arXiv subjects

P. Adlarson

Publications and source records attributed to P. Adlarson.

At least 451 records · Page 25Linked to original sources

arXiv2024

Measurement of the mass difference and relative production rate of the $Ω^-_b$ and $Ξ^-_b$ baryons

The mass difference between the $Ω^-_b$ and $Ξ^-_b$ baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of $9 \, \text{fb}^{-1}$, and is found to be \begin{equation} m(Ω^-_b)- m(Ξ^-_b) = 248.54 \pm 0.51 \text{(stat)} \pm 0.38 \text{(syst)} \, \text{MeV}/c^2. \end{equation} The mass of the $Ω^-_b$ baryon is measured to be \begin{equation} m(Ω^-_b)= 6045.9 \pm 0.5 \text{(stat)} \pm 0.6 \text{(syst)} \, \text{MeV}/c^2. \end{equation} This is the most precise determination of the $Ω^-_b$ mass to date. In addition, the production rate of $Ω^-_b$ baryons relative to that of $Ξ^-_b$ baryons is measured for the first time in $pp$ collisions, using an LHCb dataset collected at a center-of-mass energy of $13 \, \text{TeV}$ and corresponding to an integrated luminosity of $6\,\text{fb}^{-1}$. Reconstructing beauty baryons in the kinematic region $2 < η< 6$ and $p_T < 20\,\text{GeV}/c$ with their decays to a $J/ψ$ meson and a hyperon, the ratio \begin{equation} \frac{f_{Ω^-_b}}{f_{Ξ^-_b}}\times\frac{\mathcal{B}(Ω^-_b \to J/ψΩ^-)}{\mathcal{B}(Ξ^-_b \to J/ψΞ^-)} = 0.120 \pm 0.008 \text{(stat)} \pm 0.008 \text{(syst)}, \end{equation} is obtained, where $f_{Ω^-_b}$ and $f_{Ξ^-_b}$ are the fragmentation fractions of $b$ quarks into $Ω^-_b$ and $Ξ^-_b$ baryons, respectively, and $\mathcal{B}$ represents the branching fractions of their respective decays.

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arXiv2024

First observation of $Λ_{b}^{0} \rightarrow Σ_c^{()++} D^{()-} K^{-}$ decays

The four decays, $Λ_{b}^{0} \rightarrow Σ_c^{(*)++} D^{(*)-} K^{-}$, are observed for the first time using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of $13\,\rm{TeV}$, corresponding to an integrated luminosity of $6\,\rm{fb}^{-1}$. By considering the $Λ_b^0 \rightarrow Λ_c^{+} \overline{D}^0 K^{-}$ decay as reference channel, the following branching fraction ratios are measured to be $$\frac{\cal{B} (Λ_{b}^{0} \rightarrow Σ_{c}^{++} \rm{D}^{-} {K}^{-})}{\cal{B}(Λ_{b}^{0} \rightarrow Λ_c^{+} \rm \overline{D}^0 {K}^{-})} = {0.282}\pm{0.016}\pm{0.016}\pm{0.005}, \frac{\cal{B}(Λ_{b}^{0} \rightarrow Σ_{c}^{*++} \rm {D}^{-} {K}^{-})}{\cal{B}(Λ_{b}^{0} \rightarrow Σ_c^{++} \rm {D}^{-} {K}^{-})} = {0.460}\pm{0.052}\pm{0.028}, \frac{\cal{B}(Λ_{b}^{0} \rightarrow Σ_{c}^{++} \rm {D}^{*-} {K}^{-})}{\cal{B}(Λ_{b}^{0} \rightarrow Σ_c^{++} \rm {D}^{-} {K}^{-})} = {2.261}\pm{0.202}\pm{0.129}\pm{0.046}, \frac{\cal{B}(Λ_{b}^{0} \rightarrow Σ_{c}^{*++} \rm D^{*-} K^{-})}{\cal{B}(Λ_{b}^{0} \rightarrow Σ_c^{++} \rm D^{-} K^{-})} = {0.896}\pm{0.137}\pm{0.066}\pm{0.018},$$ where the first uncertainties are statistical, the second are systematic, and the third are due to uncertainties in the branching fractions of intermediate particle decays. These initial observations mark the beginning of pentaquark searches in these modes, with more data set to become available following the LHCb upgrade.

