Using the Kreuzer-Skarke database of 4-dimensional reflexive polytopes, we systematically constructed a new database of orientifold Calabi-Yau threefolds with h 1,1(X) ≤ 12. Our approach involved non-trivial ℤ2 involutions, incorporating both divisor exchanges and multi-divisor reflections acting on the Calabi-Yau threefolds. Each proper involution results in an orientifold Calabi-Yau threefolds and we constructed 320, 386, 067 such examples. We developed a novel algorithm that significantly reduces the complexity of determining all the fixed loci under the involutions, and clarifies the types of O-planes. Our results show that under proper involutions, the majority of cases end up with O3/O7-plane systems, and most of these further admit a naive Type IIB string vacua. Additionally, a new type of free action was determined. We also computed the smoothness and the splitting of Hodge numbers in the ℤ2-orbifold limit for these orientifold Calabi-Yau threefolds.

China

Xu Cao

Hongfei Gao

Xin Gao

Orientifold Calabi-Yau threefolds: divisor exchanges and multi-reflections

The self-polarization of relativistic electrons or positrons moving in a magnetic field at a storage ring occurs through the emission of spin-flip synchrotron radiation, known as the Sokolov-Ternov effect. The resulting transverse polarizations of the colliding electrons and positrons, away from the depolarization resonances, allow for precise investigation of the spin entangled hyperon-antihyperon pairs via virtual photon or charmonium decay. The feasibility study reveals a promising increase in the statistical sensitivity of the <math><mi>C</mi><mi>P</mi></math> violation signal after considering the transverse polarizations of the lepton beams.

Yu-Tie Liang

Rong-Gang Ping

Production and decay of hyperons in a transversely polarized electron-positron collider

We investigate the exclusive  $$J/\psi $$  <math> <mrow> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> </mrow> </math>   production at the future Electron-ion collider in China by utilizing the eSTARlight event generator. We model the cross-section and kinematics by fitting to the world data of  $$J/\psi $$  <math> <mrow> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> </mrow> </math>   photoproduction. Projected statistical uncertainties on  $$J/\psi $$  <math> <mrow> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> </mrow> </math>   production are based on the design of a central detector, which consists of a tracker and vertex subsystem. The precision of the pseudo-data allows us to probe the near-threshold mechanism, e.g. the re-scattering effect. The significance of the forward amplitudes is discussed as well. The design and optimization of the detector enhance the potential for exploring the near-threshold region and the realm of high four-momentum transfer squared, which is of particular interest on several physics topics.

Xue Wang

Aiqiang Guo

Li Gong

Xiao-Shen Kang

Jia-Jun Wu

Ya-Ping Xie

Exclusive charmonium production at the electron-ion collider in China

Inspired by the recent precise data, we perform model-independently an isospin decomposition of the timelike octet baryons electromagnetic form factors. As noted in our previous work, the relative magnitude of isoscalar and isovector component is determined with the input of data on various isospin channels. Herein we further assert that their relative phase can be constraint by the phase difference of oscillatory modulation of effective form factors between isospin channels. The framework is extended to analyze the data of differential cross sections and applied to the form factors of nucleon and hyperons with detail and isospin non-conservation of charmonium decay into baryon-anti-baryon as well. We address that isospin analysis is meaningful when the isospin broken scale is compared to or smaller than the uncertainties of data.

Jian-Ping Dai

Germany

Horst Lenske

Data driven isospin analysis of timelike octet baryons electromagnetic form factors and charmonium decay into baryon-anti-baryon

We estimate the impact of asymmetry measurements of Deeply Virtual Compton Scattering (DVCS) with transversely polarized proton beam taken at a future Electron Ion Collider in China (EicC) on the extraction of Compton Form Factors (CFFs). The CFFs extracted from an analysis based on artificial neural-network approach are reweighted by means of pseudo-data generated in the expected kinematic region of EicC. We find a remarkable improvement in the extraction of CFF  $$Im {\mathcal E}$$  <math> <mrow> <mi>I</mi> <mi>m</mi> <mi>E</mi> </mrow> </math>  , especially at the range of parton momentum fraction  $$x \sim $$  <math> <mrow> <mi>x</mi> <mo>∼</mo> </mrow> </math>   0.01, thus hinting for a future experimental probe of the parton orbital angular momentum. This work casts a glance at a practical implementation of Bayesian reweighting method on CFFs’ impact study.

