Chinese Physics C

A discussion on the anomalous threshold enhancement of $ {\boldsymbol J/\boldsymbol\psi }$ –${ \boldsymbol\psi \bf (3770) }$ couplings and ${\boldsymbol X \bf (6900) }$ peak

Ye Lu, Chang Chen, Guang-You Qin, Han-Qing Zheng

2024, 48(4): 041001. doi: 10.1088/1674-1137/ad2361

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Abstract:
The attractive interaction between

\begin{document}$ J/\psi $\end{document}

and

\begin{document}$ \psi(3770) $\end{document}

has to be strong enough if X(6900) is of the molecule type. We argue that since

\begin{document}$ \psi(3770) $\end{document}

decays predominantly into a

\begin{document}$ D\bar D $\end{document}

pair, the interactions between

\begin{document}$ J/\psi $\end{document}

and

\begin{document}$ \psi(3770) $\end{document}

may be significantly enhanced owing to the three point

\begin{document}$ D\bar D $\end{document}

loop diagram. The enhancement originates from the anomalous threshold located at

\begin{document}$ t=-1.288 $\end{document}

GeV

\begin{document}$ ^2 $\end{document}

, whose effect propagates into the s-channel partial wave amplitude in the vicinity of

\begin{document}$ \sqrt{s}\simeq 6.94 $\end{document}

GeV. This effect may be helpful in the formation of the

\begin{document}$ X(6900) $\end{document}

peak.

Search for production of dark fermion candidates in association with heavy neutral gauge boson decaying to dimuon in proton-proton collisions at${ \sqrt{\boldsymbol s} \bf = 8} $ TeV using CMS open data

Y. Mahmoud, H. Abdallah, M. T. Hussein, S. Elgammal

2024, 48(4): 043001. doi: 10.1088/1674-1137/ad20d5

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Abstract:
In this study, we conducted a search for dark matter using a part of the data recorded by the CMS experiment during run-I of the LHC in 2012 with a center of mass energy of 8 TeV and an integrated luminosity of 11.6 fb⁻¹. These data were gathered from the CMS open data. Dark matter, in the framework of the simplified model (mono-Z

\begin{document}$ ^{\prime} $\end{document}

), can be produced from proton-proton collisions in association with a new hypothetical gauge boson, Z

\begin{document}$ ^{\prime} $\end{document}

. Thus, the search was conducted in the dimuon plus large missing transverse momentum channel. One benchmark scenario of mono-Z

\begin{document}$ ^{\prime} $\end{document}

, which is known as light vector, was used for interpreting the CMS open data. No evidence of dark matter was observed, and exclusion limits were set on the masses of dark matter and Z

\begin{document}$ ^{\prime} $\end{document}

at 95% confidence level.

${\mathrm{SANC}}$ Monte Carlo programs for small-angle Bhabha scattering

A.B. Arbuzov, S.G. Bondarenko, I.R. Boyko, L.V. Kalinovskaya, A.A. Kampf, R.R. Sadykov, V.L. Yermolchyk

2024, 48(4): 043002. doi: 10.1088/1674-1137/ad1fe6

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Luminosity monitoring at

\begin{document}$ e^+e^- $\end{document}

colliders was investigated using

\begin{document}$\mathrm{SANC}$\end{document}

Monte Carlo event generator

\begin{document}$\mathrm{ReneSANCe}$\end{document}

and integrator

\begin{document}$\mathrm{MCSANC}$\end{document}

for simulation of Bhabha scattering at low angles. Results are presented for center-of-mass energies of the Z boson resonance and at 240 GeV for the conditions of typical luminosity detectors. It is shown that bremsstrahlung events with extremely low electron scattering angles are relevant to match the precision tags of future electron-positron colliders.

