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At least 199 records · Page 11
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DOE OSTI2023

Measurement of the branching fractions for Cabibbo-suppressed decays D + → K + K - π + π 0 and D ( s ) + → K + π - π + π 0 at Belle

We present measurements of the branching fractions for the singly Cabibbo-suppressed decays and , and the doubly Cabibbo-suppressed decay , based on of data recorded by the Belle experiment at the KEKB e + ⁢e - collider. We measure these modes relative to the Cabibbo-favored modes D + → K - ⁢π + ⁢π + ⁢π 0 and D$^{+}_{s}$ → K + ⁢K -⁢ π + ⁢π 0 . Our results for the ratios of branching fractions are $\mathscr{B}$⁡(D + →K + ⁢K -⁢ π + ⁢π 0 )/$\mathscr{B}$⁡(D + → K - ⁢π + ⁢π + ⁢π 0 ) =(11.32±0.13±0.26)%, $\mathscr{B}$⁡(D + →K + π - ⁢π + ⁢π 0 )/$\mathscr{B}$(D + →K -⁢ π + ⁢π + ⁢π 0 ) =(1.68±0.11±0.03)%, and $\mathscr{B}$⁡(D$^{+}_{s}$ → K + ⁢π - π + ⁢π 0 )/$\mathscr{B}$⁡(D$^{+}_{s}$ → K + ⁢K - π + π 0 ) =(17.13±0.62±0.51)%, where the uncertainties are statistical and systematic, respectively. The second value corresponds to (5.83 ±0.42) ×tan 4 ⁡θ C , where θ C is the Cabibbo angle; this value is larger than other measured ratios of branching fractions for a doubly Cabibbo-suppressed charm decay to a Cabibbo-favored decay. Multiplying these results by world average values for $\mathscr{B}$⁡(D + → K - ⁢π + ⁢π + ⁢π 0 ) and $\mathscr{B}$⁡(D$^{+}_{s}$ → K + ⁢K - π + π 0 ) yields $\mathscr{B}$( + →K + ⁢K -⁢ π + ⁢π 0 ) = (7.08±0.08±0.16±0.20)×10 -3 , $\mathscr{B}$⁡(D + → K +⁢ π - π + ⁢π 0 ) =(1.05±0.07±0.02±0.03)×10 -3 , and $\mathscr{B}$⁡(D$^{+}_{s}$ → K + ⁢π - π + ⁢π 0 ) =(9.44±0.34±0.28±0.32)×10 -3 , where the third uncertainty is due to the branching fraction of the normalization mode. The first two results are consistent with, but more precise than, the current world averages. The last result is the first measurement of this branching fraction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of the branching fraction and search for CP violation in D 0 → K $^{0}_{S}$ K $^{0}_{S}$ ⁢π + ⁢π - decays at Belle

We measure the branching fraction for the Cabibbo-suppressed decay D 0 → K $^{0}_{S}$ K $^{0}_{S}$ ⁢π + ⁢π - and search for CP violation via a measurement of the CP asymmetry A CP as well as the T-odd triple-product asymmetry a$^{T}_{CP}$. We use 922 fb -1 of data recorded by the Belle experiment, which ran at the KEKB asymmetric-energy e + ⁢e - collider. The branching fraction is measured relative to the Cabibbo-favored normalization channel D 0 → K $^{0}_{S}$ ⁢π + ⁢π - ; the result is $\mathscr{B}$⁡( D 0 → K $^{0}_{S}$ K $^{0}_{S}$ ⁢π + ⁢π - )=[4.79±0.08⁢(stat)±0.10⁢(syst)±0.31⁢(norm)]×10 -4 , where the first uncertainty is statistical, the second is systematic, and the third is from uncertainty in the normalization channel. We also measure A CP =[-2.51±1.44⁢(stat)$^{+0.11}_{-0.10}$⁢(syst)]%, and a$^{T}_{CP}$=[-1.95±1.42⁢(stat)$^{+0.14}_{-0.12}⁢$(syst)]%. These results show no evidence of CP violation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of the branching fraction and CP asymmetry of B 0 →π 0 ⁢π 0 decays using 198×1⁢0 6 $B\overline{B}$ pairs in Belle II data

We report measurements of the branching fraction and C P asymmetry in B 0 → π 0 π 0 decays reconstructed at Belle II in an electron-positron collision sample containing 198 × 10 6 B B ¯ pairs. We measure a branching fraction B ( B 0 → π 0 π 0 ) = ( 1.38 ± 0.27 ± 0.22 ) × 10 - 6 and a C P asymmetry A C P ( B 0 → π 0 π 0 ) = - 0.14 ± 0.46 ± 0.07 , where the first uncertainty is statistical and the second is systematic.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Measurement of the production of a $W$ boson in association with a charmed hadron in $pp$ collisions at $\sqrt{s}$ = $\mathrm{13 TeV}$ with the ATLAS detector

