arXiv subjects

R. Farinelli

Publications and source records attributed to R. Farinelli.

At least 163 records · Page 9Linked to original sources

arXiv2025

Precise Measurement of the $χ_{c0}$ Resonance Parameters and Branching Fractions of $χ_{c0,c2}\toπ^+π^-/K^+K^-$

By analyzing a $ψ(3686)$ data sample containing $(107.7\pm0.6)\times10^{6}$ events taken with the BESIII detector at the BEPCII storage ring in 2009, the $χ_{c0}$ resonance parameters are precisely measured using $χ_{c0,c2} \to π^+π^-/K^+K^-$ events. The mass of $χ_{c0}$ is determined to be $M(χ_{c0})=(3415.63\pm0.07\pm0.07\pm0.07$)~MeV/$c^2$, and its full width is $Γ(χ_{c0})=(12.52\pm0.12\pm0.13)~{\rm MeV}$, where the first uncertainty is statistical, the second systematic, and the third for mass comes from $χ_{c2}$ mass uncertainty. These measurements improve the precision of $χ_{c0}$ mass by a factor of four and width by one order of magnitude over the previous individual measurements, and significantly boost our knowledge about the charmonium spectrum. Together with additional $(345.4\pm2.6)\times10^{6}$ $ψ(3686)$ data events taken in 2012, the decay branching fractions of $χ_{c0,c2}\toπ^+π^-/K^+K^-$ are measured as well, with precision improved by a factor of three compared to previous measurements. These $χ_{c0}$ decay branching fractions provide important inputs for the study of glueballs.

hep-ex↗

arXiv2025

Observation of Three Resonant Structures in the Cross Section of $e^+e^-\toπ^+π^- h_c$

Using $e^+e^-$ collision data collected with the BESIII detector operating at the Beijing Electron Positron Collider, the cross section of $e^+e^-\to π^+π^- h_c$ is measured at 59 points with center-of-mass energy $\sqrt{s}$ ranging from $4.009$ to $4.950~\mathrm{GeV}$ with a total integrated luminosity of $22.2~\mathrm{fb}^{-1}$. The cross section between $4.3$ and $4.45~\mathrm{GeV}$ exhibits a plateau-like shape and drops sharply around $4.5~\mathrm{GeV}$, which cannot be described by two resonances only. Three coherent Breit-Wigner functions are used to parameterize the $\sqrt{s}$-dependent cross section line shape. The masses and widths are determined to be $M_1=(4223.6_{-3.7-2.9}^{+3.6+2.6})~\mathrm{MeV}/c^2$, $Γ_1=(58.5_{-11.4-6.5}^{+10.8+6.7})~\mathrm{MeV}$, $M_2=(4327.4_{-18.8-9.3}^{+20.1+10.7})~\mathrm{MeV}/c^2$, $Γ_2=(244.1_{-27.1-18.3}^{+34.0+24.2})~\mathrm{MeV}$, and $M_3=(4467.4_{-5.4-2.7}^{+7.2+3.2})~\mathrm{MeV}/c^2$, $Γ_3=(62.8_{-14.4-7.0}^{+19.2+9.9})~\mathrm{MeV}$. The first uncertainties are statistical and the second are systematic. The inclusion of the relatively narrower third component proves crucial for reproducing the drop at around 4.5~GeV. The statistical significance of the three-resonance assumption over the two-resonance assumption is greater than $5σ$.

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arXiv2025

Euclid preparation. Spatially resolved stellar populations of local galaxies with Euclid: a proof of concept using synthetic images with the TNG50 simulation

