Searcharxiv⌕ Search

arXiv subjects

P. Adlarson

Publications and source records attributed to P. Adlarson.

At least 577 records · Page 32Linked to original sources
arXiv2023

Observation of a vector charmoniumlike state at 4.7 ${\rm GeV}/c^2$ and search for $Z_{cs}$ in $e^+e^-\to K^+K^-J/ψ$

Using data samples with an integrated luminosity of 5.85~fb$^{-1}$ collected at center-of-mass energies from 4.61 to 4.95 GeV with the BESIII detector operating at the BEPCII storage ring, we measure the cross section for the process $e^+e^-\to K^+K^-J/ψ$. A new resonance with a mass of $M = 4708_{-15}^{+17}\pm21$ MeV/$c^{2}$ and a width of $Γ= 126_{-23}^{+27}\pm30$ MeV is observed in the energy-dependent line shape of the $e^+e^-\to K^+K^-J/ψ$ cross section with a significance over $5σ$. The $K^{+}J/ψ$ system is also investigated to search for charged charmoniumlike states, but no significant $Z_{cs}^+$ states are observed. Upper limits on the Born cross sections for $e^+e^-\to K^{-} Z_{cs}(3985)^{+}/K^{-} Z_{cs}(4000)^{+} + c.c.$ with $Z_{cs}(3985)^{\pm}/Z_{cs}(4000)^{\pm}\to K^{\pm} J/ψ$ are reported at 90\% confidence levels. The ratio of branching fractions $\frac{\mathcal{B}(Z_{cs}(3985)^{+}\to K^+ J/ψ)}{\mathcal{B}(Z_{cs}(3985)^{+}\to (\bar{D}^{0}D_s^{*+} + \bar{D}^{*0}D_s^+))}$ is measured to be less than 0.03 at 90\% confidence level.

hep-ex↗
arXiv2023

Improved measurement of the decays $η' \to π^{+}π^{-}π^{+(0)}π^{-(0)}$ and search for the rare decay $η' \to 4π^{0}$

Using a sample of 10 billion $J/ψ$ events collected with the BESIII detector, the decays $η' \to π^{+}π^{-}π^{+}π^{-}$, $η' \to π^{+}π^{-}π^{0}π^{0}$ and $η' \to 4 π^{0}$ are studied via the process $J/ψ\toγη'$. The branching fractions of $η' \to π^{+}π^{-}π^{+}π^{-}$ and $η' \to π^{+}π^{-}π^{0}$ $π^{0}$ are measured to be $( 8.56 \pm 0.25({\rm stat.}) \pm 0.23({\rm syst.}) ) \times {10^{ - 5}}$ and $(2.12 \pm 0.12({\rm stat.}) \pm 0.10({\rm syst.})) \times {10^{ - 4}}$, respectively, which are consistent with previous measurements but with improved precision. No significant $η' \to 4 π^{0}$ signal is observed, and the upper limit on the branching fraction of this decay is determined to be less than $1.24 \times {10^{-5}}$ at the $90\%$ confidence level. In addition, an amplitude analysis of $η' \to π^{+}π^{-}π^{+}π^{-}$ is performed to extract the doubly virtual isovector form factor $α$ for the first time. The measured value of $α=1.22 \pm 0.33({\rm stat.}) \pm 0.04({\rm syst.})$, is in agreement with the prediction of the VMD model.

hep-ex↗
arXiv2023

Study of the decay $J/ψ\to ϕπ^{0}η$

Based on $(10.09 \pm 0.04) \times 10^9$ $J/ψ$ events collected with the BESIII detector operating at the BEPCII collider, a partial wave analysis of the decay $J/ψ\to ϕπ^{0}η$ is performed. We observe for the first time two new structures on the $ϕη$ invariant mass distribution, with statistical significances of $24.0σ$ and $16.9σ$; the first with $J^{\rm PC}$ = $1^{+-}$, mass M = (1911 $\pm$ 6 (stat.) $\pm$ 14 (sys.))~MeV/$c^{2}$, and width $Γ= $ (149 $\pm$ 12 (stat.) $\pm$ 23 (sys.))~MeV, the second with $J^{\rm PC}$ = $1^{--}$, mass M = (1996 $\pm$ 11 (stat.) $\pm$ 30 (sys.))~MeV/$c^{2}$, and width $Γ$ = (148 $\pm$ 16 (stat.) $\pm$ 66 (sys.))~MeV. These measurements provide important input for the strangeonium spectrum. In addition, the $f_0(980)-a_0(980)^0$ mixing signal in $J/ψ\to ϕf_0(980) \to ϕa_0(980)^0$ and the corresponding electromagnetic decay $J/ψ\to ϕa_0(980)^0$ are measured with improved precision, providing crucial information to understand the nature of $a_0(980)^0$ and $f_0(980)$.

