arXiv subjects

P. Adlarson

Publications and source records attributed to P. Adlarson.

At least 361 records · Page 20Linked to original sources

arXiv2025

Evidence of doubly OZI-suppressed decay $η_{c} \to ωϕ$ in the radiative decay $J/ψ\to γη_{c}$

Using a sample of $(10087\pm44) \times 10^{6}$ $J/ψ$ events collected with the BESIII detector at the BEPCII collider, the first evidence for the doubly OZI-suppressed decay $η_{c} \to ωϕ$ is reported with a significance of 4.0$σ$. The branching fraction of $η_{c} \to ωϕ$ is measured to be $\mathcal{B}(η_{c} \to ωϕ) = (3.86 \pm 0.92 \pm 0.62) \times 10^{-5}$, where the first uncertainty is statistical and the second is systematic. This result provides valuable insights into the underlying mechanisms of charmonium decays, particularly for processes such as $η_{c} \to VV$ (where $V$ represents a vector meson).

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arXiv2025

First determination of the spin-parity of $Ξ_{c}(3055)^{+,0}$ baryons

The ${Ξ_{b}^{0(-)}\toΞ_{c}(3055)^{+(0)}(\to D^{+(0)}Λ)π^{-}}$ decay chains are observed, and the spin-parity of $Ξ_{c}(3055)^{+(0)}$ baryons is determined for the first time. The measurement is performed using proton-proton collision data at a center-of-mass energy of $\sqrt{s}=13\,\text{TeV}$, corresponding to an integrated luminosity of $5.4\,\text{fb}^{-1}$, recorded by the~$\text{LHCb}$ experiment between 2016 and 2018. The spin-parity of the $Ξ_{c}(3055)^{+(0)}$ baryons is determined to be $3/2^{+}$ with a significance of more than $6.5σ$ ($3.5σ$) compared to all other tested hypotheses. The up-down asymmetries of the ${Ξ_{b}^{0(-)}\toΞ_{c}(3055)^{+(0)}π^{-}}$ transitions are measured to be $-0.92\pm0.10\pm0.05$ ($-0.92\pm0.16\pm0.22$), consistent with maximal parity violation, where the first uncertainty is statistical and the second is systematic. These results support the hypothesis that the $Ξ_{c}(3055)^{+(0)}$ baryons correspond to the first $D$-wave $λ$-mode excitation of the $Ξ_{c}$ flavor triplet.

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arXiv2025

Measurement of the branching fractions of doubly Cabibbo-suppressed $D$ decays

By analyzing $e^+e^-$ collision data collected 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 measure the branching fractions of the doubly Cabibbo-suppressed (DCS) decays $D^0\to K^+π^-$, $D^0\to K^+π^-π^-π^+$, $D^0\to K^+π^-π^0$, $D^0\to K^+π^-π^0π^0$, $D^+\to K^+π^+π^-$, and $D^+\to K^+K^+K^-$. We also perform the first searches for $D^0\to K^+π^-η$, $D^0\to K^+π^-π^0η$, $D^+\to K^+π^+π^-η$, $D^{+} \to K^{+} \left(π^{+} π^{-} η\right)_{{\rm non}-η^{\prime}}$, and $D^+\to K^+ηη$ and report the first observations and evidence for some of these final states. Combining the measurements with the world averages of the corresponding Cabibbo-favored (CF) decays, the ratios of the DCS/CF branching fractions are obtained. For the $D^{+} \to K^{+} \left(π^{+} π^{-} η\right)_{{\rm non}-η^{\prime}}$ decay, the ratio is significantly larger than the corresponding ratios of the other DCS decays.

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arXiv2025

Measurement of $ϕ(1020)$ meson production in fixed-target $\textit{p}$Ne collisions at $\sqrt{s_{NN}}$ = 68.5 GeV

The first measurement of $ϕ(1020)$ meson production in fixed-target $p$Ne collisions at $\sqrt{s_{NN}}=68.5$ GeV is presented. The $ϕ(1020)$ mesons are reconstructed in their $K^{+}K^{-}$ decay in a data sample consisting of proton collisions on neon nuclei at rest, corresponding to an integrated luminosity of $21.7 \pm 1.4$ nb$^{-1}$, collected by the LHCb detector at CERN. The $ϕ(1020)$ production cross-section in the centre-of-mass rapidity range of $-1.8<y^*<0$ and transverse momentum range of $800<p_{T}<6500$ MeV/c is found to be $σ=182.7\pm2.7~\text{(stat.)}\pm14.1~\text{(syst)}~μ$b/nucleon. A double-differential measurement of the cross-section is also provided in four regions of rapidity and six regions of transverse momentum of the $ϕ(1020)$ meson and compared with the predictions from Pythia and EPOS4, which are found to underestimate the experimental values.