The European Space Agency's Euclid mission will observe approximately 14,000 $\rm{deg}^{2}$ of the extragalactic sky and deliver high-quality imaging for many galaxies. The depth and high spatial resolution of the data will enable a detailed analysis of stellar population properties of local galaxies. In this study, we test our pipeline for spatially resolved SED fitting using synthetic images of Euclid, LSST, and GALEX generated from the TNG50 simulation. We apply our pipeline to 25 local simulated galaxies to recover their resolved stellar population properties. We produce 3 types of data cubes: GALEX + LSST + Euclid, LSST + Euclid, and Euclid-only. We perform the SED fitting tests with two SPS models in a Bayesian framework. Because the age, metallicity, and dust attenuation estimates are biased when applying only classical formulations of flat priors, we examine the effects of additional priors in the forms of mass-age-$Z$ relations, constructed using a combination of empirical and simulated data. Stellar-mass surface densities can be recovered well using any of the 3 data cubes, regardless of the SPS model and prior variations. The new priors then significantly improve the measurements of mass-weighted age and $Z$ compared to results obtained without priors, but they may play an excessive role compared to the data in determining the outcome when no UV data is available. The spatially resolved SED fitting method is powerful for mapping the stellar populations of galaxies with the current abundance of high-quality imaging data. Our study re-emphasizes the gain added by including multiwavelength data from ancillary surveys and the roles of priors in Bayesian SED fitting. With the Euclid data alone, we will be able to generate complete and deep stellar mass maps of galaxies in the local Universe, thus exploiting the telescope's wide field, NIR sensitivity, and high spatial resolution.

astro-ph.GA↗

arXiv2025

Study of $f_1(1420)$ and $η(1405)$ in the decay $J/ψ\to γπ^{0}π^{0}π^{0}$

A partial-wave analysis is performed on the decay $J/ψ\toγπ^{0}π^{0}π^{0}$ within the $π^{0}π^{0}π^{0}$ invariant-mass region below 1.6 GeV$/c^{2}$, using $(10.09~\pm~0.04)\times10^{9} ~J/ψ$ events collected with the BESIII detector. Significant isospin-violating decays of $η(1405)$ and $f_1(1420)$ into $f_0(980)π^{0}$ are observed. For the first time, three axial-vectors, $f_1(1285)$, $f_1(1420)$ and $f_1(1510)$, are observed to decay into $π^{0}π^{0}π^{0}$. The product branching fractions of these resonances are reported.

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arXiv2025

Observation of resonant contribution to the $e^+e^-\to Ω^{-}\barΩ^{+}$ around 4.2 GeV and evidence of $ψ(3770)\to Ω^{-}\barΩ^{+}$

Using $e^+e^-$ collision data corresponding to a total integrated luminosity of 22.7 fb$^{-1}$, collected at center-of-mass energies between 3.7 and 4.7 GeV with the BESIII detector, we present a measurement of energy-dependent cross sections and effective form factors for the process of $e^+e^-\to Ω^{-}\barΩ^+$. By conducting a fit to the cross sections of $e^+e^-\to Ω^{-}\barΩ^+$ considering the continuum and resonant contributions, a clear resonant structure in the spectrum around 4.2 GeV is observed for the first time with a statistical significance exceeding 10$σ$, and it can be well described with the line shape of the $Y(4230)$ and $Y(4320)$ observed in $e^+e^-\to π^{+}π^{-}J/ψ$. Evidence for the decay $ψ(3770) \to Ω^-\barΩ^{+}$ is observed with a statistical significance of 4.4$σ$ by analyzing the measured cross sections together with earlier BESIII results, and the branching fraction is firstly measured to be $(4.0\pm1.0\pm0.6)$ $\times$ $10^{-5}$, where the first uncertainty is statistical and the second is systematic.

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arXiv2025

Measurement of the phase between strong and electromagnetic amplitudes in the decay $J/ψ\toϕη$

The first direct measurement of the relative phase between the strong and electromagnetic amplitudes for a $J/ψ$ decaying into a vector-pseudoscalar final state is performed using 26 energy points of $e^+e^-$ annihilation data between $3.00\ \text{GeV}$ and \mbox{3.12 GeV}. The data sets were collected by the BESIII detector with a total integrated luminosity of 452 pb$^{-1}$. By investigating the interference pattern in the cross section lineshape of $e^+e^-\toϕη$, the relative phase between the strong and electromagnetic amplitudes of $J/ψ$ decay is determined to be within $[133^\circ,228^\circ]$ at 68\% confidence level.