hep-ex↗
arXiv2023

Measurement of lepton universality parameters in $B^+\to K^+\ell^+\ell^-$ and $B^0\to K^{*0}\ell^+\ell^-$ decays

A simultaneous analysis of the $B^+\to K^+\ell^+\ell^-$ and $B^0\to K^{*0}\ell^+\ell^-$ decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, $q^2$. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of $9$ $\text{fb}^{-1}$. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given $q^2$ interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

hep-ex↗
arXiv2023

Test of lepton universality in $b \rightarrow s \ell^+ \ell^-$ decays

The first simultaneous test of muon-electron universality using $B^{+}\rightarrow K^{+}\ell^{+}\ell^{-}$ and $B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-}$ decays is performed, in two ranges of the dilepton invariant-mass squared, $q^{2}$. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 $\mathrm{fb}^{-1}$. Each of the four lepton universality measurements reported is either the first in the given $q^{2}$ interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

hep-ex↗
arXiv2023

Fraction of $χ_c$ decays in prompt $J/ψ$ production measured in pPb collisions at $\sqrt{s_{NN}}=8.16$ TeV

The fraction of $χ_{c1}$ and $χ_{c2}$ decays in the prompt $J/ψ$ yield, $F_{χc}=σ_{χ_c \to J/ψ}/σ_{J/ψ}$, is measured by the LHCb detector in pPb collisions at $\sqrt{s_{NN}}=8.16$ TeV. The study covers the forward ($1.5<y^*<4.0$) and backward ($-5.0<y^*<-2.5$) rapidity regions, where $y^*$ is the $J/ψ$ rapidity in the nucleon-nucleon center-of-mass system. Forward and backward rapidity samples correspond to integrated luminosities of 13.6 $\pm$ 0.3 nb$^{-1}$ and 20.8 $\pm$ 0.5 nb$^{-1}$, respectively. The result is presented as a function of the $J/ψ$ transverse momentum $p_{T,J/ψ}$ in the range 1$<p_{T, J/ψ}<20$ GeV/$c$. The $F_{χc}$ fraction at forward rapidity is compatible with the LHCb measurement performed in $pp$ collisions at $\sqrt{s}=7$ TeV, whereas the result at backward rapidity is 2.4 $σ$ larger than in the forward region for $1<p_{T, J/ψ}<3$ GeV/$c$. The increase of $F_{χc}$ at low $p_{T, J/ψ}$ at backward rapidity is compatible with the suppression of the $ψ$(2S) contribution to the prompt $J/ψ$ yield. The lack of in-medium dissociation of $χ_c$ states observed in this study sets an upper limit of 180 MeV on the free energy available in these pPb collisions to dissociate or inhibit charmonium state formation.

hep-ex↗
arXiv2023

Precision Measurements of $D_s^+ \to ηe^+ ν_e$ and $D_s^+ \to η^\prime e^+ ν_e$

Precision measurements of the semileptonic decays $D_s^+ \to ηe^+ ν_e$ and $D_s^+ \to η^\prime e^+ ν_e$ are performed with 7.33\,fb$^{-1}$ of $e^+e^-$ collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector. The branching fractions obtained are $\mathcal{B}(D_s^+ \to ηe^{+} ν_e)$ = $(2.255\pm0.039_{\rm stat}\pm 0.051_{\rm syst})\%$ and $\mathcal{B}(D_s^+ \to η^{\prime} e^{+} ν_e)$ = $(0.810\pm0.038_{\rm stat}\pm 0.024_{\rm syst})\%$. Combining these results with the $\mathcal{B}(D^+\toηe^+ ν_e)$ and $\mathcal{B}(D^+\toη^\prime e^+ ν_e)$ obtained from previous BESIII measurements, the $η-η^\prime$ mixing angle in the quark flavor basis is determined to be $ϕ_{\rm P} = (40.0\pm2.0_{\rm stat}\pm0.6_{\rm syst})^\circ$. Moreover, from the fits to the partial decay rates of $D_s^+ \to ηe^+ ν_e$ and $D_s^+ \to η^\prime e^+ ν_e$, the products of the hadronic transition form factors $f_+^{η^{(\prime)}}(0)$ and the modulus of the $c\to s$ Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ are determined by using different hadronic transition form factor parametrizations. Based on the two-parameter series expansion, the products $f^η_+(0)|V_{cs}| = 0.4519\pm0.0071_{\rm stat}\pm0.0065_{\rm syst}$ and $f^{η^\prime}_+(0)|V_{cs}| = 0.525\pm0.024_{\rm stat}\pm0.009_{\rm syst}$ are extracted. All results determined in this work supersede those measured in the previous BESIII analyses based on the 3.19 fb$^{-1}$ subsample of data at 4.178 GeV.