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arXiv2025

Cross section measurement of $e^+e^-\to ηψ(2S)$ and search for $e^+e^-\toη\tilde{X}(3872)$

The energy-dependent cross section for $e^+e^-\to ηψ(2S)$ is measured at eighteen center of mass energies from 4.288 GeV to 4.951 GeV using the BESIII detector. Using the same data samples, we also perform the first search for the reaction $e^+e^-\toη\tilde{X}(3872)$, but no evidence is found for the $\tilde{X}(3872)$ in the $π^+π^- J/ψ$ mass distribution. At each of the eighteen center of mass energies, upper limits at the 90\% confidence level on the cross section for $e^+e^-\toηψ(2S)$ and on the product of the $e^+e^-\toη\tilde{X}(3872)$ cross section with the branching fraction of $\tilde{X}(3872)\toπ^+π^- J/ψ$ are reported.

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arXiv2025

Observation of the decay $ψ(3686)\rightarrow Σ^{0}\barΣ^{0}ω$

Using a dataset of $(27.12\pm 0.14)\times 10^{8}$ $ψ(3686)$ events collected by the BESIII detector operating at the BEPCII collider, we report the first observation of the decay $ψ(3686)\toΣ^{0}\barΣ^{0}ω$ with a statistical significance of 8.9$σ$. The measured branching fraction is $(1.24 \pm 0.16_{\textrm{stat}} \pm 0.11_{\textrm{sys}}) \times 10^{-5}$, where the first uncertainty is statistical and the second is systematic. Additionally, we investigate potential intermediate states in the invariant mass distributions of $Σ^{0}ω$, $\barΣ^{0}ω$ and $Σ^{0}\barΣ^{0}$. A hint of a resonance is observed in the invariant mass distribution of $M_{Σ^{0}(\barΣ^{0})ω}$, located around 2.06 GeV/$c^2$, with a significance of 2.5$σ$.

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arXiv2025

Stringent test of $CP$ symmetry in $Σ^+$ hyperon decays

The non-leptonic two-body weak decays $Σ^{+} \to p π^{0}$ and $\barΣ^{-} \to \bar{p} π^{0}$ are investigated, utilizing $(1.0087\pm0.0044)\times10^{10}$ $J/ψ$ events and $(2.7124\pm0.0143)\times10^{9}$ $ψ(3686)$ events collected by BESIII experiment. The precision of the weak-decay parameters for the decays $Σ^{+} \to p π^{0}$ ($α_{0}$) and $\barΣ^{-} \to \bar{p} π^{0}$ ($\barα_{0}$) is improved by a factor of three compared to the previous world average. Furthermore, the quantum-entangled $Σ^{+}\barΣ^{-}$ system enables the most precise test of $CP$ symmetry for the decay $Σ^+\to pπ^0$, through the asymmetry observable $A_{CP}=(α_{0}+\barα_{0})/(α_{0}-\barα_{0})$ that is measured to be $-0.0118\pm0.0083_{\rm stat}\pm0.0028_{\rm syst}$. Assuming $CP$ conservation, the average decay parameter is determined to be ${\left< α_{\rm 0}\right>} = (α_0-\barα_0)/2=-0.9869\pm0.0011_{\rm stat}\pm0.0016_{\rm syst}$, which is the most precise measurement of the asymmetry decay parameters in baryon sectors. The angular dependence of the ratio of the polarization of the $Σ^+$ in both $J/ψ$ and $ψ(3686)$ decays is studied for the first time.

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arXiv2025

Observation of $D^+\toη^\primeμ^+ν_μ$ and First Study of $D^+\to η^\prime \ell^+ν_\ell$ Decay Dynamics

