We investigate charge-balance functions for pion, kaon, and proton pairs in proton-proton (pp) collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn></mrow></math> TeV using Monte Carlo models, pythia8, and epos-lhc, with transverse spherocity to classify event topology and charged-particle multiplicity to select system size. Simulations with pythia8 and epos-lhc reveal that balance-function widths in rapidity and azimuthal angle depend on multiplicity and event shape. In pythia8, widths decrease monotonically with multiplicity, consistent with local charge conservation in a fragmentation-dominated scenario. In contrast, the epos-lhc model, especially when using the core corona implementation, exhibits a more intricate response, where the combined effects of hydrodynamic radial flow and longitudinal diffusion result in narrower azimuthal correlations and broader rapidity correlations. These features are characteristic signatures of collective dynamics, similar to those observed in heavy-ion collisions. Events with low spherocity, which are jetlike in nature, exhibit significantly narrower balance-function widths compared to isotropic events with high spherocity, illustrating that event-shape selection provides clear sensitivity to the underlying dynamics of particle production in pp collisions. The species dependence and event-shape sensitivity of the balance-function widths provide information about the hadronization dynamics and collectivity in small systems. These results demonstrate that multidimensional, particle-species-dependent balance-function measurements can disentangle the underlying mechanisms of charge correlations and mediumlike behavior in high-multiplicity pp collisions.

Italy

Subash Chandra Behera

Arvind Khuntia

System-size and event-shape dependence of particle-identified balance functions in proton-proton collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn></mrow></math> TeV using PYTHIA 8 and EPOS models

Several possible excesses around $ 95 $ GeV hint at an additional light scalar beyond the Standard Model. We examine the capability of the Circular Electron-Positron Collider (CEPC) to test this hypothesis in the Higgs-strahlung channel $ e^{+}e^{-} \to ZS $ with $ Z \to\mu^{+}\mu^{-} $ and $ S \to\tau^{+}\tau^{-} $ . A full detector simulation shows that the optimal center-of-mass energy for studying the 95 GeV light scalar is 210 GeV. A deep neural network classifier reduces the luminosity required for discovery by half. At $ L = 20\; \mathrm{ab}^{-1} $ , the $ 5\sigma $ sensitivity of the CEPC to the signal strength $ \mu_{\tau\tau}^{ZS} $ reaches 0.016 and 0.020 for $ \sqrt{s} = 210 $ GeV and 240 GeV, respectively. The corresponding thresholds for a 5% precision measurement are $ \mu_{\tau\tau}^{ZS} \gt 0.10 $ and $ \gt 0.12 $ . At $ \sqrt{s}=210 $ GeV (240 GeV), the $ 5\sigma $ coverage of all N2HDM-Flipped samples with $ \chi^2_{h_{95}} \lt 7.82 $ requires $ L=800\ \mathrm{fb}^{-1} $ (1.22 $ \mathrm{ab}^{-1} $ ). These results establish a 210 GeV run, augmented by machine-learning selection, as the most efficient strategy to confirm or refute the 95 GeV excess at future lepton colliders.

China

Yabo Dong

Manqi Ruan

Kun Wang

Haijun Yang

Jingya Zhu

Testing a 95 GeV Scalar at the CEPC with Machine Learning * This work was supported by the National Natural Science Foundation of China under Grant No. 12275066 and by the startup research funds of Henan University. The work of K. Wang was also supported by the Open Project of the Shanghai Key Laboratory of Particle Physics and Cosmology under Grant No. 22DZ2229013-3. The work of M. Ruan was also supported by the National Key Program for S&T Research and Development under Contract No. 2024YFA1610603. The work of H. Yang was also supported by the National Natural Science Foundation of China under Grant No. W2441004.