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arXiv2024

Precise Measurement of Born Cross Sections for $e^+e^-\to D\bar{D}$ at $\sqrt{s} = 3.80-4.95$ GeV

Using data samples collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 3.80 to 4.95 GeV, corresponding to an integrated luminosity of 20 fb$^{-1}$, a measurement of Born cross sections for the $e^+e^-\to D^{0}\bar{D}^{0}$ and $D^{+}D^{-}$ processes is presented with unprecedented precision. Many clear peaks in the line shape of $e^+e^-\to D^{0}\bar{D}^{0}$ and $D^{+}D^{-}$ around the mass range of $G(3900)$, $ψ(4040)$, $ψ(4160)$, $Y(4260)$, and $ψ(4415)$, etc., are foreseen. These results offer crucial experimental insights into the nature of hadron production in the open-charm region.

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arXiv2024

Search for the rare decay $J/ψ\to γD^0+c.c.$ at BESIII

Using $(10087\pm44)\times10^6J/ψ$ events collected with the BESIII detector, we search for the rare decay $J/ψ\to γD^0+c.c.$ for the first time. No obvious signal is observed and the upper limit on the branching fraction is determined to be ${\cal B}(J/ψ\to γD^{0}+c.c.)< 9.1 \times 10^{-8}$ at 90\% confidence level.

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arXiv2024

Observation of new baryons in the $Ξ_b^-π^+π^-$ and $Ξ_b^0π^+π^-$ systems

The first observation and study of two new baryonic structures in the final state $Ξ_b^0π^+π^-$ and the confirmation of the $Ξ_b(6100)^-$ state in the $Ξ_b^-π^+π^-$ decay mode are reported using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9$\mathrm{fb}^{-1}$. In addition, the properties of the known $Ξ_b^{*0}$, $Ξ_b^{'-}$ and $Ξ_b^{*-}$ resonances are measured with improved precision. The new decay mode of the $Ξ_b^0$ baryon to the $Ξ_c^+π^-π^+π^-$ final state is observed and exploited for the first time in these measurements.

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arXiv2024

Measurements of $K_S^0$-$K_L^0$ asymmetries in the decays $Λ_c^+ \to pK_{L,S}^0$, $pK_{L,S}^0π^+π^-$ and $pK_{L,S}^0π^0$

Using $e^+e^-$ annihilation data sets corresponding to an integrated luminosity of 4.5 $\text{fb}^{-1}$, collected with the BESIII detector at center-of-mass energies between 4.600 and 4.699 GeV, we report the first measurements of the absolute branching fractions $\mathcal{B}(Λ_c^+\to pK_{L}^{0})=(1.67 \pm 0.06 \pm 0. 04)\%$, $\mathcal{B}(Λ_c^+\to pK_{L}^{0}π^+π^-)=(1.69 \pm 0.10 \pm 0.05)\%$, and $\mathcal{B}(Λ_c^+\to pK_{L}^{0}π^0)=(2.02 \pm 0.13 \pm 0.05)\%$, where the first uncertainties are statistical and the second systematic. Combining with the known branching fractions of $Λ_c^+ \to pK_{S}^{0}$, $Λ_c^+ \to pK_{S}^{0}π^+π^-$, and $Λ_c^+ \to pK_{S}^{0}π^0$, we present the first measurements of the $K_{S}^{0}$-$K_{L}^{0}$ asymmetries $R(Λ_c^+, K_{S,L}^0X) = \frac{\mathcal{B}(Λ_c^+ \to K_{S}^{0} X) - \mathcal{B}(Λ_c^+ \to K_{L}^{0} X)}{\mathcal{B}(Λ_c^+ \to K_{S}^{0} X) + \mathcal{B}(Λ_c^+ \to K_{L}^{0} X)}$ in charmed baryon decays: $R(Λ_c^+, pK_{S,L}^0) = -0.025 \pm 0.031$, $R(Λ_c^+, pK_{S,L}^0π^+π^-) = -0.027 \pm 0.048$, and $R(Λ_c^+, pK_{S,L}^0π^0) =-0.015 \pm 0.046$. No significant asymmetries within the uncertainties are observed.

