arXiv subjects

P. Adlarson

Publications and source records attributed to P. Adlarson.

At least 307 records · Page 17Linked to original sources

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.

hep-ex↗

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

Observation of the decay $B^0_{s}\to K^0 p \bar{p}$ and measurement of the $B^0_{(s)} \to K^0 p \bar{p}$ branching fractions

A study of the charmless baryonic decays $B^0_{(s)} \to K^0 p \bar{p}$ is presented, where $B^0_{(s)}$ denotes either a $B^0$ or a $B^0_s$ meson. The analysis is based on proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and $13~\mathrm{Tev}$, corresponding to an integrated luminosity of $9~\mathrm{fb}^{-1}$. The decay $B^0_s \to K^0 p \bar{p}$ is observed for the first time, with a measured branching fraction of $(9.14 \pm 1.69 \pm 0.90 \pm 0.33 \pm 0.20) \times 10^{-7}$ and a significance of $5.6σ$. The uncertainties respectively account for statistical and systematic contributions, the precision of the branching fraction of the normalisation channel $B^0 \to K^0 π^{+} π^{-}$ and the fragmentation fraction ratio ${f_s}/{f_d}$. The branching fraction determined for $B^0 \to K^0 p \bar{p}$ is $(2.82 \pm 0.08 \pm 0.12 \pm 0.10) \times 10^{-6}$, which is the most precise measurement to date.

hep-ex↗

arXiv2025

Evidence for $B^-\rightarrow D^{**0}τ^-\overline{ν_τ}$ decays

The first evidence for the decay $B^-\rightarrow D^{**0}τ^-\overline{ν_τ}$ is obtained using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb$^{-1}$ , at centre-of-mass energies of 7, 8 and 13 Tev. Here, the $D^{**0}$ meson represents any of the three excited charm mesons $D_{1}(2420)^{0}$, $D_{2}^{*}(2460)^{0}$, and $D_{1}^{'}(2400)^{0}$. The $B^-\rightarrow D^{**0}τ^-\overline{ν_τ}$ signal is measured with a significance of 3.5 $σ$, including systematic uncertainties. The combined branching fraction $BR(B^-\rightarrow D^{**0}_{1,2}τ^-\overline{ν_τ})\times BR(D^{**0}_{1,2}\rightarrow D^{*+}π^-)$, where $D^{**0}_{1,2}$ denotes both $D_{1}(2420)^{0}$ and $D_{2}^{*}(2460)^{0}$ contributions, is measured to be $(0.051\pm0.013(stat)\pm 0.006(syst)\pm 0.009(\rm{ext}) )\%$, where the last uncertainty reflects that of the branching fraction of the normalisation channel $B^-\rightarrow D^{**0}_{1,2}D_s^{(*)-}$. The ratio between the tauonic and muonic semileptonic $B$ decays, with the latter taken from world average values, is also determined and found to be ${\cal R}(D^{**0}_{1,2})=0.13\pm0.03(stat)\pm0.01(syst)\pm0.02\,(\rm{ext})$.

hep-ex↗

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

Measurement of $CP$ asymmetry in $B_s^0 \to D_s^{\mp} K^{\pm}$ decays

A measurement of the $CP$-violating parameters in $B_s^0 \to D_s^{\mp} K^{\pm}$ decays is reported, based on the analysis of proton-proton collision data collected by the LHCb experiment corresponding to an integrated luminosity of $6\,\mathrm{fb}^{-1}$ at a centre-of-mass energy of $13 \,\mathrm{TeV}$. The measured parameters are obtained with a decay-time dependent analysis yielding $C_f = 0.791 \pm 0.061 \pm 0.022$, $A_f^{ΔΓ} = -0.051 \pm 0.134 \pm 0.058$, $A_{\overline{f}}^{ΔΓ} = -0.303 \pm 0.125 \pm 0.055$, $S_f = -0.571 \pm 0.084 \pm 0.023$ and $S_{\overline{f}} = -0.503 \pm 0.084 \pm 0.025$, where the first uncertainty is statistical and the second systematic. This corresponds to $CP$ violation in the interference between mixing and decay of about $8.6\,σ$. Together with the value of the Bs mixing phase $-2β_s$, these parameters are used to obtain a measurement of the CKM angle $γ$ equal to $ (74\pm12)^\circ$ modulo $180^{\circ}$, where the uncertainty contains both statistical and systematic contributions. This result is combined with the previous LHCb measurement in this channel using $3\,\mathrm{fb}^{-1}$ resulting in a determination of $γ= (81^{+12}_{-11})^\circ$.