The Circular Electron Positron Collider (CEPC) is designed to operate at key center-of-mass energies: 91.2 GeV as a $\textit{Z}$ factory for precision $\textit{Z}$ boson studies, ≈ 160 GeV at the threshold for $\textit{W}$ boson pair production, and 240 GeV as a Higgs factory for copious Higgs boson production. It can be upgraded to 360 GeV (CEPC-360 GeV) for enabling top quark-antiquark ( $ t\bar{t}$ ) pair production. Beyond enabling high-precision measurements of the Standard Model (SM), CEPC-360 GeV is uniquely positioned to perform searches for new physics beyond the SM (BSM), serving as a valuable complement to hadron colliders. This paper presents a sensitivity study on the direct pair production of staus and smuons at the CEPC with $ \sqrt{s}$ = 360 GeV, conducted via full Monte Carlo simulation. Under the assumptions of 1.0 ab$^{−1}$ integrated luminosity and a flat 5% systematic uncertainty, CEPC-360 GeV could potentially discover the combined production of left-handed and right-handed staus up to a mass of 170 GeV (if they exist) or up to 169 for pure left-handed staus and 162 GeV for pure right-handed staus. For direct smuon production, the discovery potential reaches up to 178 GeV under the same conditions.

Feng Lyu

Jiarong Yuan

Huajie Cheng

Jianxiong Wang

Rabia Hameed

Da Xu

Xuai Zhuang

Search potential for direct slepton pair production at the CEPC with ${ \sqrt{\boldsymbol s}}$ = 360 GeV * Supported by the State Key Program of National Natural Science of China (2018YFA0404000, 12135013)

Neutrino oscillation experiments have confirmed that neutrinos are massive particles and that lepton flavors are mixed. To explain the observed lepton mass spectra and flavor mixing patterns, flavor symmetry plays a crucial and unique role. In this paper, we propose a useful symmetry-breaking scheme by applying $S_{3L} \times S_{3R} \rightarrow $ $ S_{2L} \times S_{2R} \rightarrow \emptyset$ within both charged-lepton and neutrino sectors at the mass-matrix level. For the three distinct residual subgroups $S_{2L}^{(23)} \times S_{2R}^{(23)}$ , $S_{2L}^{(13)} \times S_{2R}^{(13)}$ , and $S_{2L}^{(12)} \times S_{2R}^{(12)}$ that are under consideration, we systematically analyze the various parameterizations of the lepton mass matrices. It is shown that all three scenarios are in good agreement with current neutrino oscillation data. Notably, within the latest best-fit values of neutrino oscillation parameters, the predicted values of the Dirac CP-violating phase $\textit{δ}$ are $294.6^\circ$ , $302.3^\circ$ , and $287.0^\circ$ , respectively. To further assess the viability of the model, a comprehensive numerical analysis is performed by utilizing neutrino oscillation parameters at the $3\sigma$ level. It is found that the allowed ranges of $\textit{δ}$ are $281.2^\circ \rightarrow 338.7^\circ$ , $287.0^\circ \rightarrow 342.2^\circ$ , and $282.7^\circ \rightarrow 297.0^\circ$ , which all fall within its $3\sigma$ range. These results indicate that the proposed symmetry-breaking scheme $S_{3L} \times S_{3R} \rightarrow S_{2L} \times S_{2R} \rightarrow \emptyset$ can naturally explain the realistic lepton mass hierarchy and mixing pattern, thereby providing valuable theoretical perspectives for future research.

Chang-Qi Hu

Chun-Yuan Li

Xiao Liang

Xing-Hua Yang

Dai-Xing Zhang

Further study on lepton mass spectra and flavor mixing with $\textit{S}$ 3$\textit{L}$ × $\textit{S}$ 3$\textit{R}$ flavor symmetry * Supported in part by the National Natural Science Foundation of China (12105162, 12305106), the Natural Science Foundation of Shandong Province (ZR2021QA058, ZR2021QA040) and the Youth Innovation Technology Project of Higher School in Shandong Province (2023KJ146)