Using $20.3\,\rm fb^{-1}$ of $e^+e^-$ collision data collected at the center-of-mass energy 3.773\,GeV with the BESIII detector, we report the first observation of the semileptonic decay $D^+\to η^\prime μ^+ν_μ$ with significance of $8.6σ$ including systematic uncertainties, and an improved measurement of $D^+\to η^\prime e^+ν_e$. The branching fractions of $D^+\to η^\prime μ^+ν_μ$ and $D^+\to η^\prime e^+ν_e$ are determined to be $(1.92\pm0.28_{\rm stat}\pm 0.08_{\rm syst})\times 10^{-4}$ and $(1.79\pm0.19_{\rm stat}\pm 0.07_{\rm syst})\times 10^{-4}$, respectively. The ratio of the two branching fractions is determined to be ${\mathcal R}_{μ/e}=1.07\pm0.19_{\rm stat}\pm 0.03_{\rm syst}$, which agrees with the theoretical expectation of lepton flavor universality within the Standard Model.From an analysis of the $D^+\to η^\prime \ell^+ν_\ell$ decay dynamics, the product of the hadronic form factor $f_+^{η^{\prime}}(0)$ and the CKM matrix element $|V_{cd}|$ is measured for the first time, giving $f^{η^\prime}_+(0)|V_{cd}| = (5.92\pm0.56_{\rm stat}\pm0.13_{\rm syst})\times 10^{-2}$. The $η-η^\prime$ mixing angle in the quark flavor basis is determined to be $ϕ_{\rm P} =(39.8\pm0.8_{\rm stat}\pm0.3_{\rm syst})^\circ$.

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arXiv2025

First evidence for direct CP violation in beauty to charmonium decays

The $C\!P$ asymmetry and branching fraction of the CKM-suppressed decay $B^+\!\to J\mskip -3mu/\mskip -2muψ\,π^+$ are precisely measured relative to the favoured decay $B^+\!\to J\mskip -3mu/\mskip -2muψ\,K^+$, using a sample of proton-proton collision data corresponding to an integrated luminosity of $5.4~\mathrm{fb}^{-1}$ recorded at center-of-mass energy of $13~\mathrm{TeV}$ during 2016--2018. The results of the $C\!P$ asymmetry difference and branching fraction ratio are \begin{align*} Δ\mathcal{A}^{C\!P} &\equiv \mathcal{A}^{C\!P}(B^+ \to J\mskip -3mu/\mskip -2muψ\,π^+) - \mathcal{A}^{C\!P}(B^+ \to J\mskip -3mu/\mskip -2muψ\,K^+) = (1.29 \pm 0.49 \pm 0.08) \times 10^{-2}, \end{align*} \begin{equation*} \mathcal{R}_{π/K} \equiv \frac{\mathcal{B}(B^+ \!\to J\mskip -3mu/\mskip -2muψ\,π^+)}{\mathcal{B}(B^+ \!\to J\mskip -3mu/\mskip -2muψ\,K^+)} = (3.852 \pm 0.022 \pm 0.018) \times 10^{-2}. \end{equation*} where the first uncertainties are statistical and the second systematic. A combination with previous LHCb results based on data collected at $7$ and $8~\mathrm{TeV}$ in 2011 and 2012 yields $Δ\mathcal{A}^{C\!P} = (1.42 \pm 0.43 \pm 0.08) \times 10^{-2}$ and $\mathcal{R}_{π/K} = (3.846 \pm 0.018 \pm 0.018) \times 10^{-2}$. The combined $Δ\mathcal{A}^{C\!P}$ value deviates from zero by 3.2 standard deviations, providing the first evidence for direct $C\!P$ violation in the amplitudes of beauty decays to charmonium final states.

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arXiv2025

Measurement of Born cross section of $e^+e^-\toΣ^0\barΣ^0$ at $\sqrt{s} = 3.50-4.95$ GeV

Using $e^+e^-$ collision data collected with the BESIII detector at the BEPCII collider at thirty-two center-of-mass energies from 3.50 to 4.95 GeV, corresponding to an integrated luminosity of 25 $\rm{fb^{-1}}$, we measure the Born cross section of the $e^+e^-\toΣ^0\barΣ^0$ reaction and the effective form factor. No significant charmonium(-like) state, i.e., $ψ(3770)$, $ψ(4040)$, $ψ(4160)$, $ψ(4230)$, $ψ(4360)$, $ψ(4415)$, or $ψ(4660)$, decaying into the $Σ^0\barΣ^0$ final state is observed by fitting the $e^+e^- \to Σ^0\barΣ^0$ dressed cross section. The upper limits for the product of the branching fraction and the electronic partial width at the 90% confidence level are provided for each assumed charmonium(-like) state. In addition, the ratios of the Born cross section and the effective form factor between the $e^+e^-\toΣ^0\barΣ^0$ and the $e^+e^-\toΣ^+\barΣ^-$ reactions are provided, which can be used to validate the prediction of the vector meson dominance model.