hep-ex↗
arXiv2023

Observation of the hindered electromagnetic Dalitz decay $ψ(3686) \to e^+ e^- η_c$

Using a data sample of $(448.1 \pm 2.9)\times10^6 ~ψ(3686)$ decays collected at an $e^+ e^-$ center-of-mass energy of $3.686~\rm{GeV}$ by the BESIII detector at BEPCII, we report an observation of the hindered electromagnetic Dalitz decay $ψ(3686) \to e^+ e^- η_c$ with a significance of $7.9σ$. The branching fraction is determined to be $\mathcal{B} (ψ(3686) \to e^+ e^- η_c) = (3.77 \pm 0.40_{\rm stat.} \pm 0.18_{\rm syst.})\times 10^{-5}$, agreeing well with the prediction of the vector meson dominance model. This is the first measurement of the electromagnetic Dalitz transition between the $ψ(3686)$ and the $η_c$, which provides new insight into the electromagnetic properties of this decay, and offers new opportunities to measure the absolute branching fractions of $η_c$ decays.

hep-ex↗
arXiv2023

Precision measurement of $\it{CP} $ violation in the penguin-mediated decay $B_s^{0}\rightarrowϕϕ$

A flavor-tagged time-dependent angular analysis of the decay $B_s^{0}\rightarrowϕϕ$ is performed using $pp$ collision data collected by the LHCb experiment at $\sqrt{s}=13$ TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The $\it{CP}$-violating phase and direct $\it{CP}$-violation parameter are measured to be $ϕ_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009 $ rad and $|λ|=1.004\pm 0.030 \pm 0.009 $, respectively, assuming the same values for all polarization states of the $ϕϕ$ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using $pp$ collisions at center-of-mass energies of 7 and 8 TeV, yielding $ϕ_{s\bar{s}s} = -0.074 \pm 0.069 $ rad and $|λ|=1.009 \pm 0.030$. This is the most precise study of time-dependent $\it{CP} $ violation in a penguin-dominated $B$ meson decay. The results are consistent with $\it{CP} $ symmetry and with the Standard Model predictions.

hep-ex↗
arXiv2023

Study of $e^+e^-\toηϕ$ at center-of-mass energies from 3.773 to 4.600 GeV

We present a study of the process $e^{+}e^{-}\toηϕ$ using data samples collected with the BESIII detector corresponding to an integrated luminosity of 15.03 fb$^{-1}$ at 23 center-of-mass energies from 3.773 to 4.600 GeV. The Born cross sections are measured at each energy and a coherent fit to cross-section lineshape is performed using a Breit-Wigner parametrization to search for charmonium-like vector states. No significant signals of the $Y(4230)$ and $Y(4360)$ resonances are observed.

hep-ex↗
arXiv2023

Observation of the decays $B_{(s)}^{0}\to D_{s1}(2536)^{\mp}K^{\pm}$

This paper reports the observation of the decays $B_{(s)}^{0}\to D_{s1}(2536)^{\mp}K^{\pm}$ using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of $9\,\mathrm{fb}^{-1}$. The branching fractions of these decays are measured relative to the normalisation channel $B^{0}\to \overline{D}^{0}K^{+}K^{-}$. The $D_{s1}(2536)^{-}$ meson is reconstructed in the $\overline{D}^{*}(2007)^{0}K^{-}$ decay channel and the products of branching fractions are measured to be $$\mathcal{B}(B_{s}^{0}\to D_{s1}(2536)^{\mp}K^{\pm})\times\mathcal{B}(D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-})=(2.49\pm0.11\pm0.12\pm0.25\pm0.06)\times 10^{-5}, $$ $$\mathcal{B}(B^{0}\to D_{s1}(2536)^{\mp}K^{\pm})\times\mathcal{B}(D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-}) = (0.510\pm0.021\pm0.036\pm0.050)\times 10^{-5}.$$ The first uncertainty is statistical, the second systematic, and the third arises from the uncertainty of the branching fraction of the $B^{0}\to \overline{D}^{0}K^{+}K^{-}$ normalisation channel. The last uncertainty in the $B_{s}^{0}$ result is due to the limited knowledge of the fragmentation fraction ratio, $f_{s}/f_{d}$. The significance for the $B_{s}^{0}$ and $B^{0}$ signals is larger than $10\,σ$. The ratio of the helicity amplitudes which governs the angular distribution of the $D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-}$ decay is determined from the data. The ratio of the $S$- and $D$-wave amplitudes is found to be $1.11\pm0.15\pm 0.06$ and its phase $0.70\pm0.09\pm 0.04$ rad, where the first uncertainty is statistical and the second systematic.