Solar neutrino background in high-pressure gaseous ⁸²SeF₆ TPC neutrinoless double beta decay experiments

Jiemiao Wang, Hulin Wang, Dongliang Zhang

2024, 48(4): 043003. doi: 10.1088/1674-1137/ad2675

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Abstract:
In this study, the possibility of observing a solar neutrino background in a future neutrinoless double beta decay experiment using a high-pressure gaseous ⁸²SeF₆ TPC is investigated. Various contributions are simulated, and possible features that could be used for event classification are discussed; two types of backgrounds are identified. The rate of multi-site background events is approximately 0.63 events/(ton·yr) in a 30 keV ROI window. This background could be effectively reduced to less than 0.0001 events/(ton·yr) (95% C.L.) while maintaining a high signal efficiency of 93% by applying a selection based on the number of clusters and energy of the leading cluster. The rate of the single-electron background events is approximately 0.01 events/(ton·yr) in the ROI. Assuming a reduction factor of 10 for the single-electron background events obtained via the algorithms developed for radioactive background rejection, the total background induced by the solar neutrino would be 0.001 events/(ton·yr), which is sufficiently small for conducting ton-level experiments.

Leptonic di-flavor and di-number violation processes at high energy ${{ {\boldsymbol\mu}^{\bf\pm}}{\boldsymbol\mu}^{\bf\pm}} $ colliders

Jin-Lei Yang, Chao-Hsi Chang, Tai-Fu Feng

2024, 48(4): 043101. doi: 10.1088/1674-1137/ad17b0

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The leptonic di-flavor violation (LFV) processes

\begin{document}$ \mu^\pm \mu^\pm \rightarrow e^\pm e^\pm $\end{document}

and

\begin{document}$ \mu^\pm \mu^\pm \rightarrow \tau^\pm \tau^\pm $\end{document}

and leptonic di-number violation (LNV) processes

\begin{document}$ \mu^\pm \mu^\pm \rightarrow W^\pm _iW^\pm _j $\end{document}

(

\begin{document}$ i,\;j=1,\;2 $\end{document}

) at same-sign high energy

\begin{document}$ \mu^\pm \mu^\pm $\end{document}

colliders are studied. The new physics (NP) factors that may play roles in these processes are highlighted by cataloging them into three types. Taking into account the experimental constraints, the processes at

\begin{document}$ \mu^\pm\mu^\pm $\end{document}

colliders are computed, and the results are presented properly. The results lead to the conclusion that observing the NP factors through the LFV and LNV processes at TeV-energy

\begin{document}$ \mu^\pm\mu^\pm $\end{document}

colliders has significant advantages that cannot be achieved elsewhere. Therefore, once the techniques for muon acceleration and collision are developed successfully, the option of building same-sign high energy muon colliders should be seriously considered.

Some remarks on compositeness of ${{\boldsymbol T}^{\bf +}_{\boldsymbol{cc}}} $

Chang Chen, Ce Meng, Zhiguang Xiao, Han-Qing Zheng

2024, 48(4): 043102. doi: 10.1088/1674-1137/ad1a0b

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Recently, the LHCb experimental group found an exotic state

\begin{document}$ T^+_{cc} $\end{document}

from the

\begin{document}$ pp \to D^0D^0\pi^+ + X $\end{document}

process. A key question is whether it is just a molecule or may have a confined tetraquark ingredient. To investigate this, different methods were used, including a two-channel (

\begin{document}$ D^{*+}D^0 $\end{document}

and

\begin{document}$ D^{*0}D^+ $\end{document}

) K-matrix unitarization and a single-channel Flatté-like parametrization method analyzed utilizing the pole counting rule and spectral density function sum rule. These analyses demonstrated that

\begin{document}$ T^+_{cc} $\end{document}

is a molecular state, although the possibility that there may exist an elementary ingredient cannot be excluded, according to an approximate analysis of its production rate.

Searching for the light leptophilic gauge boson Z_xvia four-lepton final states at the CEPC

