Chinese Physics C

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Constraints on the canonical single-field slow-roll inflation model from observations

Jun Li, Guanghai Guo, Pengfei Yan, Xiong Yang

Published: , doi: 10.1088/1674-1137/ae8cf2

Abstract:
In this work, we employ two complementary approaches to constrain the canonical single-field slow-roll inflation scenario. The first method makes explicit use of the analytic dependence of the primordial perturbations on the slow-roll parameters, whereas the second adopts a phenomenological parameterization of the primordial scalar and tensor spectra. Using the latest observational datasets, including Planck satellite data, BICEP/Keck measurements, baryon acoustic oscillation data, and the recent DESI Data Release 2, we derive direct constraints on the slow-roll parameters. A key advantage of this strategy is that it allows us to compute the predictions of single-field slow-roll inflation directly from the constrained parameter values. We illustrate the resulting predictions for the parameters that characterize the scalar power spectrum and place constraints on several representative inflationary models. Our analysis shows that monomial-potential inflation is disfavored, while models with concave potentials, such as the Starobinsky model and brane inflation, are preferred. From the constraints on the slow-roll parameters, we obtain a tensor spectral index in the single-field slow-roll framework that is very small,

\begin{document}$ |n_t|\lesssim 4.9\times 10^{-3} $\end{document}

, a value that will be challenging to measure with CMB data alone in the foreseeable future. Moreover, the absolute value of the derived running of the tensor spectral index does not exceed 1.91 × 10^-4 at 95% confidence level, based on the combination of CMB+BAO+DESI datasets.

核实验

Charge Separation Measurements in Au+Au collisions at ${ \sqrt{{\boldsymbol s}_{\boldsymbol{NN}}}} $ = 7.7–200 GeV in Search of the Chiral Magnetic Effect

The STAR Collaboration

Published:

Abstract:
The chiral magnetic effect in heavy-ion collisions predicts an electric charge separation along the direction of a strong magnetic field, which indicates local parity (

\begin{document}$ {\cal{P}} $\end{document}

) and charge-conjugation-parity (

\begin{document}$ {\cal{CP}} $\end{document}

) violations in strong interactions. We report measurements of electric charge separation signals perpendicular to the spectator event plane in Au+Au collisions using high-statistics data from RHIC Beam Energy Scan II and top-RHIC energy (

\begin{document}$ \sqrt{s_{NN}}=200 $\end{document}

GeV) runs. A novel event shape selection method is employed to suppress the flow-induced background. The residual charge-separation signal fractions near the zero-flow limit are positive in Au+Au collisions within the 20%–50% centrality range. The significance levels are

\begin{document}$ 2.8\sigma $\end{document}

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

, and

\begin{document}$ 3.2\sigma $\end{document}

\begin{document}$ \sqrt{s_{NN}} = $\end{document}

11.5, 14.6, and 19.6 GeV, respectively. At other beam energies, the signals are either statistically limited or consistent with zero.

PARTICLES AND FIELDS

The resonance effect for the CP asymmetry associated with the process ${\boldsymbol\omega{\bf\to}{\boldsymbol\pi}^+{\boldsymbol\pi}^-{\boldsymbol\pi}^{\bf 0} }$

Xi-Liang Yuan, Gang Lü, Na Wang, Chao Wang

Published: , doi: 10.1088/1674-1137/ad8ec2

Abstract:
The direct CP asymmetry in the weak decay process of hadrons is commonly attributed to the weak phase of the CKM matrix and the indeterminate strong phase. We propose a method to generate a significant phase difference through the interference between ρ and ω mesons, taking into account the G-parity allowed decay process of

\begin{document}$\omega \rightarrow \pi^{+}\pi^{-}\pi^{0}$\end{document}

and the G-parity-suppressed decay process of

\begin{document}$\rho^{0} \rightarrow \pi^{+}\pi^{-}\pi^{0}$\end{document}

in B meson decays. This interference can lead to notable changes in the CP asymmetry within the interference region. Additionally, we calculate the integral results for different phase space regions of the four-body decay process. We hope that our work provides valuable theoretical guidance for future experimental investigations on CP asymmetry in these decays.

IF: 3.1

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