A measurement of $\textit{CP}$ asymmetry in $$ {D}^0\to {K}_{\textrm{S}}^0{K}_{\textrm{S}}^0 $$ decays is reported, based on a data sample of proton-proton collisions collected with the LHCb detector in 2024 at a centre-of-mass energy of 13.6 TeV, corresponding to an integrated luminosity of 6.2 fb . The $$ {D}^0\to {K}_{\textrm{S}}^0{\pi}^{+}{\pi}^{-} $$ decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated $\textit{CP}$ asymmetry for the $$ {D}^0\to {K}_{\textrm{S}}^0{K}_{\textrm{S}}^0 $$ mode is measured to be

Netherlands

R. Aaij

United Kingdom

A. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A. Adefisoye

Spain

B. Adeva

M. Adinolfi

Sweden

P. Adlarson

France

C. Agapopoulou

C. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Poland

M. Akthar

P. Albicocco

Germany

J. Albrecht

Lithuania

R. Aleksiejunas

F. Alessio

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J. Amey

Y. Amhis

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

C. Arata

F. Archilli

Z. Areg

M. Argenton

Costa Rica

S. Arguedas Cuendis

L. Arnone

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

J. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J. Back

P. Baladron Rodriguez

V. Balagura

A. Balboni

W. Baldini

Z. Baldwin

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I. Barbosa

R. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

S. Bashir

B. Batsukh

P. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I. Bediaga

N. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

C. Betancourt

F. Betti

J. Bex

Ia. Bezshyiko

Ukraine

O. Bezshyyko

J. Bhom

M. Bieker

N. Biesuz

A. Biolchini

M. Birch

F. Bishop

A. Bitadze

A. Bizzeti

Measurement of $\textit{CP}$ asymmetry in $$ {D}^0\to {K}_{\textrm{S}}^0{K}_{\textrm{S}}^0 $$ decays with Run 3 data

We propose an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>AdS</mi><mo>×</mo><mi mathvariant="normal">S</mi></mrow></math> factorization formula at the level of the generating function for correlators with arbitrary Kaluza-Klein configurations and implement it in the supergravity limit of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">N</mi><mo>=</mo><mn>4</mn></mrow></math> supersymmetric Yang-Mills theory. By incorporating this mechanism into Mellin space bootstrap, together with an observed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mn>2</mn></msub></math> symmetry under <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>AdS</mi><mo stretchy="false">↔</mo><mi mathvariant="normal">S</mi></mrow></math>, we manage to simultaneously work out unified formulas both for all five-point half-BPS correlators and for all four-point correlators with one superdescendant. This <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>AdS</mi><mo>×</mo><mi mathvariant="normal">S</mi></mrow></math> bootstrap method is directly applicable to generic multipoint computation at tree level.

Portugal

Bruno Fernandes

Vasco Gonçalves

Zhongjie Huang

Yichao Tang

Joao Vilas Boas

Ellis Ye Yuan

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>AdS</mi><mo stretchy="false">×</mo><mi mathvariant="normal">S</mi></mrow></math> Mellin Bootstrap, Hidden 10D Symmetry and Five-Point Kaluza-Klein Functions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">N</mi><mo>=</mo><mn>4</mn></mrow></math> Supersymmetric Yang-Mills Theory

Recently, many new excited states of heavy mesons have been discovered in recent experiments, including radially excited states. The production processes of these states from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub></math> meson have drawn significant interest. In this paper, we use the covariant light-front approach to study the nonleptonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub></math> meson decays to the first radially excited states <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math>. Our results reveal that many channels exhibit large branching ratios in the range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><mi>–</mi><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, even up to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math> for individual channels, which are detectable by current experiments. Our predictions for the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">→</mo><msubsup><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>π</mi><mo>,</mo><mi>ρ</mi><mo>,</mo><msup><mi>K</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup><mo stretchy="false">)</mo></math> are larger than those given by the Bethe-Salpeter (BS) equation method, but agree well with the relativistic quark mode (RQM) and the relativistic independent quark model (RIQM) calculations. For comparison, we also present the branching ratios of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">→</mo><msubsup><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>π</mi><mo>,</mo><mi>ρ</mi><mo>,</mo><msup><mi>K</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup><mo stretchy="false">)</mo></math>, which are comparable with other theoretical results and the data. Although the branching ratios of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">→</mo><msubsup><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>ρ</mi><mo>,</mo><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">)</mo></math> are much larger than those of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">→</mo><msubsup><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>ρ</mi><mo>,</mo><msup><mi>K</mi><mo>*</mo></msup><mo stretchy="false">)</mo></math>, the polarization properties between them are similar, that is, the longitudinal polarization fractions are dominant and can amount roughly to 90%.