Chong-Xing Yue, Yan-Yu Li, Mei-Shu-Yu Wang, Xin-Meng Zhang

2024, 48(4): 043103. doi: 10.1088/1674-1137/ad25f5

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We investigate the possibility of detecting the leptophilic gauge boson

\begin{document}$ Z_x $\end{document}

predicted by the

\begin{document}$ U(1)_{L_e-L_\mu} $\end{document}

model via the processes

\begin{document}$ e^+e^-\rightarrow \ell^+\ell^-Z_x(Z_x\rightarrow \ell^+\ell^-) $\end{document}

and

\begin{document}$ e^+e^-\rightarrow \ell^+\ell^-Z_x(Z_x\rightarrow \nu_\ell\bar{\nu_\ell}) $\end{document}

at the Circular Electron Positron Collider (CEPC) with a center of mass energy

\begin{document}$ \sqrt s=240 $\end{document}

GeV and luminosity

\begin{document}$ \mathcal{L}=5.6 \;\; \mathrm{ab^{-1}} $\end{document}

. We provide the expected sensitivities of the CEPC to the parameter space at the

\begin{document}$ 1\sigma $\end{document}

,

\begin{document}$ 2\sigma $\end{document}

,

\begin{document}$ 3\sigma $\end{document}

, and

\begin{document}$ 5\sigma $\end{document}

levels.

Higgs-like (pseudo)scalars in AdS₄, marginal and irrelevant deformations in CFT₃, and instantons on S³

M. Naghdi

2024, 48(4): 043104. doi: 10.1088/1674-1137/ad205f

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Employing a 4-form ansatz of 11-dimensional supergravity over a non-dynamical

\begin{document}$AdS_4 \times S^7/Z_k$\end{document}

background and setting the internal space as an

\begin{document}$S^1$\end{document}

Hopf fibration on

\begin{document}$CP^3$\end{document}

, we obtain a consistent truncation. The (pseudo)scalars, in the resulting scalar equations in Euclidean AdS

\begin{document}$_4$\end{document}

space, may be considered to arise from (anti)M-branes wrapping around the internal directions in the (Wick-rotated) skew-whiffed M2-brane background (as the resulting theory is for anti-M2-branes), thus realizing the modes after swapping the three fundamental representations

\begin{document}${\bf{8}}_s$\end{document}

,

\begin{document}${\bf{8}}_c$\end{document}

, and

\begin{document}${\bf{8}}_v$\end{document}

of

\begin{document}$S O(8)$\end{document}

. Taking the backreaction on the external and internal spaces, we obtain the massless and massive modes, corresponding to exactly marginal and marginally irrelevant deformations on the boundary CFT

\begin{document}$_3$\end{document}

, respectively. Subsequently, we obtain a closed solution for the bulk equation and compute its correction with respect to the background action. Next, considering the Higgs-like (breathing) mode

\begin{document}$m^2=18$\end{document}

, having all supersymmetries as well as parity and scale-invariance broken, solving the associated bulk equation with mathematical methods, specifically the Adomian decomposition method, and analyzing the behavior near the boundary of the solutions, we realize the boundary duals in the

\begin{document}$S U(4) \times U(1)$\end{document}

-singlet sectors of the ABJM model. Then, introducing the new dual deformation

\begin{document}$\Delta_+ = 3, 6$\end{document}

operators made of bi-fundamental scalars, fermions, and

\begin{document}$U(1)$\end{document}

gauge fields, we obtain the

\begin{document}$S O(4)$\end{document}

-invariant solutions as small instantons on a three-sphere with the radius at infinity, which correspond to collapsing bulk bubbles leading to big-crunch singularities.

Revisiting the top-quark pair production at future e⁺e⁻ colliders

Jin Ma, Sheng-Quan Wang, Ting Sun, Jian-Ming Shen, Xing-Gang Wu

2024, 48(4): 043105. doi: 10.1088/1674-1137/ad243e

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In this study, we reanalyze the top-quark pair production at next-to-next-to-leading order (NNLO) in quantum chromodynamics (QCD) at future

\begin{document}$ e^+e^- $\end{document}

colliders using the Principle of Maximum Conformality (PMC) method. The PMC renormalization scales in

\begin{document}$ \alpha_s $\end{document}

are determined by absorbing the non-conformal β terms by recursively using the Renormalization Group Equation (RGE). Unlike the conventional scale-setting method of fixing the scale at the center-of-mass energy

\begin{document}$ \mu_r=\sqrt{s} $\end{document}

, the determined PMC scale

\begin{document}$ Q_\star $\end{document}

is far smaller than the

\begin{document}$ \sqrt{s} $\end{document}

and increases with the

\begin{document}$ \sqrt{s} $\end{document}

, yielding the correct physical behavior for the top-quark pair production process. Moreover, the convergence of the pQCD series for the top-quark pair production is greatly improved owing to the elimination of the renormalon divergence. For a typical collision energy of

\begin{document}$ \sqrt{s}=500 $\end{document}

GeV, the PMC scale is

\begin{document}$ Q_\star=107 $\end{document}

GeV; the QCD correction factor K for conventional results is

\begin{document}$ K\sim1+0.1244^{+0.0102+0.0012}_{-0.0087-0.0011}+0.0184^{-0.0086+0.0002}_{+0.0061-0.0003} $\end{document}