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arXiv2025

Search for a $1^{-+}$ molecular state via $e^{+}e^{-} \to γD^{+}_{s} D_{s1}^{-}(2536) +c.c.$

We search, for the first time, for an exotic molecular state with quantum numbers $J^{PC}=1^{-+}$, called $X$, via the process $e^{+}e^{-} \to γD^{+}_{s} D_{s1}^{-}(2536) +c.c.$ using data samples corresponding to a luminosity of $5.8~\mathrm{fb^{-1}}$ across center-of-mass energies from 4.612 to 4.951~GeV, collected with the BESIII detector operating at the BEPCII collider. No statistically significant signal is observed. The upper limits on the product of cross-section and branching fraction $σ({e^{+}e^{-} \to γX}) \times \mathcal{B}(X \to D^{+}_{s} D_{s1}^{-}(2536) +c.c.)$ at 90\% confidence level are reported for each energy point, assuming the $X$ mass to be 4.503~GeV/$c^{2}$ and the width 25, 50, 75, and 100~MeV, respectively.

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arXiv2025

Constraints on the photon polarisation in $b \to s γ$ transitions using $B_s^0 \rightarrow ϕe^+e^-$ decays

An angular analysis of the $B_s^0 \rightarrow ϕe^+e^-$ decay is performed using the proton-proton collision dataset collected between 2011 and 2018 by the LHCb experiment, corresponding to an integrated luminosity of $9\,{\rm fb}^{-1}$ at centre-of-mass energies of 7, 8 and $13\,{\rm TeV}$. The analysis is performed in the very low dielectron invariant mass-squared region between $0.0009$ and $0.2615\,{\rm GeV}^2\!/c^4$. The longitudinal polarisation fraction of the $ϕ$ meson is measured to be less than $11.5\%$ at $90\%$ confidence level. The $A_{\mathrm{T}}^{\mathcal{R}e C\!P}$ observable, which is related to the lepton forward-backward asymmetry, is measured to be $0.116 \pm 0.155 \pm 0.006$, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, $A_{\mathrm{T}}^{(2)}$ and $A_{\mathrm{T}}^{\mathcal{I}m C\!P}$, which are sensitive to the virtual photon polarisation, are found to be $-0.045 \pm 0.235 \pm 0.014$ and $0.002 \pm 0.247 \pm 0.016$, respectively. The results are consistent with Standard Model predictions.

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arXiv2025

Measurement of Branching Fractions for $Λ_{c}^{+} \rightarrow n K_{S}^{0} π^{+}$ and $Λ_{c}^{+} \rightarrow n K_{S}^{0} K^{+}$

Based on 4.5 fb$^{-1}$ of $e^{+}e^{-}$ collision data accumulated at center-of-mass energies between $4.600\,\mathrm{GeV}$ and $4.699\,\mathrm{GeV}$ with the BESIII detector, we measure the absolute branching fraction of the Cabibbo-favored decay $Λ_{c}^{+} \rightarrow n K_{S}^{0} π^{+}$ with the precision improved by a factor of 2.8 and report the first evidence for the singly-Cabibbo-suppressed decay $Λ_{c}^{+} \rightarrow n K_{S}^{0} K^{+}$. The branching fractions for $Λ_{c}^{+} \rightarrow n K_{S}^{0} π^{+}$ and $Λ_{c}^{+} \rightarrow n K_{S}^{0} K^{+}$ are determined to be $(1.86\pm0.08\pm0.04)\times10^{-2}$ and $\left(3.9^{+1.7}_{-1.4}\pm0.3\right)\times10^{-4}$, respectively, where the first uncertainties are statistical and the second ones are systematic.

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arXiv2025

Measurement of the branching fractions of $D^+ \to K^+K^-π^+π^+π^-$, $ϕπ^+π^+π^-$, $K^0_SK^+π^+π^-π^0$, $K^0_SK^+η$, and $K^0_SK^+ω$ decays

Using $20.3~\mathrm{fb}^{-1}$ of $e^+e^-$ collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector operating at the BEPCII collider, the branching fractions of three hadronic charm meson decays, $D^+\to ϕπ^+π^+π^-$, $D^+\to K^0_SK^+π^+π^-π^0$, and $D^+\to K^0_SK^+ω$, are measured for the first time to be $(0.54\pm0.19\pm0.02)\times 10^{-4}$, $(2.51\pm0.34\pm0.14)\times 10^{-4}$, and $(2.02\pm0.35\pm0.10)\times 10^{-4}$, respectively. Futhermore, the branching fractions of $D^+\to K^+K^-π^+π^+π^-$ and $D^+\to K^0_SK^+η$ are measured with improved precision, yielding values of $(0.66\pm0.11\pm0.03)\times 10^{-4}$ and $(2.27\pm0.22\pm0.05)\times 10^{-4}$, respectively.