Zhi-Jie Sun

Yong-Jin Sun

Zhi-Qing Zhang

You-Ya Yang

Si-Yang Wang

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> production in nonleptonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub></math> weak decays

Lorentzian gravitational path integral for the Gauss-Bonnet gravity in 4$\textit{D}$ is studied in the mini-superspace ansatz for metric. The gauge-fixed path-integral for Robin boundary choice is computed exactly using $\textit{Airy}$-functions, where the dominant contribution comes from No-boundary geometries. The lapse integral is further analysed using saddle-point methods to compare with exact results. Picard-Lefschetz methods are utilized to find the $\textit{relevant}$ complex saddles and deformed contour of integration, thereby using WKB method to compute the integral along the deformed contour in the saddle-point approximation. However, their successful application is possible only when system is devoid of degeneracies, which in present case appear in two types: $\textit{type-1}$ where the flow-lines starting from neighbouring saddles overlap leading to ambiguities in deciding the $\textit{relevance}$ of saddles, $\textit{type-2}$ where saddles merge for specific choices of boundary parameters leading to failure of WKB. Overcoming degeneracies using artificial $\textit{defects}$ introduces ambiguities due to the choice of $\textit{defects}$ involved. Corrections from quantum fluctuations of scale-factor overcome degeneracies only partially (lifts $\textit{type-2}$ completely with partial resolution of $\textit{type-1}$ ), with the residual lifted fluently by complex deformation of ($\textit{G}$ℏ). $\textit{Anti-linear}$ symmetry present in various forms in the lapse action is the reason behind all the $\textit{type-1}$ degeneracies. Any form of $\textit{defect}$ or $\textit{deformation}$ breaking anti-linearity resolves $\textit{type-1}$ degeneracies, indicating complex deformation of ($\textit{G}$ℏ) as an ideal choice. Compatibility with the KSW criterion is analyzed after symmetry breaking. Complex deformation of ($\textit{G}$ℏ) modifies the KSW criterion, imposing a strong constraint on the deformation if No-boundary geometries are required to be always KSW-allowed.