, where the first error is caused by varying the scale

\begin{document}$ \mu_r\in[\sqrt{s}/2, 2\sqrt{s}] $\end{document}

and the second error is from the top-quark mass

\begin{document}$ \Delta{m_t}=\pm0.7 $\end{document}

GeV. After applying the PMC, the renormalization scale uncertainty is eliminated, and the QCD correction factor K is improved to

\begin{document}$ K\sim 1+0.1507^{+0.0015}_{-0.0015}-0.0057^{+0.0001}_{-0.0000} $\end{document}

, where the error is from the top-quark mass

\begin{document}$ \Delta{m_t}=\pm0.7 $\end{document}

GeV. The PMC improved predictions for the top-quark pair production are helpful for detailed studies of the properties of the top-quark at future

\begin{document}$ e^+e^- $\end{document}

colliders.

Correlations of baryon and charge stopping in heavy ion collisions

Wendi Lv, Yang Li, Ziyang Li, Rongrong Ma, Zebo Tang, Prithwish Tribedy, Chun Yuen Tsang, Zhangbu Xu, Wangmei Zha

2024, 48(4): 044001. doi: 10.1088/1674-1137/ad243f

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Baryon numbers are theorized to be carried by valence quarks in the standard QCD picture of the baryon structure. Another theory proposed an alternative baryon number carrier, a non-perturbative Y-shaped configuration of the gluon field, called the baryon junction in the 1970s. However, neither of these theories has been verified experimentally. Recently, searching for the baryon junction by investigating the correlation of net-charge and net-baryon yields at midrapidity in heavy-ion collisions has been suggested. This paper presents studies of such correlations in collisions of various heavy ions from oxygen to uranium with the UrQMD Monte Carlo model. The UrQMD model implements valence quark transport as the primary means of charge and baryon stopping at midrapidity. Detailed studies are also conducted for isobaric

\begin{document}$ _{40}^{96}{\rm{Zr}} $\end{document}

+

\begin{document}$ _{40}^{96}{\rm{Zr}} $\end{document}

and

\begin{document}$ _{44}^{96}{\rm{Ru}} $\end{document}

+

\begin{document}$ _{44}^{96}{\rm{Ru}} $\end{document}

collisions. We found a universal trend of charge stopping with respect to baryon stopping and discovered that the charge stopping is always greater than the baryon stopping. This study provides a model baseline in valence quark transport for what is expected in net-charge and net-baryon yields at the midrapidity of relativistic heavy-ion collisions.

Tensor force impact on shell evolution in neutron-rich Si and Ni isotopes

S.V. Sidorov, A.S. Kornilova, T.Yu. Tretyakova

2024, 48(4): 044101. doi: 10.1088/1674-1137/ad20d4

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The influence of the tensor interaction of nucleons on the characteristics of neutron-rich silicon and nickel isotopes was studied in this work. Tensor forces are considered within the framework of the Hartree-Fock approach with the Skyrme interaction. The addition of a tensor component of interaction is shown to improve the description of the splittings between different single-particle states and decrease nucleon-nucleon pairing correlations in silicon and nickel nuclei. Special attention was directed toward the role of isovector tensor forces relevant to the interaction of like nucleons.

