Within a phenomenological diquark fragmentation model, we study the production of doubly charmed tetraquark <math altimg='si1.svg'><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math> via photon-photon fusion at electron-positron colliders. The production of <math altimg='si1.svg'><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math> is divided into two steps: the perturbative production of heavy <math altimg='si2.svg'><mo stretchy='false'>(</mo><mi>c</mi><mi>c</mi><mo stretchy='false'>)</mo></math>-diquark and its nonperturbative hadronization. Two diquark configurations of <math altimg='si3.svg'><mo stretchy='false'>(</mo><mi>c</mi><mi>c</mi><mo stretchy='false'>)</mo><msub><mrow><mo stretchy='false'>[</mo><mmultiscripts><mrow><mi>S</mi></mrow><mrow><mn>1</mn></mrow><none /><mprescripts /><none /><mrow><mn>3</mn></mrow></mmultiscripts><mo stretchy='false'>]</mo></mrow><mrow><mover accent='true'><mrow><mn>3</mn></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></mrow></msub></math> and <math altimg='si4.svg'><mo stretchy='false'>(</mo><mi>c</mi><mi>c</mi><mo stretchy='false'>)</mo><msub><mrow><mo stretchy='false'>[</mo><mmultiscripts><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow><none /><mprescripts /><none /><mrow><mn>1</mn></mrow></mmultiscripts><mo stretchy='false'>]</mo></mrow><mrow><mn>6</mn></mrow></msub></math> are considered, and the <math altimg='si3.svg'><mo stretchy='false'>(</mo><mi>c</mi><mi>c</mi><mo stretchy='false'>)</mo><msub><mrow><mo stretchy='false'>[</mo><mmultiscripts><mrow><mi>S</mi></mrow><mrow><mn>1</mn></mrow><none /><mprescripts /><none /><mrow><mn>3</mn></mrow></mmultiscripts><mo stretchy='false'>]</mo></mrow><mrow><mover accent='true'><mrow><mn>3</mn></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></mrow></msub></math> state dominates the production of <math altimg='si1.svg'><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math>. We discuss two hadronization models of <math altimg='si3.svg'><mo stretchy='false'>(</mo><mi>c</mi><mi>c</mi><mo stretchy='false'>)</mo><msub><mrow><mo stretchy='false'>[</mo><mmultiscripts><mrow><mi>S</mi></mrow><mrow><mn>1</mn></mrow><none /><mprescripts /><none /><mrow><mn>3</mn></mrow></mmultiscripts><mo stretchy='false'>]</mo></mrow><mrow><mover accent='true'><mrow><mn>3</mn></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></mrow></msub></math> intermediate state into the tetraquark <math altimg='si1.svg'><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math>. It is found that it is promising to observe the tetraquark <math altimg='si1.svg'><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math> via photon-photon fusion process both at the Circular Electron Positron Collider (CEPC) and the International Linear Collider (ILC). We find that the cross sections are sensitive to constituent charm quark mass of diquark, and they also have strong dependence on the hadronization models.

China

Jun Jiang

Shi-Yuan Li

Xiao Liang

Yan-Rui Liu

Zong-Guo Si

Zhong-Juan Yang

Production of doubly charmed tetraquark <italic>T</italic> <inf><italic>cc</italic></inf> via photon-photon fusion at electron-positron colliders