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↗

arXiv2025

Improved measurement of absolute branching fraction of the inclusive decay $Λ_{c}^{+} \to K_{S}^{0} X$

By analyzing $4.5$ fb$^{-1}$ of $e^{+}e^{-}$ collision data accumulated with the BESIII detector at center-of-mass energies ranging from $4599.53$ MeV to $4698.82$ MeV, we report the measurement of the absolute branching fraction (BF) of the inclusive decay $Λ_{c}^{+} \to K_{S}^{0} X$ using the double-tag technique. The result is $\mathcal{B}(Λ_{c}^{+} \to K_{S}^{0} X)=(10.9\pm0.2\pm0.1)\%$, where the first uncertainty is statistical and the second is systematic. This result indicates that there are still undiscovered decay channels containing $K_{S}^{0}$ in the final state with a combined BF of $(3.1\pm0.4)\%$. The BF of the inclusive decay $Λ_{c}^{+} \to \overline{K}^{0} / K^{0} X$ is calculated to be $\mathcal{B}(Λ_{c}^{+} \to \overline{K}^{0} / K^{0} X)=(21.8 \pm0.4 \pm0.2 \pm1.1)\%$, where the third uncertainty accounts for a possible difference between $\mathcal{B}(Λ_{c}^{+} \to K_{S}^{0} X)$ and $\mathcal{B}(Λ_{c}^{+} \to K_{L}^{0} X)$. The result is in agreement with the prediction of the statistical isospin model.

hep-ex↗

arXiv2025

Search for charge-parity violation in semileptonically tagged $D^{0} \to K^{+} π^{-}$ decays

An analysis of the flavour oscillations of the charmed neutral meson is presented. The ratio of $D^{0} \to K^{+} π^{-}$ and $D^{0} \to K^{-} π^{+}$ decay rates is measured as a function of the decay time of the $D^{0}$ meson and compared with the charge-conjugated system to search for charge-parity violation. The meson flavour at production is double-tagged by the charges of the muon and pion in the preceding $\overline{B} \to D^{*}(2010)^{+} μ^{-} X$ and ${{D^{*}(2010)^{+}} \to D^{0}π^{+}}$ decays, respectively. These decays are selected from proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of ${13\,\text{TeV}}$ and corresponding to an integrated luminosity of ${5.4\,\text{fb}^{-1}}$. The flavour oscillation parameters, relating to the differences in mass and width of the mass eigenstates, are found to be ${y^\prime=(5.8\pm1.6)\times10^{-3}}$ and ${(x^\prime)^2=(0.0\pm1.2)\times10^{-4}}$. No evidence for charge-parity violation is seen either in the flavour oscillations or in the decay, where the direct charge-parity asymmetry is measured to be ${A_{D}=(2.3\pm1.7)\,{\%}}$.

hep-ex↗

arXiv2025

Measurement of the $η$ transition form factor through $η' \rightarrow π^+π^-η$ decay

Based on a sample of $(1.0087\pm0.0044)\times10^{10}$ $J/ψ$ events collected at BESIII, the transition form factor of the $η$ meson is extracted by analyzing $J/ψ\toγη',~η'\toπ^+π^-η,~η\toγl^+l^-$ ($l$=$e$, $μ$) events. The measured slope of the transition form factor is $Λ^{-2}=1.645\pm0.093_{\rm stat.}\pm {0.024_{\rm sys.}}$ (GeV/$c^2$)$^{-2}$ for the di-electron channel and $Λ^{-2}=1.645\pm0.343_{\rm stat.}\pm0.017_{\rm sys.}$ (GeV/$c^2$)$^{-2}$ for the di-muon channel. The branching fractions for $η\rightarrowγe^+e^-$ and $η\rightarrowγμ^+μ^-$ are measured to be $\mathcal{B}(η\toγe^+e^-)=(6.79\pm0.04_{\rm stat.}\pm0.36_{\rm sys.})\times 10^{-3}$ and $\mathcal{B}(η\toγμ^+μ^-)=(2.97\pm0.11_{\rm stat.}\pm0.07_{\rm sys.})\times 10^{-4}$. By combining with the results based on the $J/ψ\toγη,~η\toγe^+e^-$ events from the previous BESIII measurement, we determine $Λ^{-2}=1.707\pm0.076_{\rm stat.}\pm0.029_{\rm sys.}$ (GeV/$c^2$)$^{-2}$ and $\mathcal{B}(η\toγe^+e^-)=(6.93\pm0.28_{\rm tot.})\times 10^{-3}$. In addition, we search for the dark photon ($A'$) using the combined events. No significant signal is observed, and the upper limits on $\mathcal{B}(η\toγA',~A'\to e^+e^-)$ are set at 90\% confidence level for different $A'$ mass hypotheses.

hep-ex↗

arXiv2025

First observation of quantum correlations in $e^+e^-\to XD\bar{D}$ and $C$-even constrained $D\bar{D}$ pairs