Theoretical calculations of proton emission half-lives based on a deformed Gamow-like model

Dong-Meng Zhang, Xiao-Yuan Hu, Lin-Jing Qi, Hong-Ming Liu, Ming Li, Xiao-Hua Li

2024, 48(4): 044102. doi: 10.1088/1674-1137/ad243d

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In this study, proton emission half-lives were investigated for deformed proton emitters with

\begin{document}$ 53\leq Z \leq 83 $\end{document}

based on the presented deformed Gamow-like model, where the deformation effect was included in the Coulomb potential. The experimental half-lives of proton emitters can be reproduced within a factor of 3.45. For comparison, the results from the universal decay law and the new Geiger-Nuttall law are also presented. Furthermore, the relevance of the half-lives to the angular momentum l for ¹¹⁷La, ¹²¹Pr, ¹³⁵Tb, and ¹⁴¹Ho were analyzed, and the corresponding possible values of l were proposed: l = 3, 3, 4, 4.

Exploration of the ground state properties of neutron-rich sodium isotopes using the deformed relativistic mean field theory in complex momentumrepresentations with BCS pairings

Yu-Xuan Luo, Quan Liu, Jian-You Guo

2024, 48(4): 044103. doi: 10.1088/1674-1137/ad1fe3

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This study explores the ground-state characteristics of neutron-rich sodium isotopes, encompassing two-neutron separation energies, root-mean-square radii, quadrupole moments of proton and neutron distributions, single-particle levels of bound and resonant states, and neutron density distributions and shapes. Simultaneously, special attention is paid to the distinctive physical phenomena associated with these isotopes. The deformed relativistic mean field theory in complex momentum representations with BCS pairings (DRMF-CMR-BCS) employed in our research provides resonant states with real physics, offering insights into deformed halo nuclei. Four effective interactions (NL3, NL3^*, PK1, and NLSH) were considered to assess the influence of continuum and deformation effects on halo structures. Calculations for odd-even nuclei ^35–43Na revealed the dependence on the chosen effective interaction and number of considered resonant states. Neutron occupation patterns near the Fermi surface, particularly in orbitals

\begin{document}$ 1/2^{-}_3 $\end{document}

and

\begin{document}$ 3/2^{-}_2 $\end{document}

, were determined to be crucial in halo formation. The study provided detailed insights into the density distributions, shape evolution, and structure of neutron-rich sodium isotopes, contributing valuably to the field of nuclear physics.

Astrophysical S-factor and reaction rate for ¹⁵N(p,γ)¹⁶O within the modified potential cluster model

S. B. Dubovichenko, A. S. Tkachenko, R. Ya. Kezerashvili, N. A. Burkova, B. M. Yeleusheva

2024, 48(4): 044104. doi: 10.1088/1674-1137/ad1fe7

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We study radiative

\begin{document}$ p^{15} {\rm{N}}$\end{document}

capture on the ground state of ¹⁶O at stellar energies within the framework of a modified potential cluster model (MPCM) with forbidden states, including low-lying resonances. The investigation of the ¹⁵N(

\begin{document}$ p, \gamma _{0} $\end{document}

)¹⁶O reaction includes the consideration of

\begin{document}$ {}^{3}S_{1} $\end{document}

resonances due to

\begin{document}$ E1 $\end{document}

transitions and the contribution of the

\begin{document}$ {}^{3}P_{1} $\end{document}

scattering wave in the p + ¹⁵N channel due to the

\begin{document}$ {}^{3}P_{1}\longrightarrow $\end{document}

\begin{document}$ {}^{3}P_{0} $\end{document}

\begin{document}$ M1 $\end{document}

transition. We calculated the astrophysical low-energy S-factor, and the extrapolated

\begin{document}$ S(0) $\end{document}

turned out to be within 34.7−40.4 keV·b. The important role of the asymptotic constant (AC) for the ¹⁵N(

\begin{document}$ p, \gamma _{0} $\end{document}

)¹⁶O process with interfering

\begin{document}$ {}^{3}S_{1} $\end{document}

(312) and

\begin{document}$ {}^{3}S_{1} $\end{document}

(962) resonances is elucidated. A comparison of our calculation for the S-factor with existing experimental and theoretical data is addressed, and a reasonable agreement is found. The reaction rate is calculated and compared with the existing rates. It has negligible dependence on the variation of AC but shows a strong impact of the interference of

\begin{document}$ {}^{3}S_{1} $\end{document}

(312) and

\begin{document}$ {}^{3}S_{1} $\end{document}

(962) resonances in reference to the CNO Gamow windows, especially at low temperatures. We estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from Phys. Rev. C. 85, 065810 (2012). The reaction rate enhancement due to the cascade transitions is observed from