Jinlong Zhang

Accessing compton form factors at the electron ion collider in China: an impact study on  $${\textbf {Im}} {\mathcal E}$$  <math> <mrow> <mi>Im</mi> <mi>E</mi> </mrow> </math>

A striking feature of the timelike nucleon electromagnetic form factors, investigated in <math><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo>→</mo><mi>N</mi><mover><mi>N</mi><mo>¯</mo></mover></math> annihilation reactions, is the modulation by local structures of small magnitude and oscillatory form, showing up above the <math><mi>N</mi><mover><mi>N</mi><mo>¯</mo></mover></math> threshold. Starting from an isospin decomposition of the proton and neutron form factors it is shown that such structures are the natural consequence of the interference of a large and a small amplitude, resulting in a sinusoidal behavior as a function of the “invariant energy” if the relative phase shift varies with energy. Thus, periodic oscillations superimposed on a smooth background will be observed. In this scenario, the equal size of the modulation for neutrons and protons (discovered by recent BESIII data) implies the particular isoscalar or isovector nature of these local structures, or their orthogonal interference. Hence, it specifies their origin as excited vector mesons whose widths are tied to the modulation frequency. We clarify that the phase difference of the modulation between neutrons and protons as BESIII data found, but not the modulation itself, is the evidence of an imaginary part of the timelike nucleon electromagnetic form factors, which is associated with the rescattering processes.

Timelike nucleon electromagnetic form factors: All about interference of isospin amplitudes

The discovery of a charged strange hidden-charm state  $$Z_{cs}$$  <math> <msub> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> </msub> </math>  (3985) implies another higher  $$Z^*_{cs}$$  <math> <msubsup> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> <mo>∗</mo> </msubsup> </math>   state coupling to  $${\bar{D}}_s^{*-}D^{*0} + c.c$$  <math> <mrow> <msubsup> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> <mrow> <mrow></mrow> <mo>∗</mo> <mo>-</mo> </mrow> </msubsup> <msup> <mi>D</mi> <mrow> <mrow></mrow> <mo>∗</mo> <mn>0</mn> </mrow> </msup> <mo>+</mo> <mi>c</mi> <mo>.</mo> <mi>c</mi> </mrow> </math>   under the heavy quark spin symmetry. In this paper we discuss a possible hunt for it with data taken at existing facilities. We point out a hint for  $$Z^*_{cs}$$  <math> <msubsup> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> <mo>∗</mo> </msubsup> </math>   in the data of  $${\bar{B}}_s^0 \rightarrow J/\psi K^- K^+$$  <math> <mrow> <msubsup> <mover> <mrow> <mi>B</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> <mn>0</mn> </msubsup> <mo>→</mo> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <msup> <mi>K</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   at LHCb, though weak, in line with the production mechanism of pentaquark  $$P_c$$  <math> <msub> <mi>P</mi> <mi>c</mi> </msub> </math>  . We also study the triangular singularity which would possibly enhance the production of  $$Z^*_{cs}$$  <math> <msubsup> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> <mo>∗</mo> </msubsup> </math>   in electron-positron collision. Surprisingly, the production rate of  $$Z^*_{cs}$$  <math> <msubsup> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> <mo>∗</mo> </msubsup> </math>   is expected to be maximum at the  $$e^+ e^-$$  <math> <mrow> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>-</mo> </msup> </mrow> </math>   center of mass energy of 4.648 GeV, which is lower than 4.681 GeV for  $$Z_{cs}$$  <math> <msub> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> </msub> </math>   due to the inverted coupling hierarchy of  $$D_{s1}{\bar{D}}^* K$$  <math> <mrow> <msub> <mi>D</mi> <mrow> <mi>s</mi> <mn>1</mn> </mrow> </msub> <msup> <mrow> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> </mrow> <mo>∗</mo> </msup> <mi>K</mi> </mrow> </math>   and  $$D_{s2}{\bar{D}}K$$  <math> <mrow> <msub> <mi>D</mi> <mrow> <mi>s</mi> <mn>2</mn> </mrow> </msub> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>K</mi> </mrow> </math>   in the triangle diagrams. Their bottom analogue under heavy quark flavor symmetry is also discussed. Our theoretical analysis would confront with future experiment of LHCb, BESIII, and Bell II.

