of the momentum transfer <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><msup><mi>q</mi><mn>2</mn></msup><mo stretchy="false">)</mo></math>. Our findings indicate that these physical observables are not only sensitive to new physics but also can differentiate between various new physics scenarios in certain kinematical regions. The precise measurements of these observables in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>K</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1270</mn><mo>,</mo><mn>1400</mn><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mo stretchy="false">→</mo><mi>V</mi><mi>P</mi><mo stretchy="false">)</mo><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> decays in current and future experiments will provide opportunities for complementary searches for physics beyond the Standard Model in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> decays.

Pakistan

Faisal Munir Bhutta

Canada

Abdur Rehman

M. Jamil Aslam

Ishtiaq Ahmed

Saadi Ishaq

Angular observables of the four-fold <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>K</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1270</mn><mo>,</mo><mn>1400</mn><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mo stretchy="false">→</mo><mi>V</mi><mi>P</mi><mo stretchy="false">)</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> decays in and beyond the Standard Model

The hyperon potential, particularly its behavior at high densities, is crucial for resolving the “hyperon puzzle” in neutron stars and for advancing our understanding of the strong interactions between strange and non-strange particles in high baryon density environments. Using the hadronic transport model AMPT-HC, hypernucleus-nucleus collision is studied. It is found that at beam energies below the threshold for hyperon production, the hyperon elliptic flow exhibits noticeable asymmetry between the positive and negative rapidity regions and is sensitive to the strength of the hyperon potential, especially in the large negative rapidity region. One can extract the hyperon potential approximately twice the saturation density based on the hyperon elliptic flow in the negative rapidity region, and the hyperon potential around the saturation density based on the hyperon elliptic flow in the positive rapidity region.

Gao-Chan Yong

Probing Λ potential via its <italic>v</italic> <inf>2</inf> flow in hypernuclei-induced reaction

This brief review is dedicated to the memory of Maxim V. Polyakov and his pioneering contributions to pentaquark physics. We focus on his seminal 1997 work with Diakonov and Petrov that predicted the ${\mit \Theta }^+$ pentaquark, a breakthrough that initiated an intense period of research in hadron physics. The field faced a significant setback when the CLAS Collaboration at Jefferson Lab reported null results in 2006, leading to a dramatic decline in light-pentaquark research. Nevertheless, Maxim maintained his scientific conviction, supported by continued positive signals from the DIANA and LEPS collaborations. Through recent experimental findings on the ${\mit \Theta }^+$ and the nucleon-like resonance $N^*(1685)$, we examine how Polyakov’s theoretical insights, particularly the prediction of a narrow width (${\mit \Gamma } \approx 0.5$–$1.0$ MeV), remain relevant to our understanding of the ${\mit \Theta }^+$ light pentaquark. Abstract Published by the Jagiellonian University 2025 authors

South Korea

H.-Ch. Kim

Pentaquarks and Maxim V. Polyakov

A search is presented for the pair production of new heavy resonances, each decaying into a top quark (t) or antiquark and a gluon (g). The analysis uses data recorded with the CMS detector from proton–proton collisions at a center-of-mass energy of 13 $$\,\text {Te}\hspace{-.08em}\text {V}$$ at the LHC, corresponding to an integrated luminosity of 138 $$\,\text {fb}^{-1}$$ . Events with one muon or electron, multiple jets, and missing transverse momentum are selected. After using a deep neural network to enrich the data sample with signal-like events, distributions in the scalar sum of the transverse momenta of all reconstructed objects are analyzed in the search for a signal. No significant deviations from the standard model prediction are found. Upper limits at 95% confidence level are set on the product of cross section and branching fraction squared for the pair production of excited top quarks in the $$\text {t}^{*} \rightarrow {\text {t}} {\text {g}} $$ decay channel. The upper limits range from 120 to 0.8 $$\,\text {fb}$$ for a $$\text {t}^{*} $$ with spin-1/2 and from 15 to 1.0 $$\,\text {fb}$$ for a $$\text {t}^{*} $$ with spin-3/2. These correspond to mass exclusion limits up to 1050 and 1700 $$\,\text {Ge}\hspace{-.08em}\text {V}$$ for spin-1/2 and spin-3/2 $$\text {t}^{*} $$ particles, respectively. These are the most stringent limits to date on the existence of $$\text {t}^{*} \rightarrow {\text {t}} {\text {g}} $$ resonances.

Armenia

A. Hayrapetyan

A. Tumasyan

Austria

W. Adam

J. Andrejkovic

L. Benato

T. Bergauer

S. Chatterjee

K. Damanakis

M. Dragicevic

P. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

T. Laer

P. Mechelen

N. Breugelmans

J. D’Hondt

S. Dansana

A. Moor

M. Delcourt

F. Heyen

S. Lowette

I. Makarenko

D. Müller

S. Tavernier

M. Tytgat

G. Onsem

S. Putte

D. Vannerom

B. Bilin

B. Clerbaux

A. Das

I. Bruyn

G. Lentdecker

H. Evard

L. Favart

P. Gianneios

J. Jaramillo

A. Khalilzadeh

F. Khan

K. Lee

A. Malara

S. Paredes

M. Shahzad

L. Thomas

M. Bemden

C. Velde

P. Vanlaer

M. Coen

D. Dobur

Search for pair production of heavy particles decaying to a top quark and a gluon in the lepton+jets final state in proton–proton collisions at $$\sqrt{s}=13\,\text {Te}\hspace{-.08em}\text {V} $$