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arXiv2025

Euclid: Forecasts on $Λ$CDM consistency tests with growth rate data

The large-scale structure (LSS) of the Universe is an important probe for deviations from the canonical cosmological constant $Λ$ and cold dark matter ($Λ$CDM) model. A statistically significant detection of any deviations would signify the presence of new physics or the breakdown of any number of the underlying assumptions of the standard cosmological model or possible systematic errors in the data. In this paper, we quantify the ability of the LSS data products of the spectroscopic survey of the Euclid mission, together with other contemporary surveys, to improve the constraints on deviations from $Λ$CDM in the redshift range $0<z<1.75$. We consider both currently available growth rate data and simulated data with specifications from Euclid and external surveys, based on $Λ$CDM and a modified gravity (MoG) model with an evolving Newton's constant (denoted $μ$CDM), and carry out a binning method and a machine learning reconstruction, based on genetic algorithms (GAs), of several LSS null tests. Using the forecast Euclid growth data from the spectroscopic survey in the range $0.95<z<1.75$, we find that in combination with external data products (covering the range $0<z<0.95$), Euclid will be able to improve on current constraints of null tests of the LSS on average by a factor of eight when using a binning method and a factor of six when using the GAs. Our work highlights the need for synergies between Euclid and other surveys, but also the usefulness of statistical analyses, such as GAs, in order to disentangle any degeneracies in the cosmological parameters. Both are necessary to provide tight constraints over an extended redshift range and to probe for deviations from the $Λ$CDM model.

astro-ph.CO↗

arXiv2025

Measurement of the branching fractions of the Cabibbo-favored decays $Λ_{c}^{+}\toΛK_{S}^{0}K^{+}$ and $Λ_{c}^{+}\toΞ^{0}K_{S}^{0}π^{+}$ and search for $Λ_{c}^{+}\toΣ^{0} K_{S}^{0}K^{+}$

Based on $e^{+}e^{-}$ collision data corresponding to an integrated luminosity of about 4.5 fb$^{-1}$ collected at center-of-mass energies between 4599.53 MeV and 4698.82 MeV with the BESIII detector, the absolute branching fraction of the Cabibbo-favored decay $Λ_{c}^{+}\toΛK_{S}^{0}K^{+}$ is measured to be $(3.12\pm0.46\pm0.15)\times10^{-3}$. Combined with a previous measurement from the BESIII Collaboration, the branching fraction of the decay $Λ_{c}^{+}\toΛK_{S}^{0}K^{+}$ is calculated to be $(3.07\pm0.26\pm0.13)\times10^{-3}$. The decay $Λ_{c}^{+}\toΞ^{0}K_{S}^{0}π^{+}$ is observed for the first time with a statistical significance of $6.6σ$, and its branching fraction is determined to be $(3.70\pm0.60\pm0.21)\times10^{-3}$. In addition, a search for the decay $Λ_{c}^{+}\toΣ^{0} K_{S}^{0}K^{+}$ is performed and its branching fraction is determined to be $(0.80^{+0.28}_{-0.24}\pm0.16)\times10^{-3}$, corresponding to an upper limit of $1.28\times10^{-3}$ at $90\%$ confidence level. These measurements provide new information that can be used to distinguish between theoretical models.

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arXiv2025

Euclid preparation: Expected constraints on initial conditions

The Euclid mission of the European Space Agency will deliver galaxy and cosmic shear surveys, which will be used to constrain initial conditions and statistics of primordial fluctuations. We present highlights for the Euclid scientific capability to test initial conditions beyond LCDM with the main probes, i.e. 3D galaxy clustering from the spectroscopic survey, the tomographic approach to 3x2pt statistics from photometric galaxy survey, and their combination. We provide Fisher forecasts from the combination of Euclid spectroscopic and photometric surveys for spatial curvature, running of the spectral index of the power spectrum of curvature perturbations, isocurvature perturbations, and primordial features. For the parameters of these models we also provide the combination of Euclid forecasts (pessimistic and optimistic) with current and future measurements of the cosmic microwave background (CMB) anisotropies., i.e. Planck, the Simons Observatory (SO), and CMB-S4. We provide Fisher forecasts for how the power spectrum and bispectrum from the Euclid spectroscopic survey will constrain the local, equilateral, and orthogonal shapes of primordial non-Gaussianity. We also review how Bayesian field-level inference of primordial non-Gaussianity can constrain local primordial non-Gaussianity. We show how Euclid, with its unique combination of the main probes, will provide the tightest constraints on low redshift to date. By targeting a markedly different range in redshift and scale, Euclid's expected uncertainties are complementary to those obtained by CMB primary anisotropy, returning the tightest combined constraints on the physics of the early Universe.