<p>We study the next-to-leading order (NLO) electroweak (EW) corrections to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>γ</mi><mi>γ</mi><mo stretchy="false">→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> process in a Pb-Pb ultraperipheral collision (UPC). We find that the EW correction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>δ</mi><msub><mi>σ</mi><mi>EW</mi></msub></math> decreases the total cross section <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>NLO</mi></mrow></msub><mo>=</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>LO</mi></mrow></msub><mo>+</mo><mi>δ</mi><msub><mrow><mi>σ</mi></mrow><mrow><mi>EW</mi></mrow></msub></mrow></math> by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo>−</mo><mn>3</mn><mo>%</mo></mrow></math> at Pb-Pb center-of-mass energy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>. The weak correction plays a significant role whose contribution is about–4 times that of QED. The CMS and ATLAS Collaborations use the reaction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi><mo stretchy="false">→</mo><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></math> in Pb-Pb and proton-proton UPCs to constrain tau’s anomalous magnetic moment <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mi>τ</mi></msub></math>. By parametrizing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>τ</mi><mi>τ</mi></math> vertex with two form factors <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>F</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></math>, the cross section can be written as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>σ</mi><msub><mi>a</mi><mi>τ</mi></msub></msub><mo>=</mo><msub><mi>σ</mi><mi>LO</mi></msub><mo>+</mo><mi>δ</mi><msub><mi>σ</mi><msub><mi>a</mi><mi>τ</mi></msub></msub></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>δ</mi><msub><mi>σ</mi><msub><mi>a</mi><mi>τ</mi></msub></msub></math> is proportional to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mi>τ</mi></msub></math>. The impact of NLO EW corrections on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mi>τ</mi></msub></math> bounds in a Pb-Pb UPC is limited, as the current experimental bounds are loose. We also find that various differential distributions of the two ratios <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">d</mi><msub><mi>σ</mi><mi>NLO</mi></msub><mo>/</mo><mi mathvariant="normal">d</mi><msub><mi>σ</mi><mi>LO</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">d</mi><msub><mi>σ</mi><msub><mi>a</mi><mi>τ</mi></msub></msub><mo>/</mo><mi mathvariant="normal">d</mi><msub><mi>σ</mi><mi>LO</mi></msub></math> have different line shapes. This work is significant to precisely study the interaction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>τ</mi><mi>τ</mi></math> via the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi><mo stretchy="false">→</mo><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></math> process.</p>

Peng-Cheng Lu

Han Zhang

Xin-Yi Zhang

NLO EW corrections to tau pair production via photon fusion in Pb-Pb ultraperipheral collisions

Precise determination of the Higgs boson self-couplings is essential for understanding the mechanism underlying electroweak symmetry breaking. However, owing to the limited number of Higgs boson pair events at the LHC, only loose constraints have been established to date. Current constraints are based on the assumption that the cross section is a quadratic function of the trilinear Higgs self-coupling within the   $\kappa$   framework. Incorporating higher-order quantum corrections from virtual Higgs bosons would significantly alter this functional form, introducing new quartic and cubic power dependencies on the trilinear Higgs self-coupling. To derive this new functional form, we propose a specialized renormalization procedure that tracks all Higgs self-couplings at each calculation step. Additionally, we introduce renormalization constants for coupling modifiers within the   $\kappa$   framework to ensure the cancellation of all ultraviolet divergences. With new functional forms of the cross sections in both the gluon-gluon fusion and vector boson fusion channels, the upper limit of   $\kappa$   set by the ATLAS (CMS) collaboration is reduced from 6.6 (6.49) to 5.4 (5.37). However, extracting a meaningful constraint on the quartic Higgs self-coupling   $\kappa$   from Higgs boson pair production data remains challenging. We also present the invariant mass distributions of the Higgs boson pair at different values of the self-couplings, which could assist in setting optimal cuts for experimental analysis.

Hai Tao Li

Jian Wang

Xiao Zhang

Dan Zhao

Improved constraints on Higgs boson self-couplings with quartic and cubic power dependencies of the cross section  