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arXiv2024

Search for $η_c(2S)\toωω$ and $ωϕ$ decays and measurements of $χ_{cJ}\toωω$ and $ωϕ$ in $ψ(2S)$ radiative processes

Using $(2712\pm 14)$ $\times$ 10$^{6}$ $ψ(2S)$ events collected with the BESIII detector at the BEPCII collider, we search for the decays $η_{c}(2S)\toωω$ and $η_{c}(2S)\toωϕ$ via the process $ψ(2S)\toγη_{c}(2S)$. Evidence of $η_{c}(2S)\toωω$ is found with a statistical significance of $3.2σ$. The branching fraction is measured to be $\mathcal{B}(η_{c}(2S)\toωω)=(5.65\pm3.77(\rm stat.)\pm5.32(\rm syst.))\times10^{-4}$. No statistically significant signal is observed for the decay $η_{c}(2S)\toωϕ$. The upper limit of the branching fraction at the 90\% confidence level is determined to be $\mathcal{B}(ψ(2S)\toγη_{c}(2S),η_{c}(2S)\toωϕ)<2.24\times 10^{-7}$. We also update the branching fractions of $χ_{cJ}\to ωω$ and $χ_{cJ}\toωϕ$ decays via the $ψ(2S)\toγχ_{cJ}$ transition. The branching fractions are determined to be $\mathcal{B}(χ_{c0}\toωω)=(10.63\pm0.11\pm0.46)\times 10^{-4}$, $\mathcal{B}(χ_{c1}\toωω)=(6.39\pm0.07\pm0.29)\times 10^{-4}$, $\mathcal{B}(χ_{c2}\toωω)=(8.50\pm0.08\pm0.38)\times 10^{-4}$, $\mathcal{B}(χ_{c0}\toωϕ)=(1.18\pm0.03\pm0.05)\times 10^{-4}$, $\mathcal{B}(χ_{c1}\toωϕ)=(2.03\pm0.15\pm0.12)\times 10^{-5}$, and $\mathcal{B}(χ_{c2}\toωϕ)=(9.37\pm1.07\pm0.59)\times 10^{-6}$, where the first uncertainties are statistical and the second are systematic.

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arXiv2024

Search for $e^{+}e^{-}\toη'ψ(2S)$ at center-of-mass energies from 4.66 to 4.95 GeV

Using data samples with an integrated luminosity of $4.67~\mathrm{fb}^{-1}$ collected by the BESIII detector operating at the BEPCII collider, we search for the process $e^+e^- \rightarrow η' ψ(2S)$ at center-of-mass energies from $4.66$ to $4.95~\mathrm{GeV}$. No significant signal is observed, and upper limits for the Born cross sections $σ^B(e^+e^-\rightarrowη'ψ(2S))$ at the 90\% confidence level are determined.

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arXiv2024

Measurement of the Branching Fraction of \boldmath{$ψ(2S) \to γπ^0$}

Based on $(2712.4\pm14.1)\times10^{6}~ψ(2S)$ events, 7.9 fb$^{-1}$ $ψ(3773)$ data, and 0.8 fb$^{-1}$ off-resonance data samples collected with the BESIII detector, we measure the branching fraction of $ψ(2S)\rightarrowγπ^{0}$ and $e^{+}e^{-}\rightarrowγπ^{0}$ form factor at momentum transfers $Q^{2}\sim13$ GeV$^{2}$. The $e^{+}e^{-}\rightarrowγπ^{0}$ cross section is fitted with considering the interference between the $ψ(2S)$ and continuum amplitudes and two solutions are found, ${\cal B}=3.74\times10^{-7}$ with $ϕ=3.93$ rad and ${\cal B}=7.87\times10^{-7}$ with $ϕ=2.08$ rad. Here, ${\cal B}$ is the branching fraction of $ψ(2S)\rightarrowγπ^{0}$ and $ϕ$ is the relative phase angle between the $ψ(2S)$ and continuum amplitudes. Due to insufficient off-resonance data, the branching fraction ${\cal B}(ψ(2S)\rightarrowγπ^{0})$ is determined to be in the range $[2.7, 9.7]\times10^{-7}$ within one standard deviation of the contour region.