Zhi Yang

Hunting for the heavy quark spin symmetry partner of  $$Z_{cs}$$  <math> <msub> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> </msub> </math>

Quantum chromodynamics presents a series of exact and approximate symmetries which can be exploited to predict new hadrons from previously known ones. The <math><msub><mi>Z</mi><mi>c</mi></msub><mo>(</mo><mn>3900</mn><mo>)</mo></math> and <math><msub><mi>Z</mi><mi>c</mi></msub><mo>(</mo><mn>4020</mn><mo>)</mo></math>, which have been theorized to be isovector <math><msup><mi>D</mi><mo>*</mo></msup><mover><mi>D</mi><mo>¯</mo></mover></math> and <math><msup><mi>D</mi><mo>*</mo></msup><msup><mover><mi>D</mi><mo>¯</mo></mover><mo>*</mo></msup></math> molecules [<math><msup><mi>I</mi><mi>G</mi></msup><mo>(</mo><msup><mi>J</mi><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>)</mo><mo>=</mo><msup><mn>1</mn><mo>−</mo></msup><mo>(</mo><msup><mn>1</mn><mrow><mo>+</mo><mo>−</mo></mrow></msup><mo>)</mo></math>], are no exception. Here we argue that from SU(3)-flavor symmetry, we should expect the existence of strange partners of the <math><msub><mi>Z</mi><mi>c</mi></msub></math>’s with hadronic molecular configurations <math><msup><mi>D</mi><mo>*</mo></msup><msub><mover><mi>D</mi><mo>¯</mo></mover><mi>s</mi></msub><mo>−</mo><mi>D</mi><msubsup><mover><mi>D</mi><mo>¯</mo></mover><mi>s</mi><mo>*</mo></msubsup></math> and <math><msup><mi>D</mi><mo>*</mo></msup><msubsup><mover><mi>D</mi><mo>¯</mo></mover><mi>s</mi><mo>*</mo></msubsup></math> (or, equivalently, quark content <math><mi>c</mi><mover><mi>c</mi><mo>¯</mo></mover><mi>s</mi><mover><mi>q</mi><mo>¯</mo></mover></math>, with <math><mrow><mrow><mi>q</mi><mo>=</mo><mi>u</mi></mrow></mrow></math>, <math><mrow><mi>d</mi></mrow></math>). The quantum numbers of these <math><msub><mi>Z</mi><mrow><mi>c</mi><mi>s</mi></mrow></msub></math> and <math><msubsup><mi>Z</mi><mrow><mi>c</mi><mi>s</mi></mrow><mo>*</mo></msubsup></math> structures would be <math><mi>I</mi><mo>(</mo><msup><mi>J</mi><mi>P</mi></msup><mo>)</mo><mo>=</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>(</mo><msup><mn>1</mn><mo>+</mo></msup><mo>)</mo></math>. The predicted masses of these partners depend on the details of the theoretical scheme used, but they should be around the <math><msup><mi>D</mi><mo>*</mo></msup><msub><mover><mi>D</mi><mo>¯</mo></mover><mi>s</mi></msub><mo>−</mo><mi>D</mi><msubsup><mover><mi>D</mi><mo>¯</mo></mover><mi>s</mi><mo>*</mo></msubsup></math> and <math><msup><mi>D</mi><mo>*</mo></msup><msubsup><mover><mi>D</mi><mo>¯</mo></mover><mi>s</mi><mo>*</mo></msubsup></math> thresholds, respectively. Moreover, any of these states could be either a virtual pole or a resonance. We show that, together with a possible triangle singularity contribution, such a picture nicely agrees with the very recent BESIII data of the <math><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mo>(</mo><msubsup><mi>D</mi><mi>s</mi><mo>−</mo></msubsup><msup><mi>D</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo>+</mo><msubsup><mi>D</mi><mi>s</mi><mrow><mo>*</mo><mo>−</mo></mrow></msubsup><msup><mi>D</mi><mn>0</mn></msup><mo>)</mo></math>.