India

Manishankar Ailiga

Shubhashis Mallik

Gaurav Narain

Resolving degeneracies in complex $\textit{ℝ}$ × $\textit{S}$

Motivated by the successful application of Heavy Quark Effective Field Theory in describing decays from heavy to light mesons, this work explores its applicability to the semileptonic decays of charmed mesons. So in this paper we investigate the <math altimg='si38.svg'><mrow><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>&#8594;</mo><msup><mi>&#951;</mi><mrow><mo>(</mo><mo>&#8242;</mo><mo>)</mo></mrow></msup><msup><mi>&#8467;</mi><mo>+</mo></msup><msub><mi>&#957;</mi><mi>&#8467;</mi></msub></mrow></math> transition form factors using the light-cone sum rules approach within the framework of heavy-quark effective field theory. To address the large uncertainties arsing from the <italic>&#951;</italic> (&#8242;)-meson twist-3 distribution amplitudes, we employ the right-handed chiral correlation function. By applying the converging simplified series expansion method, we extrapolate the form factors to the entire physical <italic>q</italic> 2-region. Our analysis yields the branching fractions precise predictions for semi-leptonic decays <math altimg='si38.svg'><mrow><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>&#8594;</mo><msup><mi>&#951;</mi><mrow><mo>(</mo><mo>&#8242;</mo><mo>)</mo></mrow></msup><msup><mi>&#8467;</mi><mo>+</mo></msup><msub><mi>&#957;</mi><mi>&#8467;</mi></msub></mrow></math> with : <math altimg='si49.svg'><mrow><mi mathvariant='script'>B</mi><mrow><mo>(</mo><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>&#8594;</mo><mi>&#951;</mi><msup><mi>&#8467;</mi><mo>+</mo></msup><msub><mi>&#957;</mi><mi>&#8467;</mi></msub><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><mn>2</mn><mo>.</mo><msubsup><mn>300</mn><mrow><mo>&#8722;</mo><mn>0.227</mn></mrow><mrow><mo>+</mo><mn>0.230</mn></mrow></msubsup><mo>%</mo></mrow></math> ( <math altimg='si39.svg'><mrow><mi>&#8467;</mi><mo linebreak='goodbreak'>=</mo><mi>e</mi></mrow></math>) and <math altimg='si50.svg'><mrow><mn>2</mn><mo>.</mo><msubsup><mn>249</mn><mrow><mo>&#8722;</mo><mn>0.206</mn></mrow><mrow><mo>+</mo><mn>0.209</mn></mrow></msubsup><mo>%</mo></mrow></math> ( <math altimg='si51.svg'><mrow><mi>&#8467;</mi><mo linebreak='goodbreak'>=</mo><mi>&#956;</mi></mrow></math>); <math altimg='si52.svg'><mrow><mi mathvariant='script'>B</mi><mrow><mo>(</mo><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>&#8594;</mo><msup><mi>&#951;</mi><mo>&#8242;</mo></msup><msup><mi>&#8467;</mi><mo>+</mo></msup><msub><mi>&#957;</mi><mi>&#8467;</mi></msub><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>861</mn><mrow><mo>&#8722;</mo><mn>0.093</mn></mrow><mrow><mo>+</mo><mn>0.095</mn></mrow></msubsup><mo>%</mo></mrow></math> ( <math altimg='si39.svg'><mrow><mi>&#8467;</mi><mo linebreak='goodbreak'>=</mo><mi>e</mi></mrow></math>) and <math altimg='si53.svg'><mrow><mn>0</mn><mo>.</mo><msubsup><mn>821</mn><mrow><mo>&#8722;</mo><mn>0.080</mn></mrow><mrow><mo>+</mo><mn>0.082</mn></mrow></msubsup><mo>%</mo></mrow></math> ( <math altimg='si51.svg'><mrow><mi>&#8467;</mi><mo linebreak='goodbreak'>=</mo><mi>&#956;</mi></mrow></math>). The derived lepton flavor universality ratios <math altimg='si54.svg'><mrow><msubsup><mi>R</mi><mrow><mi>&#956;</mi><mo>,</mo><mi>e</mi></mrow><mi>&#951;</mi></msubsup><mo linebreak='goodbreak'>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>977</mn><mrow><mo>&#8722;</mo><mn>0.006</mn></mrow><mrow><mo>+</mo><mn>0.008</mn></mrow></msubsup></mrow></math> and <math altimg='si55.svg'><mrow><msubsup><mi>R</mi><mrow><mi>&#956;</mi><mo>,</mo><mi>e</mi></mrow><msup><mi>&#951;</mi><mo>&#8242;</mo></msup></msubsup><mo linebreak='goodbreak'>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>953</mn><mrow><mo>&#8722;</mo><mn>0.009</mn></mrow><mrow><mo>+</mo><mn>0.011</mn></mrow></msubsup></mrow></math> are consistent with lasted BESIII experimental measurements. Additionally, the forward-backward asymmetry parameters <math altimg='si56.svg'><mrow><mrow><mo>&#9001;</mo><msubsup><mi mathvariant='script'>A</mi><mrow><mrow><mi mathvariant='normal'>F</mi></mrow><mi>B</mi></mrow><mi>&#951;</mi></msubsup><mo>&#9002;</mo></mrow><mo linebreak='goodbreak'>=</mo><mo>&#8722;</mo><mn>0</mn><mo>.</mo><msubsup><mn>034</mn><mrow><mo>&#8722;</mo><mn>0.003</mn></mrow><mrow><mo>+</mo><mn>0.003</mn></mrow></msubsup></mrow></math> and <math altimg='si57.svg'><mrow><mrow><mo>&#9001;</mo><msubsup><mi mathvariant='script'>A</mi><mrow><mrow><mi mathvariant='normal'>F</mi></mrow><mi>B</mi></mrow><msup><mi>&#951;</mi><mo>&#8242;</mo></msup></msubsup><mo>&#9002;</mo></mrow><mo linebreak='goodbreak'>=</mo><mo>&#8722;</mo><mn>0</mn><mo>.</mo><msubsup><mn>073</mn><mrow><mo>&#8722;</mo><mn>0.008</mn></mrow><mrow><mo>+</mo><mn>0.007</mn></mrow></msubsup></mrow></math> suggest that no significant violation of lepton flavor universality in this decay process.