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arXiv2024

Analysis of the dynamics of the decay $D^{+}\to K_{S}^{0} π^{0} e^{+}ν_{e}$

The branching fraction of $D^+\to K_{S}^{0} π^{0}e^+ν_e$ is measured for the first time using $7.93~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data collected at the center-of-mass energy $\sqrt{s}=3.773$~GeV with the BESIII detector operating at the BEPCII collider, and is determined to be ${\mathcal B}$($D^+\to K_S^0π^0e^+ν_e$) = $(0.881~\pm~0.017_{\rm stat.}~\pm~0.016_{\rm syst.})$\%. Based on an analysis of the $D^+\to K_S^0π^0e^+ν_e$ decay dynamics, we observe the $S\text{-}{\rm wave}$ and $P$-wave components with fractions of $f_{S\text{-}{\rm wave}}$ = $(6.13~\pm~0.27_{\rm stat.}~\pm ~0.30_{\rm syst.})\%$ and $f_{\bar K^{*}(892)^0}$ = $(93.88~\pm~0.27_{\rm stat.}~\pm~0.29_{\rm syst.})$\%, respectively. From these results, we obtain the branching fractions ${\mathcal B}$($D^+\to (K_S^0π^0)_{S\text{-}{\rm wave}}~e^+ν_e$) = $(5.41~\pm~0.35_{\rm stat.}~\pm~0.37_{\rm syst.})\times10^{-4}$ and ${\mathcal B}$($D^+\to \bar K^{*}(892)^0e^+ν_e$) = $(4.97~\pm~0.11_{\rm stat.}~\pm~0.12_{\rm syst.})$\%. In addition, the hadronic form-factor ratios of $D^{+} \to \bar {K}^{*}(892)^0e^+ν_e$ at $q^2=0$, assuming a single-pole dominance parameterization, are determined to be $r_V=\frac{V(0)}{A_1(0)}= 1.43~\pm~0.07_{\rm stat.}~\pm~0.03_{\rm syst.}$ and $r_2=\frac{A_2(0)}{A_1(0)}=0.72~\pm~0.06_{\rm stat.}~\pm~0.02_{\rm syst.}$.

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arXiv2024

Observation of $η_{c}(2S) \to K^{+}K^{-}η$

By analyzing $(27.12 \pm 0.14)\times10^{8}$ $ψ(3686)$ events accumulated with the BESIII detector, the decay $η_{c}(2S) \to K^{+} K^{-} η$ is observed for the first time with a significance of $6.2σ$ after considering systematic uncertainties. The product of the branching fractions of $ψ(3686) \to γη_{c}(2S)$ and $η_{c}(2S) \to K^{+} K^{-} η$ is measured to be $\mathcal{B}(ψ(3686) \toγη_{c}(2S))\times \mathcal{B}(η_{c}(2S)\to K^{+} K^{-}η)=(2.39 \pm 0.32 \pm 0.34) \times 10^{-6}$, where the first uncertainty is statistical, and the second one is systematic. The branching fraction of $η_{c}(2S)\to K^{+} K^{-}η$ is determined to be $\mathcal{B}(η_{c}(2S)\to K^{+} K^{-}η) = (3.42 \pm 0.46 \pm 0.48 \pm 2.44) \times 10^{-3}$, where the third uncertainty is due to the branching fraction of $ψ(3686) \to γη_{c}(2S)$. Using a recent BESIII measurement of $\mathcal{B} (η_{c}(2S) \to K^{+} K^{-}π^{0})$, we also determine the ratio between the branching fractions of $η_{c}(2S) \to K^{+} K^{-}η$ and $η_{c}(2S) \to K^{+} K^{-}π^{0}$ to be $1.49 \pm 0.22 \pm 0.25$, which is consistent with the previous result of BaBar at a comparable precision level.