Treating <math><mi>X</mi><mo>(</mo><mn>4140</mn><mo>)</mo></math> as a compact <math><mrow><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><msup><mrow><mn>1</mn></mrow><mrow><mo>+</mo><mo>+</mo></mrow></msup></mrow></math> <math><mrow><mi>c</mi><mi>s</mi><mover><mrow><mi>c</mi></mrow><mrow><mo>¯</mo></mrow></mover><mover><mrow><mi>s</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math> state and using its mass as a reference scale, we systematically estimate the masses of doubly heavy tetraquark states <math><mi>Q</mi><mi>Q</mi><mover><mi>q</mi><mo>¯</mo></mover><mover><mi>q</mi><mo>¯</mo></mover></math>, where <math><mrow><mi>Q</mi><mo>=</mo><mi>c</mi></mrow></math>, <math><mrow><mi>b</mi></mrow></math> and <math><mi>q</mi><mo>=</mo><mi>u</mi></math>, <math><mrow><mi>d</mi></mrow></math>, <math><mrow><mi>s</mi></mrow></math>. Their decay properties are studied with a simple rearrangement scheme. Based on our results, the lowest <math><mi>I</mi><mo>(</mo><msup><mi>J</mi><mi>P</mi></msup><mo>)</mo><mo>=</mo><mn>0</mn><mo>(</mo><msup><mn>1</mn><mo>+</mo></msup><mo>)</mo></math> <math><mi>b</mi><mi>b</mi><mover><mi>n</mi><mo>¯</mo></mover><mover><mi>n</mi><mo>¯</mo></mover></math> state is a stable tetraquark about 20 MeV below the <math><msup><mover><mi>B</mi><mo>¯</mo></mover><mo>*</mo></msup><mover><mi>B</mi><mo>¯</mo></mover></math> threshold. The mass and width of the low-mass <math><mn>0</mn><mo>(</mo><msup><mn>1</mn><mo>+</mo></msup><mo>)</mo></math> <math><mi>c</mi><mi>c</mi><mover><mi>n</mi><mo>¯</mo></mover><mover><mi>n</mi><mo>¯</mo></mover></math> (<math><mrow><mi>n</mi><mo>=</mo><mi>u</mi></mrow></math>, <math><mrow><mi>d</mi></mrow></math>) tetraquark are compatible with the <math><msub><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub><mo>(</mo><mn>3875</mn><msup><mo>)</mo><mo>+</mo></msup></math> observed by the LHCb Collaboration. The locations of the lowest <math><mn>0</mn><mo>(</mo><msup><mn>0</mn><mo>+</mo></msup><mo>)</mo></math> and <math><mn>0</mn><mo>(</mo><msup><mn>1</mn><mo>+</mo></msup><mo>)</mo></math> <math><mi>b</mi><mi>c</mi><mover><mi>n</mi><mo>¯</mo></mover><mover><mi>n</mi><mo>¯</mo></mover></math> states are found to be close to the <math><mover><mi>B</mi><mo>¯</mo></mover><mi>D</mi></math> and <math><msup><mover><mi>B</mi><mo>¯</mo></mover><mo>*</mo></msup><mi>D</mi></math> thresholds, respectively. We hope that the predicted ratios between partial widths of different channels may be helpful to identify compact tetraquark states from future measurements.

Zi-Long Man

Jing Wu

Doubly heavy tetraquark states in a mass splitting model

We report on the first measurement of the elemental fragmentation cross sections (EFCSs) of <math><mmultiscripts><mrow><mi>Si</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>29</mn><mo>−</mo><mn>33</mn></mrow></mmultiscripts></math> on a carbon target at ∼230 MeV/nucleon. The experimental data covering charge changes of ΔZ = 1-4 are reproduced well by the isospin-dependent quantum molecular dynamics (IQMD) coupled with the evaporation GEMINI (IQMD+GEMINI) model. We further explore the mechanisms underlying the single-proton removal reaction in this model framework. We conclude that the cross sections from direct proton knockout exhibit an overall weak dependence on the mass number of Si projectiles. The proton evaporation induced after the projectile excitation significantly affects the cross sections for neutron-deficient Si isotopes, while neutron evaporation plays a crucial role in the reactions of neutron-rich Si isotopes. It is presented that the relative magnitude of one-proton and one-neutron separation energies is an essential factor that influences evaporation processes. Therefore, proton evaporation should be incorporated into the reaction model in addition to the direct proton knockout in analyses of Gade-Tostevin systematic for single-proton removal reactions.