The study of meson pairs produced with quantum correlations gives direct access to parameters that are challenging to measure in other systems. In this Letter, the existence of quantum correlations due to charge-conjugation symmetry $C$ are demonstrated in $D\bar{D}$ pairs produced through the processes $e^+e^-\to D\bar{D}$, $e^+e^- \to D^{*}\bar{D}$, and $e^+e^- \to D^{*} \bar{D}^*$, where the lack of charge superscripts refers to an admixture of neutral-charm-meson particle and antiparticle states, using $7.13 \text{ fb}^{-1}$ of $e^+e^-$ collision data collected by the BESIII experiment between center-of-mass energies of $4.13-4.23 \text{ GeV}$. Processes with either $C$-even or $C$-odd constraints are identified and separated. A procedure is presented that harnesses the entangled production process to enable measurements of $D^0$-meson hadronic parameters. This study provides the first confirmation of quantum correlations in $e^+e^-\to X D\bar{D}$ processes and the first observation of a $C$-even constrained $D\bar{D}$ system. The procedure is applied to measure $δ^{D}_{Kπ}$, the strong phase between the $D^0\to K^-π^+$ and $\bar{D}^0\to K^-π^+$ decay amplitudes, which results in the determination of $δ^{D}_{Kπ}=\left(192.8^{+11.0 + 1.9}_{-12.4 -2.4}\right)^\circ$. The potential for measurements of other hadronic decay parameters and charm mixing with these and future datasets is also discussed.

hep-ex↗

arXiv2025

A novel measurement of the strong-phase difference between $D^0\to K^-π^+$ and $\bar{D}^0\to K^-π^+$ decays using $C$-even and $C$-odd quantum-correlated $D\bar{D}$ pairs

A novel measurement technique of strong-phase differences between the decay amplitudes of $D^0$ and $\bar{D}^0$ mesons is introduced which exploits quantum-correlated $D\bar{D}$ pairs produced by $e^+e^-$ collisions at energies above the $ψ(3770)$ production threshold, where $D\bar{D}$ pairs are produced in both even and odd eigenstates of the charge-conjugation symmetry. Employing this technique, the first determination of a $D^0$-$\bar{D^0}$ relative strong phase is reported with such data samples. The strong-phase difference between $D^0\to K^-π^+$ and $\bar{D}^0\to K^-π^+$ decays, $δ^{D}_{Kπ}$, is measured to be $δ^{D}_{Kπ}=\left(192.8^{+11.0 + 1.9}_{-12.4 -2.4}\right)^\circ$, using a dataset corresponding to an integrated luminosity of 7.13 $\text{fb}^{-1}$ collected at center-of-mass energies between $4.13-4.23 \text{ GeV}$ by the BESIII experiment.

hep-ex↗

arXiv2025

Search for $η_{1}(1855)$ in $χ_{cJ}\toηηη^{\prime}$ decays

Based on a sample of $2.7\times10^{9}$ $ψ(3686)$ events collected by the BESIII detector operating at the BEPCII collider, an analysis of the decay $ψ(3686)\toγχ_{cJ}, χ_{cJ}\toηηη^{\prime}$ is performed. The decay modes $χ_{c1}$ and $χ_{c2}\toηηη^{\prime}$ are observed for the first time, and their corresponding branching fractions are determined to be $\mathcal{B}(χ_{c1}\toηηη^{\prime}) = (1.40\, \pm 0.13\, (\text{stat.}) \pm 0.09\, (\text{sys.})) \times 10^{-4}$ and $\mathcal{B}(χ_{c2}\toηηη^{\prime}) = (4.18\, \pm 0.84\, (\text{stat.}) \pm 0.48\, (\text{sys.})) \times 10^{-5}$. An upper limit on the branching fraction of $χ_{c0}\toηηη^{\prime}$ is set as $2.59 \times 10^{-5}$ at 90\% confidence level (CL). A partial wave analysis (PWA) of the decay $χ_{c1}\toηηη^{\prime}$ is performed to search for the $1^{-+}$ exotic state $η_1(1855)$. The PWA result indicates that the structure in the $ηη^{\prime}$ mass spectrum is mainly attributed to the $f_0(1500)$, while in the $ηη$ mass spectrum, it is primarily the $0^{++}$ phase space. The upper limit of $\mathcal{B}(χ_{c1}\toη_{1}(1855)η) \cdot \mathcal{B}(η_{1}(1855)\toηη^{\prime})< 9.79 \times 10^{-5}$ is set based on the PWA at 90\% CL.

hep-ex↗

arXiv2025

Study of $\itΛ_{\it{b}}^\rm{0}$ and $\itΞ_{\it{b}}^\rm{0}$ decays to $\itΛ h^+h^{'-}$ and evidence for $CP$ violation in $\itΛ_{\it{b}}^\rm{0}\to\itΛ K^+K^-$ decays