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arXiv2025

Measurement of the CKM angle $γ$ in $B^{\pm} \to D K^*(892)^{\pm}$ decays

Measurements of $CP$ observables and the CKM angle $γ$ are performed in $B^{\pm} \to D K^*(892)^{\pm}$ decays, where $D$ represents a superposition of $D^0$ and $\overline{D}{}^0$ states, using the LHCb dataset collected during Run 1 (2011-2012) and Run 2 (2015-2018). A study of this channel is presented with the $D$ meson reconstructed in two-body final states $K^{\pm}π^{\mp}$, $K^+K^-$ and $π^+π^-$; four-body final states $K^{\pm}π^{\mp}π^{\pm}π^{\mp}$ and $π^+π^-π^+π^-$; and three-body final states $K^0_{S} π^+π^-$ and $K^0_{S} K^+ K^-$. This analysis includes the first observation of the suppressed $B^{\pm} \to [π^{\pm}K^{\mp}]_D K^{*\pm}$ and $B^{\pm} \to [π^{\pm}K^{\mp}π^{\pm}π^{\mp}]_D K^{*\pm}$ decays. The combined result gives $γ=(63\pm 13)^\circ$.

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arXiv2025

Measurement of cross sections of $e^+e^-\to K^0_S K^0_S ψ(3686)$ from $\sqrt{s}=$ 4.682 to 4.951 GeV

The process $e^+e^-\to K^0_S K^0_S ψ(3686)$ is studied by analyzing $e^+e^-$ collision data samples collected at eight center-of-mass energies ranging from 4.682 to 4.951 GeV with the BESIII detector operating at the BEPCII collider, corresponding to an integrated luminosity of $4.1~{\rm fb}^{-1}$. Observation of the $e^+e^-\to K^0_S K^0_S ψ(3686)$ process is found for the first time with a statistical significance of $6.3σ$, and the cross sections at each center-of-mass energy are measured. The ratio of cross sections of $e^+e^-\to K_S^0 K_S^0 ψ(3686)$ relative to $e^+e^-\to K^+ K^- ψ(3686)$ is determined to be $\frac{σ(e^+e^-\to K_S^0 K_S^0 ψ(3686))}{σ(e^+e^-\to K^+ K^- ψ(3686))}=0.45 \pm 0.25$, which is consistent with the prediction based on isospin symmetry. The uncertainty includes both statistical and systematic contributions. Additionally, the $K_S^0ψ(3686)$ invariant mass distribution is found to be consistent with three-body phase space. The significance of a contribution beyond three-body phase space is only $0.8σ$.

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arXiv2025

Partial wave analysis of $ψ(3686)\toΛ\barΣ^0π^0+c.c.$

Based on a sample of $(2712.4\pm14.3)\times10^6\;ψ(3686)$ events collected with the BESIII detector, a partial wave analysis of the decay $ψ(3686)\toΛ\barΣ^0π^0+c.c.$ is performed to investigate $Λ^*$ and $Σ^*$ resonances in the $π^0\barΣ^0$ and $π^0Λ$ invariant mass distributions. Significant contributions are found from the $Λ(1405)$, $Λ(1520)$, $Λ(1600)$, $Λ(1670)$, $Λ(1690)$, $Λ(1800)$, $Λ(1890)$, $Λ(2325)$, $Σ(1385)$, $Σ(1660)$, $Σ(1670)$, $Σ(1750)$, and $Σ(1910)$. The masses, widths, and production branching fractions for each component are determined. In addition, the branching fraction of $ψ(3686)\toΛ\barΣ^0π^0+c.c.$ is measured to be $(1.544\pm0.013\pm0.069)\times10^{-4}$ for the first time, where the first uncertainty is statistical and the second systematic.

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arXiv2025

Search for $Λ$-$\barΛ $ oscillation in $J/ψ\rightarrowΛ\barΛ$ decay

Using $(10087\pm44)\times 10^{6}$ $J/ψ$ decays collected by the BESIII detector at the BEPCII collider, we search for baryon number violation via $Λ-\barΛ$ oscillation in the decay $J/ψ\to Λ\barΛ$. No evidence for $Λ-\barΛ$ oscillation is observed. The upper limit on the time-integrated probability of $Λ-\barΛ$ oscillation is estimated to be $1.4\times 10^{-6}$, corresponding to an oscillation parameter less than $2.1\times 10^{-18}~\mathrm{GeV}$ at $90\%$ confidence level.

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