\begin{document}$ T_{9} > 0.3 $\end{document}

and reaches the maximum factor ~ 1.3 at

\begin{document}$ T_{9}=1.3 $\end{document}

. We present the Gamow energy window and a comparison of rates for radiative proton capture reactions ¹²N(

\begin{document}$ p, \gamma $\end{document}

)¹³O, ¹³N(

\begin{document}$ p, \gamma $\end{document}

) ¹⁴O, ¹⁴N(

\begin{document}$ p, \gamma $\end{document}

)¹⁵O, and ¹⁵N(

\begin{document}$ p, \gamma $\end{document}

)¹⁶O obtained in the framework of the MPCM and provide the temperature windows, prevalence, and significance of each process.

α-particle preformation factors in heavy and superheavy nuclei

Song Luo, Dong-Meng Zhang, Lin-Jing Qi, Xun Chen, Peng-Cheng Chu, Xiao-Hua Li

2024, 48(4): 044105. doi: 10.1088/1674-1137/ad21e9

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In this study, α-particle preformation factors in heavy and superheavy nuclei from ²²⁰Th to ²⁹⁴Og are investigated. By combing experimental α decay energies and half-lives, the α-particle preformation factors

\begin{document}$ P_{\alpha} $\end{document}

are extracted from the ratios between theoretical α decay half-lives calculated using the Two-Potential Approach (TPA) and experimental data. We find that the α-particle preformation factors exhibit a noticeable odd-even staggering behavior, and unpaired nucleons inhibit α-particle preformation. Moreover, we find that both the α decay energy and mass number of parent nucleus exhibit considerable regularity with the extracted experimental α-particle preformation factors. After considering the major physical factors, we propose a local phenomenological formula with only five valid parameters for α-particle preformation factors

\begin{document}$ P_{\alpha} $\end{document}

. This analytic expression has a clear physical meaning as well as good precision. As an application, this analytic formula is extended to estimate the α-particle preformation factors and further predict the α decay half-lives for unknown even-even nuclei with Z = 118 and 120.

Simulating gamma-ray production from cosmic rays interacting with the solar atmosphere in the presence of coronal magnetic fields

Zhe Li, Kenny C. Y. Ng, Songzhan Chen, Yuncheng Nan, Huihai He

2024, 48(4): 045101. doi: 10.1088/1674-1137/ad1cda

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Cosmic rays can interact with the solar atmosphere and produce a slew of secondary messengers, making the Sun a bright gamma-ray source in the sky. Detailed observations with Fermi-LAT have shown that these interactions must be strongly affected by solar magnetic fields in order to produce a wide range of observational features, such as a high flux and hard spectrum. However, the detailed mechanisms behind these features are still a mystery. In this study, we tackle this problem by performing particle-interaction simulations in the solar atmosphere in the presence of coronal magnetic fields using the potential field source surface (PFSS) model. We find that low-energy (~ GeV) gamma-ray production is significantly enhanced by the coronal magnetic fields, but the enhancement decreases rapidly with energy. The enhancement directly correlates with the production of gamma rays with large deviation angles relative to the input cosmic-ray direction. We conclude that coronal magnetic fields are essential for correctly modeling solar disk gamma rays below 10 GeV, but above that, the effect of coronal magnetic fields diminishes. Other magnetic field structures are needed to explain the high-energy disk emission.

Rastall gravity: accretion disk image in the context of radiation fields and visual transformations compared to Reissner-Nordström black hole