astro-ph.CO↗

arXiv2025

Amplitude analysis of $ψ(3686)\to γK_S^0 K_S^0 $

Using $(2712\pm14)\times10^6$ $ψ(3686)$ events collected with the BESIII detector, we perform the first amplitude analysis of the radiative decay $ψ(3686)\to γK_S^0 K_S^0$ within the mass region $M_{K_S^0 K_S^0 }<2.8$ GeV/$c^2$. Employing a one-channel K-matrix approach for the description of the dynamics of the $K^0_S K^0_S$ system, the data sample is well described with four poles for the $f_0$-wave and three poles for the $f_2$-wave. The determined pole positions are consistent with those of well-established resonance states. The observed $f_0$ and $f_{2}$ states are found to be in agreement with those produced in radiative $J/ψ$ decays. The production behaviors of $f_0$ and $f_2$ poles in $ψ(3686)\toγK_S^0 K_S^0$ are qualified with their residues and the converted branching fractions. By comparing with $J/ψ\toγK_S^0 K_S^0$ decay, the ratios $\frac{\mathcal{B}(ψ(3686)\toγf_{0,2})}{\mathcal{B}(J/ψ\toγf_{0,2})}$ are determined, which provides crucial experimental inputs on the internal structure of the $f_{0,2}$ states, especially their potential mixing with glueball components.

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arXiv2025

First Measurement of the Decay Dynamics in the Semileptonic Transition of the $D^{+(0)}$ into the Axial-vector Meson $\bar K_1(1270)$

Using $e^+e^-$ data taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, corresponding to an integrated luminosity of 20.3 fb$^{-1}$, we report the first measurement of the decay dynamics of the semileptonic decays $D^{+(0)}\to K^-π^+π^{0(-)} e^+ν_e$. The amplitude analysis gives the hadronic form factors of the semileptonic $D$ transitions into the axial-vector meson $\bar{K}_1(1270)$ to be $r_A=(-11.2\pm1.0_{\rm stat}\pm0.9_{\rm syst})\times10^{-2}$ and $r_V = (-4.3\pm 1.0_{\rm stat}\pm2.5_{\rm syst})\times 10^{-2}$. This is the first in the semileptonic decays of heavy mesons into axial-vector mesons. The angular analysis yields an up-down asymmetry $\mathcal{A}^\prime_{ud} = 0.01\pm0.11$, which is consistent with the Standard Model prediction. In addition, the branching fractions of $D^+\to \bar K_1(1270)^0 e^+ν_e$ and $D^0\to K_1(1270)^- e^+ν_e$ are determined with improved precision to be $(2.27\pm0.11_{\rm stat}\pm0.07_{\rm syst}\pm0.07_{\rm input})\times10^{-3}$ and $(1.02\pm0.06_{\rm stat}\pm0.06_{\rm syst}\pm0.03_{\rm input})\times10^{-3}$, respectively. No significant signals of $D^+\to \bar K_1(1400)^0 e^+ν_e$ and $D^0\to K_1(1400)^- e^+ν_e$ are observed and their branching fraction upper limits are set as $1.4\times10^{-4}$ and $0.7\times10^{-4}$ at 90\% confidence level, respectively.

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arXiv2025

Euclid VI. NISP-P optical ghosts

The Near-Infrared Spectrometer and Photometer (NISP) onboard Euclid includes several optical elements in its path, which introduce artefacts into the data from non-nominal light paths. To ensure uncontaminated source photometry, these artefacts must be accurately accounted for. This paper focuses on two specific optical features in NISP's photometric data (NISP-P): ghosts caused by the telescope's dichroic beamsplitter, and the bandpass filters within the NISP fore-optics. Both ghost types exhibit a characteristic morphology and are offset from the originating stars. The offsets are well modelled using 2D polynomials, with only stars brighter than approximately 10 magnitudes in each filter producing significant ghost contributions. The masking radii for these ghosts depend on both the source-star brightness and the filter wavelength, ranging from 20 to 40 pixels. We present the final relations and models used in the near-infrared (NIR) data pipeline to mask these ghosts for Euclid's Quick Data Release (Q1).