Guang-Shuai Li

Bao-Hua Sun

Jun Su

Japan

Isao Tanihata

Satoru Terashima

Germany

Jian-Wei Zhao

Er-Xi Xiao

Ji-Chao Zhang

Liu-Chun He

Ge Guo

Wei-Ping Lin

Wen-Jian Lin

Chuan-Ye Liu

Chen-Gui Lu

Bo Mei

Dan-Yang Pang

Ye-Lei Sun

Zhi-Yu Sun

Meng Wang

Feng Wang

Jing Wang

Shi-Tao Wang

Xiu-Lin Wei

Xiao-Dong Xu

Jun-Yao Xu

Li-Hua Zhu

Yong Zheng

Mei-Xue Zhang

Xue-Heng Zhang

Single-proton removal reaction in the IQMD+GEMINI model benchmarked by elemental fragmentation cross sections of Si on carbon at ∼230 MeV/nucleon

The inclusive production of pseudoscalar heavy quarkonia (<math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math>, <math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mi>b</mi></mrow></msub></mrow></math>, and <math><msub><mi>B</mi><mi>c</mi></msub></math>) via photon-photon fusion in heavy ion ultraperipheral collision (UPC) are calculated to QCD next-to-leading order in the framework of nonrelativistic QCD (NRQCD). The total cross section of <math><msub><mi>η</mi><mi>c</mi></msub></math> produced in Pb-Pb UPC is <math><mrow><mn>194</mn><mtext> </mtext><mtext> </mtext><mi>nb</mi></mrow></math> and <math><mrow><mn>1275</mn><mtext> </mtext><mtext> </mtext><mi>nb</mi></mrow></math> at nucleon-nucleon c.m. energies <math><msqrt><msub><mi>S</mi><mi>NN</mi></msub></msqrt><mo>=</mo><mn>5.52</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> and 39.4 TeV, respectively. The cross sections for <math><msub><mi>η</mi><mi>b</mi></msub></math> and <math><msub><mi>B</mi><mi>c</mi></msub></math> mesons are more than two to three orders of magnitude smaller. We make a detailed phenomenological analysis on the <math><msub><mi>η</mi><mi>c</mi></msub></math> production; the uncertainties caused by the renormalization scale and the charm quark mass, the cross sections in other ultraperipheral nucleon-nucleon colliding systems, and the transverse momentum distribution are discussed. At the coming HL-LHC and future FCC, the heavy ion UPC opens another door of the study on the production of heavy quarkonium.

Cong-Feng Qiao

Hao Yang

Pseudoscalar heavy quarkonium production in heavy ion ultraperipheral collision

We consider top-antitop quark <math><mo>(</mo><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover><mo>)</mo></math> production at the Large Hadron Collider (LHC) with subsequent decays into dileptonic final states. We use and investigate a set of leptonic angular correlations and distributions with which all the independent coefficient functions of the top-spin-dependent parts of the <math><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></math> production spin density matrices can be experimentally probed. We compute these observables for the LHC center-of-mass energy 13.6 TeV within the Standard Model at next-to-leading order in the QCD coupling including the mixed QCD weak corrections. We determine also the <math><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></math> charge asymmetry where we take in addition also the mixed QCD-QED corrections into account. In addition we analyze and compute possible new physics (NP) effects on these observables within effective field theory in terms of a gauge-invariant effective Lagrangian that contains the operators up to mass dimension six that are relevant for hadronic <math><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></math> production. First, we compute our observables inclusive in phase space. Then, in order to investigate which region in phase space has, for a specific observable, a high NP sensitivity, we determine our observables also in two-dimensional <math><mo>(</mo><msub><mi>M</mi><mrow><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></mrow></msub><mo>,</mo><mi>cos</mi><msubsup><mi>θ</mi><mi>t</mi><mo>*</mo></msubsup><mo>)</mo></math> bins, where <math><msub><mi>M</mi><mrow><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></mrow></msub></math> denotes the <math><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></math>-invariant mass and <math><msubsup><mi>θ</mi><mi>t</mi><mo>*</mo></msubsup></math> is the top quark scattering angle in the <math><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></math> zero-momentum frame.