A study of $\itΛ_{\it{b}}^\rm{0}$ and $\itΞ_{\it{b}}^\rm{0}$ decays to $\itΛ h^{+} h^{\prime -}$ $(h^{(\prime)}=π, K)$ is performed using $pp$ collision data collected by the LHCb experiment during LHC Runs 1$-$2, corresponding to an integrated luminosity of $9~\rm{fb}^{-1}$. The branching fractions for these decays are measured using the $\itΛ_{\it{b}}^\rm{0}\to\itΛ_{\it{c}}^+(\to\itΛπ^+)π^-$ decay as control channel. The decays $\itΛ_{\it{b}}^\rm{0}\to\itΛπ^+π^-$ and $\itΞ_{\it{b}}^\rm{0}\to\itΛK^-π^+$ are observed for the first time. For decay modes with sufficient signal yields, $CP$ asymmetries are measured in the full and localized regions of the final-state phase space. Evidence is found for $CP$ violation in the $\itΛ_{\it{b}}^\rm{0}\to\itΛK^+K^-$ decay, interpreted as originating primarily from an asymmetric $\itΛ_{\it{b}}^\rm{0} \to \it{N}^{*+} \it{K}^-$ decay amplitude. The measured $CP$ asymmetries for the other decays are compatible with zero.

hep-ex↗

arXiv2025

Study of $D_{s1}(2460)^{+}\to D_{s}^{+}π^{+}π^{-}$ in $B\to {\bar{D}}^{(*)}D_{s}^{+}π^{+}π^{-}$ decays

An amplitude analysis of the $D_{s1}(2460)^+\to D_{s}^{+}π^{+}π^{-}$ transition is performed simultaneously in $B^{0}\to D^{-}D_{s}^{+}π^{+}π^{-}$, $B^{+}\to{\bar{D}}^{0} D_{s}^{+}π^{+}π^{-}$, and $B^{0}\to D^{*-}D_{s}^{+}π^{+}π^{-}$ decays. The study is based on a data sample of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of $\sqrt{s}=7,8,$ and $13\,$TeV, corresponding to a total integrated luminosity of $9\,\rm{fb}^{-1}$. A clear double-peak structure is observed in the $m(π^{+}π^{-})$ spectrum of the $D_{s1}(2460)^{+}\to D_{s}^{+}π^{+}π^{-}$ decay. The data can be described either with a model including $f_0(500)$, $f_0(980)$ and $f_2(1270)$ resonances, in which the contributions of $f_0(980)$ and $f_2(1270)$ are unexpectedly large, or with a model including $f_0(500)$, a doubly charged open-charm tetraquark state $T_{c\bar{s}}^{++}$ and its isospin partner $T_{c\bar{s}}^{0}$. If the former is considered implausible, the $T_{c\bar{s}}$ states are observed with high significance, and the data are consistent with isospin symmetry. When imposing isospin constraints between the two $T_{c\bar{s}}$ states, their mass and width are determined to be $2327\pm13\pm13\,$MeV and $96\pm16\,^{+170}_{-23}\,$MeV, respectively, where the first uncertainty is statistical and the second is systematic. The mass is slightly below the $DK$ threshold, and a spin-parity of $0^+$ is favoured with high significance.

hep-ex↗

arXiv2025

Search for $e^+e^-\to K_S^0 K_S^0 h_c$

Using $e^+e^-$ collision data at 13 center-of-mass energies ranging from 4.600 to 4.950 GeV collected with the BESIII detector, we search for the unmeasured $e^+e^-\to K_S^0 K_S^0 h_c$ process . No significant signal is observed, and the upper limits of the Born cross sections at each center-of-mass energy are presented.

hep-ex↗

arXiv2025

Search for resonance-enhanced $CP$ and angular asymmetries in the $Λ^+_{c}\to pμ^+μ^-$ decay at LHCb

The first measurement of the $CP$ asymmetry of the decay rate ($A_{CP}$) and the $CP$ average ($ΣA_{\text{FB}}$) and $CP$ asymmetry ($ΔA_{\text{FB}}$) of the forward-backward asymmetry in the muon system of $\mathitΛ^+_c\to pμ^+μ^-$ decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13$\text{ TeV}$, which corresponds to an integrated luminosity of 5.4$\text{ fb}^{-1}$. The asymmetries are measured in two regions of dimuon mass near the $ϕ$-meson mass peak. The dimuon-mass integrated results are \begin{align*} A_{CP} &= (-1.1 \pm 4.0 \pm 0.5)\%,\\ ΣA_{\text{FB}} &= (\phantom{-}3.9 \pm 4.0 \pm 0.6)\%,\\ ΔA_{\text{FB}} &= (\phantom{-}3.1 \pm 4.0 \pm 0.4)\%, \end{align*} where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of $CP$ symmetry and the Standard Model expectations.

hep-ex↗