astro-ph.IM↗

arXiv2025

Euclid preparation. Overview of Euclid infrared detector performance from ground tests

The paper describes the objectives, design and findings of the pre-launch ground characterisation campaigns of the Euclid infrared detectors. The pixel properties, including baseline, bad pixels, quantum efficiency, inter pixel capacitance, quantum efficiency, dark current, readout noise, conversion gain, response nonlinearity, and image persistence were measured and characterised for each pixel. We describe in detail the test flow definition that allows us to derive the pixel properties and we present the data acquisition and data quality check software implemented for this purpose. We also outline the measurement protocols of all the pixel properties presented and we provide a comprehensive overview of the performance of the Euclid infrared detectors as derived after tuning the operating parameters of the detectors. The main conclusion of this work is that the performance of the infrared detectors Euclid meets the requirements. Pixels classified as non-functioning accounted for less than 0.2% of all science pixels. IPC coupling is minimal and crosstalk between adjacent pixels is less than 1% between adjacent pixels. 95% of the pixels show a QE greater than 80% across the entire spectral range of the Euclid mission. The conversion gain is approximately 0.52 ADU/e-, with a variation less than 1% between channels of the same detector. The reset noise is approximately equal to 23 ADU after reference pixels correction. The readout noise of a single frame is approximately 13 $e^-$ while the signal estimator noise is measured at 7 $e^-$ in photometric mode and 9 $e^-$ in spectroscopic acquisition mode. The deviation from linear response at signal levels up to 80 k$e^-$ is less than 5% for 95% of the pixels. Median persistence amplitudes are less than 0.3% of the signal, though persistence exhibits significant spatial variation and differences between detectors.

astro-ph.IM↗

arXiv2025

Observation of the electromagnetic radiative decays of the \boldmath{$Λ(1520)$} and \boldmath{$Λ(1670)$} to \boldmath{$γΣ^0$}

Using $(10087\pm 44)\times10^6$ $J/ψ$ events collected with the BESIII detector, we report the first observation of the electromagnetic radiative decays of the $Λ(1520)$ and $Λ(1670)$ to $γΣ^0$, with a statistical significance of $16.6σ$ and $23.5σ$, respectively. The ratio of the branching fractions $\frac{\mathcal{B}(Λ(1520)\toγΛ)}{\mathcal{B}(Λ(1520)\toγΣ^0)}$ is determined to be $2.88\pm0.27(\text{stat.})\pm0.21(\text{syst.})$, which is in good agreement with flavor SU(3) symmetry. The branching fraction of $Λ(1520)\toγΣ^0$ is measured to be $\mathcal{B}(Λ(1520)\toγΣ^0)=(2.95\pm0.28(\text{stat.})\pm0.56(\text{syst.}))\times 10^{-3}$, corresponding to a partial width of $Γ(Λ(1520)\toγΣ^0)=(47.2\pm4.5(\text{stat.})\pm9.0(\text{syst.}))$ keV, which is inconsistent with predictions from the relativized constituent quark model and the Algebraic model. Additionally, we observe a clear resonant structure in the $γΣ^0$ mass spectrum around 1.67 GeV/$c^2$, attributed to the $Λ(1670)$. The product branching fraction $\mathcal{B}(J/ψ\to\barΛΛ(1670)+c.c.)\times\mathcal{B}(Λ(1670)\toγΣ^0)$ is measured for the first time as $(5.39\pm0.29(\text{stat.})\pm 0.44(\text{syst.}))\times 10^{-6}$. However, no corresponding structure is seen in the $γΛ$ mass spectrum, so an upper limit on the product branching fraction $\mathcal{B}(J/ψ\to\barΛΛ(1670)+c.c.)\times\mathcal{B}(Λ(1670)\toγΛ)$ is determined to be $5.97\times10^{-7}$ at the 90\% confidence level.

hep-ex↗

arXiv2025

Euclid: Early Release Observations. Weak gravitational lensing analysis of Abell 2390