The production of a $W$ boson in association with a single charm quark is studied using 140 fb –1 of $\sqrt{s}$ = $13$ $\mathrm{TeV}$ proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. The charm quark is tagged by the presence of a charmed hadron reconstructed with a secondary-vertex fit. The $W$ boson is reconstructed from the decay to either an electron or a muon and the missing transverse momentum present in the event. The charmed mesons reconstructed are D + → K – π + π + and D *+ → D 0 π + → (K – π + ) π + and the charge conjugate decays in the fiducial regions where $p$ T ($e,μ$) > 30 GeV, |$η(e,μ)$| < 2.5, $p$ T (D (*) ) > 8 GeV, and |$η$(D (*) )| < 2.2. The integrated and normalized differential cross sections as a function of the pseudorapidity of the lepton from the $W$ boson decay, and of the transverse momentum of the charmed hadron, are extracted from the data using a profile likelihood fit. The measured total fiducial cross sections are ${σ}_{fid}^{OS – SS}$ (W – + D + ) = 50.2 ± 0.2 ${(stat)}_{–2.3}^{+2.4}$(syst) pb, ${σ}_{fid}^{OS – SS}$ (W + + D – ) = 48.5 ± 0.2 ${(stat)}_{–2.2}^{+2.3}$(syst) pb, ${σ}_{fid}^{OS – SS}$ (W – + D *+ ) = 51.1 ± 0.4 ${(stat)}_{–1.8}^{+1.9}$(syst) pb, ${σ}_{fid}^{OS – SS}$ (W + + D *– ) = 50.0 ± 0.4 ${(stat)}_{–1.8}^{+1.9}$(syst) pb. Results are compared with the predictions of next-to-leading-order quantum chromodynamics calculations performed using state-of-the-art parton distribution functions. Additionally, the ratio of charm to anticharm production cross sections is studied to probe the $s$-$\bar{s}$ quark asymmetry. The ratio is found to be ${R}_{c}^{±}$= 0.971 ± 0.006 (stat) ± 0.011 (syst). The ratio and cross-section measurements are consistent with the predictions obtained with parton distribution function sets that have a symmetric $s$-$\bar{s}$ sea, indicating that any $s$-$\bar{s}$ asymmetry in the Bjorken-x region relevant for this measurement is small.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

SMEFT probes in future precision DIS experiments

We analyze the potential of future high-energy deep-inelastic scattering (DIS) experiments to probe new physics within the framework of the Standard Model effective field theory (SMEFT). We perform a detailed study of SMEFT probes at a future Large Hadron-electron Collider (LHeC) and a Future Circular lepton-hadron Collider (FCC-eh) machine, and extend previous simulations of the potential of an electron-ion collider (EIC) to include 𝑍-boson vertex corrections. Precision 𝑍-pole constraints on vertex corrections suffer from numerous degeneracies in the Wilson-coefficient parameter space. We find that both the LHeC and the FCC-eh can help remove these degeneracies present in the existing global fits of precision 𝑍-pole observables and LHC data. The FCC-eh and LHeC will in many cases improve upon the existing precision electroweak bounds on the SMEFT parameter space. This highlights the important role of precision DIS measurements for new physics studies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Interfacing electron and neutrino quasielastic scattering cross sections with the spectral function in GENIE

Progress in neutrino-nucleus cross section models is being driven by the need for highly accurate predictions for the neutrino oscillation community. These sophisticated models are being developed within a microscopic description of the nucleus with the goal of encompassing all reaction modes relevant for the accelerator neutrino program. The disconnect between these microscopic models and the event generators that will be used in the next generation of experiments represents a critical obstacle that must be overcome in order to precisely measure the neutrino oscillation parameters. To this end we have developed a hadron tensor interface for lepton-nucleus quasielastic (QE) scattering within the GENIE event generator as a proof of principle, with the broader goal of creating an efficient pipeline for incorporating advanced theoretical models in event generators. As a demonstration of this interface we have implemented the spectral function model into GENIE by connecting theorist provided fortran code through the hadron tensor interface. The spectral function model offers a more complete description of the nuclear ground state, as well as the ability to provide quantifiable theoretical uncertainties. Finally, we validate this implementation and compare its predictions against data and against QE models already available in GENIE.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