Feng-Kun Guo

Spain

Juan Nieves

Manuel Pavon Valderrama

Strange molecular partners of the <math><mrow><msub><mrow><mi>Z</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>(</mo><mn>3900</mn><mo>)</mo></mrow></math> and <math><msub><mi>Z</mi><mi>c</mi></msub><mo>(</mo><mn>4020</mn><mo>)</mo></math>

Recently BESIII collaboration discovered a charged strange hidden-charm state  $$Z_{cs}$$  <math> <msub> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> </msub> </math>  (3985) in the  $$D_s^-D^{*0} + D_s^{*-}D^{0}$$  <math> <mrow> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> <msup> <mi>D</mi> <mrow> <mrow></mrow> <mo>∗</mo> <mn>0</mn> </mrow> </msup> <mo>+</mo> <msubsup> <mi>D</mi> <mi>s</mi> <mrow> <mrow></mrow> <mo>∗</mo> <mo>-</mo> </mrow> </msubsup> <msup> <mi>D</mi> <mn>0</mn> </msup> </mrow> </math>   spectrum. A higher  $$Z'_{cs}$$  <math> <msubsup> <mi>Z</mi> <mrow> <mi>cs</mi> </mrow> <mo>′</mo> </msubsup> </math>   state coupling to  $${\bar{D}}_s^{*-}D^{*0}$$  <math> <mrow> <msubsup> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> <mrow> <mrow></mrow> <mo>∗</mo> <mo>-</mo> </mrow> </msubsup> <msup> <mi>D</mi> <mrow> <mrow></mrow> <mo>∗</mo> <mn>0</mn> </mrow> </msup> </mrow> </math>   is expected by SU(3)-flavor symmetry, and their bottom partners are anticipated by heavy quark flavor symmetry. Here we study the photoproduction of these exotic states and investigate carefully the background from Pomeron exchange. Our results indicate that the maximal photoproduction cross section of strange partner is around 1–2 orders of magnitude smaller than that of the corresponding non-strange states. The possibility of searching for them in future electron-ion colliders (EIC) is briefly discussed.

Photoproduction of strange hidden-charm and hidden-bottom states

The existence of light sterile neutrinos is a long-standing question in particle physics. Several experimental “anomalies” might be explained by introducing eV mass scaled light sterile neutrinos. Many experiments are actively searching for such light sterile neutrinos through neutrino oscillation. For long baseline experiments, the matter effect should be treated carefully for precise calculation of the neutrino oscillation probabilities. However, this is usually time-consuming or analytically complex. In this manuscript, we adopt a Jacobi-like method to diagonalize the Hermitian Hamiltonian matrix and derive analytically simplified neutrino oscillation probabilities for 3 (active) + 1 (sterile)-neutrino mixing for a constant matter density. These approximations can reach a considerably high numerical accuracy while retaining their analytical simplicity and fast computing speed. This would be useful for current and future long baseline neutrino oscillation experiments.

Bao-Biao Yue

Wei Li

Jia-Jie Ling

Fan-Rong Xu

A compact analytical approximation for a light sterile neutrino oscillation in matter Jiajie Ling acknowledges the support from National Key R&D program of China (2018YFA0404103) and National Natural Science Foundation of China (11775315). F. Xu is supported partially by NSFC (11605076), as well as the FRFCU (Fundamental Research Funds for the Central Universities in China) (21616309)