Yu-Xiang Huang, Sen Guo, Yu Liang, Yu-Hao Cui, Qing-Quan Jiang, Kai Lin

2024, 48(4): 045102. doi: 10.1088/1674-1137/ad1feb

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In this study, we investigated the astronomical implications of Rastall gravity, particularly its behavior amidst a radiation field compared to Reissner-Nordström (RN) black holes. We found a crucial correlation between the dynamics of the accretion disk and the parameters Q and

\begin{document}$ N_{\rm{r}} $\end{document}

, which properly reflect the influence of spacetime metrics on the disk’s appearance. Elevated electric charge Q causes contraction in the disk’s orbit due to enhanced gravitational effects, while higher

\begin{document}$ N_{\rm{r}} $\end{document}

values lead to outward expansion, influenced by the attributes of the radiation field. Interestingly, the charged black holes surrounded by radiation fields exhibit distinct visual disparities from RN black holes. Brightness decreases and expansion occurs within the innermost stable circular orbit of the accretion disk with rising

\begin{document}$ N_{\rm{r}} $\end{document}

values. Our study also reveals the process by which the accretion disk transitions from a conventional disk-like structure to a hat-like form at different observation angles, with the redshift effect gradually intensifying. Moreover, the results of the considered Rastall gravity radiation field are consistent with the constraints of the gravitational lensing of the host galaxy on Rastall gravity parameters, thereby enhancing the consistency between theoretical predictions and actual observations.

Radiative capture of proton through the ¹⁴N(p,γ)¹⁵O reaction at low energy

B.F. Irgaziev, Abdul Kabir, Jameel-Un Nabi

2024, 48(4): 045103. doi: 10.1088/1674-1137/ad1b3c

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The CNO cycle is the main source of energy in stars more massive than our Sun. This process defines the energy production, the duration of which can be used to determine the lifetime of massive stars. The cycle is an important tool for determining the age of globular clusters. Radiative proton capture via

\begin{document}$ p + {^{14}\rm{N}}\rightarrow {^{15}\rm{O}+{\gamma}} $\end{document}

, at energies of astrophysical interest, is an important process in the CNO cycle. In this project, we apply a potential model to describe both non-resonant and resonant reactions in the channels where radiative capture occurs through electric

\begin{document}$ E1 $\end{document}

transitions. We employed the R-matrix method to describe the ongoing reactions via

\begin{document}$ M1 $\end{document}

resonant transitions, when it was not possible to correctly reproduce the experimental data using the potential model. The partial components of the astrophysical S-factor are calculated for all possible electric and magnetic dipole transitions in ¹⁵O. The linear extrapolated S-factor at zero energy (S(0)) agrees well with earlier reported values for all transition types considered in this work. Based on the value of the total astrophysical S-factor, depending on the collision energy, we calculate the nuclear reaction rates for

\begin{document}$ p + {^{14}\rm{N}}\rightarrow {^{15}\rm{O}+{\gamma}} $\end{document}

. The computed rates agree well with the results reported in the NACRE II Collaboration and most recent existing measurements.

Higgs inflation model with non-minimal coupling in hybrid Palatini approach

Brahim Asfour, Aatifa Bargach, Ahmed Errahmani, Taoufik Ouali

2024, 48(4): 045104. doi: 10.1088/1674-1137/ad1dcd

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In this paper, we propose a hybrid metric Palatini approach in which the Palatini scalar curvature is non minimally coupled to the scalar field. We derive Einstein's field equations, i.e., the equations of motion of the scalar field. Furthermore, the background and perturbative parameters are obtained by means of Friedmann equations in the slow roll regime. The analysis of cosmological perturbations allowed us to obtain the main inflationary parameters, e.g., the scalar spectral index

\begin{document}$ n_s $\end{document}

and tensor to scalar ratio r. From this perspective, as an application of our analysis, we consider the Higgs field with quartic potential, which plays the inflaton role, and show that predictions of Higgs hybrid inflation are in good agreement with recent observational data [Astron. Astrophys. 641, 61 (2020)].

Reconstruction of aether scalar tensor theory for variouscosmological scenarios

Qi-Ming Fu, Meng-Ci He, Tao-Tao Sui, Xin Zhang

2024, 48(4): 045105. doi: 10.1088/1674-1137/ad2360

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In this paper, we present several explicit reconstructions for the aether scalar tensor (AeST) theory derived from the background of the Friedmann-Lemaître-Robertson-Walker cosmological evolution. It is shown that the Einstein-Hilbert Lagrangian with a positive cosmological constant is the only Lagrangian capable of accurately replicating the exact expansion history of the Λ cold dark matter (ΛCDM) universe filled solely with dust-like matter. However, the ΛCDM-era can be produced within the framework of the AeST theory for some other fluids, including a perfect fluid with

\begin{document}$ p=-(1/3)\rho $\end{document}

, multifluids, and nonisentropic perfect fluids. Moreover, we demonstrate that the ΛCDM-era can be replicated with no real matter field for the AeST theory. The cosmic evolution resulting from both the power-law and de-Sitter solutions can also be obtained.