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arXiv2024

Search for di-photon decays of an axion-like particle in radiative $J/ψ$ decays

We search for the di-photon decay of a light pseudoscalar axion-like particle, $a$, in radiative $J/ψ$ decays, using 10 billion $J/ψ$ events collected with the BESIII detector. We find no evidence of a signal and set upper limits at the $95\%$ confidence level on the product branching fraction $\mathcal{B}(J/ψ\to γa) \times \mathcal{B}(a \to γγ)$ and the axion-like particle photon coupling constant $g_{a γγ}$ in the ranges of $(3.7-48.5) \times 10^{-8}$ and $(2.2 -101.8)\times 10^{-4}$ GeV$^{-1}$, respectively, for $0.18 \le m_a \le 2.85$ GeV/$c^2$. These are the most stringent limits to date in this mass region.

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arXiv2024

Search for prompt production of pentaquarks in charm hadron final states

A search for hidden-charm pentaquark states decaying to a range of $Σ_{c}\bar{D}$ and $Λ_{c}\bar{D}$ final states, as well as doubly-charmed pentaquark states to $Σ_{c}D$ and $Λ_{c}^{+}D$, is made using samples of proton-proton collision data corresponding to an integrated luminosity of $5.7fb^{-1}$ recorded by the LHCb detector at $\sqrt{s} = 13Te\kern -0.1em V$. Since no significant signals are found, upper limits are set on the pentaquark yields relative to that of the $Λ_{c}^{+}$ baryon in the $Λ_{c}^{+}\to pK^{-}π^{+}$ decay mode. The known pentaquark states are also investigated, and their signal yields are found to be consistent with zero in all cases.

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arXiv2024

Measurement of the $\boldsymbol{e^{+}e^{-}\to K^+K^-ψ(2S)}$ Cross Section at Center-of-Mass Energies from 4.699 to 4.951 GeV and Search for $\boldsymbol{Z_{cs}^{\pm}}$ in the $\boldsymbol{Z_{cs}^\pm\to K^\pmψ(2S)}$ Decay

We perform the first investigation of the process $e^{+}e^{-}\to K^+K^-ψ(2S)$ and report its Born cross sections over a range of center-of-mass energies from 4.699 to 4.951~GeV. The measurements are carried out using several partial reconstruction techniques using data samples collected by the BESIII detector with a total integrated luminosity of 2.5~fb$^{-1}$. We search for new tetraquark candidates $Z_{cs}^\pm$ in the decays $Z_{cs}^\pm\to K^\pmψ(2S)$. No significant $Z_{cs}^\pm$ signals are observed.

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arXiv2024

Measurement of the cross sections of $e^+e^-\to K^{-}\barΞ^{+}Λ/Σ^{0}$ at center-of-mass energies between 3.510 and 4.914 GeV

Using $e^+e^-$ collision data collected with the BESIII detector at the BEPCII collider at center-of-mass energies between 3.510 and 4.914GeV, corresponding to an integrated luminosity of 25 fb$^{-1}$, we measure the Born cross sections for the process $e^+e^-\to K^-\barΞ^+Λ/Σ^{0}$ at thirty-five energy points with a partial-reconstruction strategy. By fitting the dressed cross sections of $e^+e^-\to K^-\barΞ^+Λ/Σ^{0}$, evidence for $ψ(4160) \to K^{-}\barΞ^{+}Λ$ is found for the first time with a significance of 4.4$σ$, including systematic uncertainties. No evidence for other possible resonances is found. In addition, the products of electronic partial width and branching fraction for all assumed resonances decaying into $K^{-}\barΞ^{+}Λ/Σ^{0}$ are determined.