hep-ex↗
arXiv2023

Study of the doubly Cabibbo-suppressed decays $D^+_s\to K^+K^+π^-$ and $D^+_s\to K^+K^+π^-π^0$

Based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, the experimental studies of the doubly Cabibbo-suppressed decays $D^+_s\to K^+K^+π^-$ and $D^+_s\to K^+K^+π^-π^0$ are reported. We determine the absolute branching fraction of $D^+_s\to K^+K^+π^-$ to be (${1.23^{+0.28}_{-0.25}}({\rm stat})\pm0.06({\rm syst})$) $\times 10^{-4}$. No significant signal of $D^+_s\to K^+K^+π^-π^0$ is observed and the upper limit on its decay branching fraction at 90\% confidence level is set to be $1.7\times10^{-4}$.

hep-ex↗
arXiv2023

Measurement of the $Λ_{b}^{0}\to Λ(1520) μ^{+}μ^{-}$ differential branching fraction

The branching fraction of the rare decay $Λ_{b}^{0}\to Λ(1520) μ^{+}μ^{-}$ is measured for the first time, in the squared dimuon mass intervals, $q^2$, excluding the $J/ψ$ and $ψ(2S)$ regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of $9\ \mathrm{fb}^{-1}$. The result in the highest $q^{2}$ interval, $q^{2} >15.0\ \mathrm{GeV}^2/c^4$, where theoretical predictions have the smallest model dependence, agrees with the predictions.

hep-ex↗
arXiv2023

Observation of the $ψ(3686)$ decays into $Σ^{+}\barΣ^{-}ω$ and $Σ^{+}\barΣ^{-}{\mathcalϕ}$

Based on $(27.08\pm 0.14)\times10^{8}$ $ψ(3686)$ events collected with the BESIII detector operating at the BEPCII collider, the $ψ(3686)\toΣ^{+}\barΣ^{-}ω$ and $Σ^{+}\barΣ^{-}ϕ$ decays are observed for the first time with statistical significances of 13.8$σ$ and 7.6$σ$, respectively. The corresponding branching fractions are measured to be $\mathcal{B}(ψ(3686)\toΣ^{+}\barΣ^{-}ω)=(1.90 \pm 0.18 \pm 0.21) \times 10^{-5}$ and $\mathcal{B}(ψ(3686)\toΣ^{+}\barΣ^{-}ϕ)=(2.96 \pm 0.54 \pm 0.41) \times 10^{-6}$, where the first uncertainties are statistical and the second systematic.

hep-ex↗
arXiv2023

Observation of $Ξ_b^0 \rightarrow Ξ_c^+ D_s^-$ and $Ξ_b^- \rightarrow Ξ_c^0 D_s^-$ decays

The $Ξ_b^0 \rightarrow Ξ_c^+ D_s^-$ and $Ξ_b^- \rightarrow Ξ_c^0 D_s^-$ decays are observed for the first time using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of $\sqrt{s}=13\mathrm{TeV}$, corresponding to an integrated luminosity of $5.1\mathrm{fb}^{-1}$. The relative branching fractions times the beauty-baryon production cross-sections are measured to be \begin{align*} \mathcal{R}\left(\frac{Ξ_b^0}{Λ_b^0}\right) \equiv \frac{σ\left(Ξ_b^0\right)}{σ\left(Λ_b^0\right)} \times \frac{\mathcal{B}\left(Ξ_b^0 \rightarrow Ξ_c^+ D_s^-\right)}{\mathcal{B}\left(Λ_b^0 \rightarrow Λ_c^0 D_s^-\right)} =(15.8\pm1.1\pm0.6\pm7.7)\%, \mathcal{R}\left(\frac{Ξ_b^-}{Λ_b^0}\right) \equiv \frac{σ\left(Ξ_b^-\right)}{σ\left(Λ_b^0\right)} \times \frac{\mathcal{B}\left(Ξ_b^- \rightarrow Ξ_c^0 D_s^-\right)}{\mathcal{B}\left(Λ_b^0 \rightarrow Λ_c^0 D_s^-\right)} =(16.9\pm1.3\pm0.9\pm4.3)\%, \end{align*} where the first uncertainties are statistical, the second systematic, and the third due to the uncertainties on the branching fractions of relevant charm-baryon decays. The masses of $Ξ_b^0$ and $Ξ_b^-$ baryons are measured to be $m_{Ξ_b^0}=5791.12\pm0.60\pm0.45\pm0.24\mathrm{MeV}/c^2$ and $m_{Ξ_b^-}=5797.02\pm0.63\pm0.49\pm0.29\mathrm{MeV}/c^2$, where the uncertainties are statistical, systematic, and those due to charm-hadron masses, respectively.