Ruiyu Zhou

Hai-Bing Fu

Yi Zhang

Wei Cheng

Probing <math altimg='si38.svg'><mrow><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>&#8594;</mo><msup><mi>&#951;</mi><mrow><mo>(</mo><mo>&#8242;</mo><mo>)</mo></mrow></msup><msup><mi>&#8467;</mi><mo>+</mo></msup><msub><mi>&#957;</mi><mi>&#8467;</mi></msub></mrow></math> semileptonic decay within LCSR under chiral heavy quark effective field theory

We develop a strategy for computing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>K</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mi>s</mi></msub><mo stretchy="false">→</mo><mi>γ</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> decay amplitudes using lattice QCD (where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mo>ℓ</mo><mo>±</mo></msup></math> are charged leptons). We focus on those terms which contain complex contributions to the amplitude, due to on-shell intermediate states propagating between the weak operator and electromagnetic current(s). Such terms, which are generally estimated using model calculations and represent significant uncertainties in the phenomenological predictions for these decays, cannot be computed using standard lattice QCD techniques. It has recently been shown that such contributions can be computed using spectral density methods and our proposed strategy, which we discuss in detail, is built on this approach. The complex contributions include the “charming penguins” [matrix elements of the current-current operators <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>O</mi><mn>1</mn><mrow><mo stretchy="false">(</mo><mi>c</mi><mo stretchy="false">)</mo></mrow></msubsup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>O</mi><mn>2</mn><mrow><mo stretchy="false">(</mo><mi>c</mi><mo stretchy="false">)</mo></mrow></msubsup></math> defined in Eq. (6) below], in which the charm-quark loop can propagate long distances, particularly close to the region of charmonium resonances. They also include the contributions from the chromomagnetic operator [<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>O</mi><mn>8</mn></msub></math> in standard notation, defined in Eq. (8) below]. We discuss the renormalization of the ultraviolet divergences, and in particular those which arise due to “contact” terms, and explain how those which appear as inverse powers of the lattice spacing can be subtracted nonperturbatively. We apply the spectral density methods in an instructive exploratory computation of the charming penguin diagram in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>K</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> decays in which the virtual photon is emitted from the charm-quark loop [the diagram in Fig. 1(a) below] and discuss the prospects and strategies for the reliable determination of the amplitudes in future dedicated computations; computations which are, however, beyond the scope of the present paper.

Roberto Frezzotti

Nazario Tantalo

Giuseppe Gagliardi

Vittorio Lubicz

Guido Martinelli

Chris T. Sachrajda

Francesco Sanfilippo

Silvano Simula

Luca Silvestrini

Theoretical framework for lattice QCD computations of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>K</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mi>s</mi></msub><mo stretchy="false">→</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup><mi>γ</mi></math> decays rates, including contributions from charming penguin diagrams