The Euclid space telescope of the European Space Agency (ESA) is designed to provide sensitive and accurate measurements of weak gravitational lensing distortions over wide areas on the sky. Here we present a weak gravitational lensing analysis of early Euclid observations obtained for the field around the massive galaxy cluster Abell 2390 as part of the Euclid Early Release Observations programme. We conduct galaxy shape measurements using three independent algorithms (LensMC, KSB+, and SourceXtractor++). Incorporating multi-band photometry from Euclid and Subaru/Suprime-Cam, we estimate photometric redshifts to preferentially select background sources from tomographic redshift bins, for which we calibrate the redshift distributions using the self-organising map approach and data from the Cosmic Evolution Survey (COSMOS). We quantify the residual cluster member contamination and correct for it in bins of photometric redshift and magnitude using their source density profiles, including corrections for source obscuration and magnification. We reconstruct the cluster mass distribution and jointly fit the tangential reduced shear profiles of the different tomographic bins with spherical Navarro--Frenk--White profile predictions to constrain the cluster mass, finding consistent results for the three shape catalogues and good agreement with earlier measurements. As an important validation test we compare these joint constraints to mass measurements obtained individually for the different tomographic bins, finding good consistency. More detailed constraints on the cluster properties are presented in a companion paper that additionally incorporates strong lensing measurements. Our analysis provides a first demonstration of the outstanding capabilities of Euclid for tomographic weak lensing measurements.

astro-ph.CO↗

arXiv2025

Search for the lepton number violating process $J/ψ\to K^+K^+e^-e^- +c.c.$

Based on $(10087\pm 44)\times10^{6}$ $J/ψ$ events collected with the BESIII detector, we search for the lepton number violating decay $J/ψ\to K^+K^+e^-e^- + c.c.$ for the first time. The upper limit on the branching fraction of this decay is set to be $2.1 \times 10^{-9}$ at the 90$\%$ confidence level with a frequentist method. This is the first search for $J/ψ$ decays with the lepton number change by two, offering valuable insights into the underlying physical processes.

hep-ex↗

arXiv2025

Study of the light scalar $a_{0}(980)$ through the decay $D^{0} \to a_{0}(980)^-e^{+} ν_{e}$ with $a_{0}(980)^- \to ηπ^-$

Using 7.93 ${\rm fb^{-1}}$ of $e^+e^-$ collision data collected at a center-of-mass energy of 3.773 ${\rm GeV}$ with the BESIII detector, we present an analysis of the decay $D^{0} \to ηπ^- e^+ ν_{e}$. The branching fraction of the decay $D^{0} \to a_{0}(980)^{-} e^+ ν_{e}$ with $a_{0}(980)^{-} \to ηπ^{-}$ is measured to be $(0.86\pm0.17_{\text{stat}}\pm0.05_{\text{syst}})\times 10^{-4}$. The decay dynamics of this process is studied with a single-pole parameterization of the hadronic form factor and the Flatté formula describing the $a_0(980)$ line shape in the differential decay rate. The product of the form factor $f^{ a_0}_{+}(0)$ and the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cd}|$ is determined for the first time with the result $f^{ a_0}_+(0)|V_{cd}|=0.126\pm0.013_{\rm stat}\pm0.003_{\rm syst}$.

hep-ex↗

arXiv2025

Study of the electromagnetic Dalitz decay $J/ψ\to e^+e^- π^0$

We report the first measurement of the di-electron invariant mass dependent transition form factor in the electromagnetic Dalitz decay $J/ψ\to e^+e^- π^0$ using $(10087 \pm 44) \times 10^6$ $J/ψ$ events collected by the BESIII detector. A clear $ρ-ω$ interference structure is observed, consistent with the pion form factor, which offers a novel approach to extract the hadronic vacuum polarization contribution to the anomalous muon magnetic moment ($a_μ$) and refine the predictions of the Vector Meson Dominance (VMD) model and hadronic light-by-light contribution to $a_μ$. By taking into account the contribution of this $ρ-ω$ interference structure, the branching fraction of $J/ψ\to e^+e^- π^0$ in the full $e^+e^-$ invariant mass range is also measured for the first time to be $(8.06 \pm 0.31 (\rm{stat}) \pm 0.38 (\rm{syst}))\times 10^{-7}$, approximately twice the non-resonant VMD prediction.

hep-ex↗