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arXiv2024

Improved measurement of the branching fraction of $h_{c}\rightarrowγη^\prime/η$ and search for $h_{c}\rightarrowγπ^0$

The processes $h_c\toγP(P = η^\prime,~η,~π^0)$ are studied with a sample of $(27.12\pm0.14)\times10^{8}$ $ψ(3686)$ events collected by the BESIII detector at the BEPCII collider. The decay $h_{c}\rightarrowγη$ is observed for the first time with the significance of $9.0\,σ$, and the branching fraction is determined to be $(3.77\pm0.55\pm0.13\pm0.26)\times10^{-4}$, while $\mathscr{B}(h_{c}\rightarrowγη^\prime)$ is measured to be $(1.40\pm0.11\pm0.04\pm0.10)\times10^{-3}$, where the first uncertainties are statistical, the second systematic, and the third from the branching fraction of $ψ(3686)\rightarrowπ^{0}h_c$. The combination of these results allows for a precise determination of $R_{h_c}=\frac{\mathscr{B}(h_c\rightarrowγη)}{\mathscr{B}(h_c\rightarrowγη^\prime)}$, which is calculated to be $(27.0\pm4.4\pm1.0)\%$. The results are valuable for gaining a deeper understanding of $η-η^\prime$ mixing, and its manifestation within quantum chromodynamics. No significant signal is found for the decay $h_c\rightarrowγπ^{0}$, and an upper limit is placed on its branching fraction of $\mathscr{B}(h_c\rightarrowγπ^{0})<5.0\times10^{-5}$, at the 90$\%$ confidence level.

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arXiv2024

Search for $η_{c}(2S)\to K^+ K^- η^{\prime}$ decay

Using $(2.712\pm0.014)\times10^{9}$ $ψ(3686)$ events collected with the BESIII detector operating at the BEPCII, we find an evidence of the $η_{c}(2S)\to K^+ K^- η^{\prime}$ decay with a statistical significance of 3.1$σ$. Its decay branching fraction is measured to be $(12.24\pm4.60(\mathrm{stat.})\pm2.37(\mathrm{syst.})\pm4.68(\mathrm{extr.}))\times 10^{-4}$, where the first uncertainty is statistical, the second is systematic, and the third uncertainty is from the branching fraction of the $ψ(3686)\toγη_{c}(2S)$ decay. The upper limit on the product branching fraction $B[ψ(3686)\toγη_{c}(2S)] \times$ $B[η_{c}(2S)\to K^+ K^- η^{\prime}]$ is set to be $1.14 \times 10^{-6}$ at $90\%$ confidence level. In addition, the branching fractions of $χ_{c1}\to K^+ K^- η^{\prime}$ and $χ_{c2}\to K^+ K^- η^{\prime}$ are updated to be $(8.47\pm0.09(\mathrm{stat.})\pm0.47(\mathrm{syst.}))\times 10^{-4}$ and $(1.53\pm0.04(\mathrm{stat.})\pm0.08(\mathrm{syst.}))\times 10^{-4}$, respectively. The precision is improved by twofold.

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arXiv2024

Search for the $B_s^0 \rightarrow μ^+μ^-γ$ decay

A search for the fully reconstructed $B_s^0 \rightarrow μ^+μ^-γ$ decay is performed at the LHCb experiment using proton-proton collisions at $\sqrt{s}=13$\,TeV corresponding to an integrated luminosity of $5.4\,\mathrm{fb^{-1}}$. No significant signal is found and upper limits on the branching fraction in intervals of the dimuon mass are set \begin{align} {\cal B}(B_s^0 \rightarrow μ^+μ^-γ) < 4.2\times10^{-8},~&m(μμ)\in[2m_μ,~1.70]\,\mathrm{GeV/c^2} ,\nonumber {\cal B}(B_s^0 \rightarrow μ^+μ^-γ) < 7.7\times10^{-8},~&m(μμ)\in[1.70,~2.88]\,\mathrm{GeV/c^2},\nonumber {\cal B}(B_s^0 \rightarrow μ^+μ^-γ) < 4.2\times10^{-8},~&m(μμ)\in[3.92 ,~m_{B_s^0}]\,\mathrm{GeV/c^2},\nonumber \end{align} at 95\% confidence level. Additionally, upper limits are set on the branching fraction in the $[2m_μ,~1.70]\,\mathrm{GeV/c^2}$ dimuon mass region excluding the contribution from the intermediate $ϕ(1020)$ meson, and in the region combining all dimuon-mass intervals.

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