Werner Bernreuther

Long Chen

Binned top quark spin correlation and polarization observables for the LHC at 13.6 TeV

We studied the spectrum and rearrangement decays of S-wave   $ cs\bar{c}\bar{s} $   tetraquark states in a simplified quark model. The masses and widths were estimated by assuming that   $ cs\bar{c}\bar{s} $   is the lower   $ cs\bar{c}\bar{s} $   tetraquark. Comparing our results with experimental measurements, we found that   $ cs\bar{c}\bar{s} $  , recently observed by LHCb, can be considered the lowest   $ cs\bar{c}\bar{s} $   tetraquark state and   $ cs\bar{c}\bar{s} $   could be the second lowest   $ cs\bar{c}\bar{s} $   tetraquark. Predictions of ratios between partial widths for the involved tetraquarks are provided in this paper. We aim to identify more   $ cs\bar{c}\bar{s} $   tetraquarks with   $ cs\bar{c}\bar{s} $  ,   $ cs\bar{c}\bar{s} $  , and   $ cs\bar{c}\bar{s} $  .

 (3960),  (4140), and Other Compact States  

The finite mass of the heavy quark suppresses the collimated radiations; this is generally referred to as the dead cone effect. In this paper, we study the distribution of hadron multiplicity over the hadron opening angle with respect to the jet axis for various jet flavors. The corresponding measurement can be the most straightforward and simplest approach to explore the dynamical evolution of the radiations in the corresponding jet, which can expose the mass effect. We also propose a transverse energy-weighted angular distribution, which sheds light on the interplay between perturbative and non-perturbative effects in the radiation. Through Monte-Carlo simulations, our calculations show that the dead cone effect can be clearly observed by finding the ratio between the b and light-quark (inclusive) jets; this is expected to be measured at the LHC in the future.

Chuan-Hui Jiang

Mass suppression effect in QCD radiation and hadron angular distribution in jet  

The spin-orbit splitting between neutron 1p orbitals at $^{33}$Si has been deduced using the single-neutron-adding (d,p) reaction in inverse kinematics with a beam of $^{32}$Si, a long-lived radioisotope. Reaction products were analyzed by the newly implemented SOLARIS spectrometer at the reaccelerated-beam facility at the National Superconducting Cyclotron Laboratory. The measurements show reasonable agreement with shell-model calculations that incorporate modern cross-shell interactions, but they contradict the prediction of proton density depletion based on relativistic mean-field theory. The evolution of the neutron 1p-shell orbitals is systematically studied using the present and existing data in the isotonic chains of <math><mi>N</mi><mo>=</mo><mn>17</mn></math>, 19, and 21. In each case, a smooth decrease in the separation of the <math><mn>1</mn><msub><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub></math>-<math><mn>1</mn><msub><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math> orbitals is seen as the respective p-orbitals approach zero binding, suggesting that the finite nuclear potential strongly influences the evolution of nuclear structure in this region.

United States

J. Chen

B.P. Kay

C.R. Hoffman

T.L. Tang

I.A. Tolstukhin

D. Bazin

R.S. Lubna

Spain

Y. Ayyad

S. Beceiro-Novo

Australia

B.J. Coombes

United Kingdom

CERN

S.J. Freeman

L.P. Gaffney

R. Garg

H. Jayatissa

A.N. Kuchera

P. MacGregor

A.J. Mitchell

W. Mittig

B. Monteagudo

A. Munoz-Ramos

C. Müller-Gatermann

Italy

F. Recchia

N. Rijal

C. Santamaria

M.Z. Serikow

D.K. Sharp

J. Smith

J.K. Stecenko

G.L. Wilson

A.H. Wuosmaa

C.X. Yuan

J.C. Zamora

Y.N. Zhang

Evolution of the nuclear spin-orbit splitting explored via the Si( , ) Si reaction using SOLARIS