hep-ex↗
arXiv2023

Measurement of the branching fractions of the singly Cabibbo-suppressed decays $Λ_{c}^{+}\to pη$ and $Λ_{c}^{+}\to pω$

Based on 4.5 $\mbox{fb$^{-1}$}$ $e^{+}e^{-}$ collision data collected with BESIII detector at seven energy points between 4.600 and 4.699 GeV, the branching fractions for $Λ_{c}^{+}\to pη$ and $Λ_{c}^{+}\to pω$ were measured by means of single-tag method. The branching fractions of $Λ_{c}^{+}\to pη$ and $Λ_{c}^{+}\to pω$ are determined to be $(1.57\pm0.11_{\rm {stat}}\pm0.04_{\rm{syst}})\times10^{-3}$ and $(1.11\pm0.20_{\rm{stat}}\pm0.07_{\rm{syst}})\times10^{-3}$, with a statistical significance of greater than 10 $σ$ and 5.7 $σ$, respectively. These results are consistent with the previous measurements by BESIII, LHCb and Belle, and the result of $Λ_{c}^{+}\to pη$ is the most precise to date.

hep-ex↗
arXiv2023

Observation and branching fraction measurement of the decay $Ξ_b^-\toΛ_b^0π^-$

The decay $Ξ_b^-\toΛ_b^0π^-$ is observed using a proton-proton collision data sample collected at center-of-mass energy $\sqrt{s}=13$ TeV with the LHCb detector, corresponding to an integrated luminosity of 5.5 fb$^{-1}$. This process is mediated by the $s\to u\bar{u}d$ quark-level transition, where the $b$ quark in the $Ξ_b^-$ baryon is a spectator in the decay. Averaging the results obtained using the two $Λ_b^0$ decay modes, $Λ_b^0\toΛ_c^+π^-$ and $Λ_b^0\toΛ_c^+π^-π^+π^-$, the relative production ratio is measured to be $(f_{Ξ_b^-}/f_{Λ_b^0}){\cal{B}}(Ξ_b^-\toΛ_b^0π^-)=(7.3\pm0.8\pm0.6)\times10^{-4}$. Here the uncertainties are statistical and systematic, respectively, and $f_{Ξ_b^-}(f_{Λ_b^0})$ is the fragmentation fraction for a $b$ quark into a $Ξ_b^-$ ($Λ_b^0$) baryon. Using an independent measurement of $f_{Ξ_b^-}/f_{Λ_b^0}$, the branching fraction ${\cal{B}}(Ξ_b^-\toΛ_b^0π^-)=(0.89\pm0.10\pm0.07\pm0.29)\%$ is obtained, where the last uncertainty is due to the assumed SU(3) flavor symmetry in the determination of $f_{Ξ_b^-}/f_{Λ_b^0}$.

hep-ex↗
arXiv2023

Search for $J/ψ$ weak decays containing $D$ meson

Using a sample of about 10 billion $J/ψ$ events with the BESIII detector, we search for the weak decays of $J/ψ\to \bar{D}^0π^0 + c.c.$, $J/ψ\to \bar{D}^0η+ c.c.$, $J/ψ\to \bar{D}^0ρ^0 + c.c.$, $J/ψ\to D^-π^+ + c.c.$, and $J/ψ\to D^-ρ^+ + c.c.$. Since no significant signal is observed, we set the upper limits of the branching fractions of these decays to be $\mathcal{B}(J/ψ\to \bar{D}^0π^0 + c.c.) < 4.7 \times 10^{-7}$, $\mathcal{B}(J/ψ\to \bar{D}^0η+ c.c.) < 6.8 \times 10^{-7}$, $\mathcal{B}(J/ψ\to \bar{D}^0ρ^0 + c.c.) < 5.2 \times 10^{-7}$, $\mathcal{B}(J/ψ\to D^-π^+ + c.c.) < 7.0 \times 10^{-8}$, and $\mathcal{B}(J/ψ\to D^-ρ^+ + c.c.) < 6.0 \times 10^{-7}$ at the 90\% confidence level.

hep-ex↗