Gravitational wave footprints from Higgs-portal scalegenesis with multiple dark chiral scalars

He-Xu Zhang, Shinya Matsuzaki, Hiroyuki Ishida

2024, 48(4): 045106. doi: 10.1088/1674-1137/ad2b4f

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Abstract:
We discuss the gravitational wave (GW) spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors, which many flavor QCD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry breaking. We employ the linear-sigma model as the low-energy description of dark many flavor QCD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the (approximately realized) flat direction based on the Gildener-Weinberg mechanism. Passing through evaluation of the bubble nucleation/percolation, we address the reheating and relaxation processes, which are generically non-thermal and nonadiabatic. Parametrizing the reheating epoch in terms of the e-folding number, we propose proper formulae for the redshift effects on the GW frequencies and signal spectra. It then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz, unless the released latent heat is transported into another sector other than reheating the universe. Instead, models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity, like at LISA, BBO, and DECIGO, etc. We also find that with large flavors in the dark sector, the GW signals are made further smaller and the peak frequencies higher. Characteristic phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale, which is also briefly addressed.

Analytical solutions of equatorial geodesic motion in Kerr spacetime

Yan Liu, Bing Sun

2024, 48(4): 045107. doi: 10.1088/1674-1137/ad260a

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Abstract:
The study of Kerr geodesics has a long history, particularly for those occurring within the equatorial plane, which are generally well-understood. However, when compared with the classification introduced by one of the authors [Phys. Rev. D 105, 024075 (2022)], it becomes apparent that certain classes of geodesics, such as trapped orbits, still lack analytical solutions. Thus, in this study, we provide explicit analytical solutions for equatorial timelike geodesics in Kerr spacetime, including solutions of trapped orbits, which capture the characteristics of special geodesics, such as the positions and conserved quantities of circular, bound, and deflecting orbits. Specifically, we determine the precise location at which retrograde orbits undergo a transition from counter-rotating to prograde motion due to the strong gravitational effects near a rotating black hole. Interestingly, the trajectory remains prograde for orbits with negative energy despite the negative angular momentum. Furthermore, we investigate the intriguing phenomenon of deflecting orbits exhibiting an increased number of revolutions around the black hole as the turning point approaches the turning point of the trapped orbit. Additionally, we find that only prograde marginal deflecting geodesics are capable of traversing through the ergoregion. In summary, our findings present explicit solutions for equatorial timelike geodesics and offer insights into the dynamics of particle motion in the vicinity of a rotating black hole.

Efficient parameter inference for gravitational wave signals in the presence of transient noises using temporal and time-spectral fusion normalizing flow

Tian-Yang Sun, Chun-Yu Xiong, Shang-Jie Jin, Yu-Xin Wang, Jing-Fei Zhang, Xin Zhang

2024, 48(4): 045108. doi: 10.1088/1674-1137/ad2a5f

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Abstract:
Glitches represent a category of non-Gaussian and transient noise that frequently intersects with gravitational wave (GW) signals, thereby exerting a notable impact on the processing of GW data. The inference of GW parameters, crucial for GW astronomy research, is particularly susceptible to such interference. In this study, we pioneer the utilization of a temporal and time-spectral fusion normalizing flow for likelihood-free inference of GW parameters, seamlessly integrating the high temporal resolution of the time domain with the frequency separation characteristics of both time and frequency domains. Remarkably, our findings indicate that the accuracy of this inference method is comparable to that of traditional non-glitch sampling techniques. Furthermore, our approach exhibits a greater efficiency, boasting processing times on the order of milliseconds. In conclusion, the application of a normalizing flow emerges as pivotal in handling GW signals affected by transient noises, offering a promising avenue for enhancing the field of GW astronomy research.

2024 Vol. 48, No. 4