scholarly journals X, Y, Z Search at Belle II

2019 ◽  
Vol 202 ◽  
pp. 01001
Author(s):  
Elisabetta Prencipe
Keyword(s):  
Phase Ii ◽  
Precise Measurement ◽  
Belle Collaboration ◽  
Potential Models ◽  
Decay Modes ◽  
Belle Ii ◽  
Production Mechanisms ◽  
Integrated Luminosity

Search for exotics has increased importance since the observation of the X(3872), 13 years ago, announced by the Belle Collaboration. The observation of pentaquark states by LHCb, and the Z-charged states observed at Belle and BES III have raised even more the attention to the field. Presently several states are observed that do not fit potential models, and looking for them in different production mechanisms and search for their decay modes it is important, as well as to do precise measurement of their mass, width, lineshape. We shortly report in this note about the plan in searching for exotics at Belle II at KEK (Tsukuba, Japan), that just ended the Phase-II running period, and show the first re-discovery results using 5 pb−1 integrated luminosity.

scholarly journals Study of nonleptonic B(s)∗→ M1M2 (M = D,Ds,π,K) weak decays with factorization approach

2015 ◽  
Vol 30 (27) ◽  
pp. 1550162 ◽  
Author(s):  
Qin Chang ◽  
Pan-Pan Li ◽  
Xiao-Hui Hu ◽  
Lin Han
Keyword(s):  
Flavor Physics ◽  
Branching Fractions ◽  
Form Factors ◽  
Approximation Formula ◽  
Heavy Flavor ◽  
Transition Form ◽  
Factorization Approach ◽  
Decay Modes ◽  
Weak Decays ◽  
Belle Ii

Motivated by the experiments of heavy flavor physics at running LHC and upgrading SuperKEKB/Belle-II in the future, the nonleptonic [Formula: see text] [Formula: see text] weak decays are studied in this paper. The amplitudes are calculated with factorization approach, and the transition form factors [Formula: see text] are evaluated within BSW model. With the reasonable approximation [Formula: see text], our predictions of branching fractions are presented. Numerically, the CKM-favored tree-dominated [Formula: see text] and [Formula: see text] decays have the largest branching fractions of the order [Formula: see text], and hence will be firstly observed by forthcoming Belle-II experiment. However, most of the other decay modes have the branching fractions [Formula: see text] and thus are hardly to be observed soon. Besides, for the possible detectable [Formula: see text] decays with branching fractions [Formula: see text], some useful ratios, such as [Formula: see text], etc. are presented and discussed in detail.

scholarly journals The fate of $$\mathbf{V}_\mathbf{1}$$ vector leptoquarks: the impact of future flavour data

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
C. Hati ◽  
J. Kriewald ◽  
J. Orloff ◽  
A. M. Teixeira
Keyword(s):  
Simplified Model ◽  
Meson Decay ◽  
Final States ◽  
Decay Modes ◽  
Flavour Violation ◽  
Belle Ii ◽  
The Impact ◽  
Lepton Flavour ◽  
Model Approach

AbstractMotivated by the recent experimental progress on the B-meson decay anomalies (in particular the angular observables in $$B\rightarrow K^*\mu \mu $$ B → K ∗ μ μ ), we rely on a simplified-model approach to study the prospects of vector leptoquarks in what concerns numerous flavour observables, identifying several promising decay modes which would allow to (indirectly) probe such an extension. Our findings suggest that the confirmation of the B-meson decay anomalies, in parallel with positive signals (at Belle II or LHCb) for $$\tau \rightarrow \phi \mu $$ τ → ϕ μ , $$B_{(s)}$$ B ( s ) -meson decays to $$\tau ^+ \tau ^-$$ τ + τ - and $$\tau ^+ \mu ^-$$ τ + μ - ($$\tau ^+ e^-$$ τ + e - ) final states, as well as an observation of certain charged lepton flavour violation decays (at COMET or Mu2e), would contribute to strengthen the case for this scenario. We also illustrate how the evolution of the experimental determination of $$R_{D^{(*)}}$$ R D ( ∗ ) could be instrumental in falsifying an explanation of the anomalous B-meson decay data via a vector $$V_1$$ V 1 leptoquark.

scholarly journals Study of $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ decays to charmonia and three light hadrons

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
◽  
R. Aaij ◽  
A. S. W. Abdelmotteleb ◽  
C. Abellán Beteta ◽  
F. J. Abudinen Gallego ◽  
...  
Keyword(s):  
Branching Fractions ◽  
Theoretical Description ◽  
Proton Collision ◽  
Proton Proton ◽  
Decay Modes ◽  
Charged Hadrons ◽  
Lhcb Detector ◽  
Proton Proton Collision ◽  
First Time ◽  
Integrated Luminosity

Abstract Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1 collected with the LHCb detector, seven decay modes of the $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + meson into a J/ψ or ψ(2S) meson and three charged hadrons, kaons or pions, are studied. The decays $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + → (ψ(2S) → J/ψπ+π−)π+, $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + → ψ(2S)π+π−π+, $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + → J/ψK+π−π+ and $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + → J/ψK+K−K+ are observed for the first time, and evidence for the $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + → ψ(2S)K+K−π+, decay is found, where J/ψ and ψ(2S) mesons are reconstructed in their dimuon decay modes. The ratios of branching fractions between the different $$ {\mathrm{B}}_{\mathrm{c}}^{+} $$ B c + decays are reported as well as the fractions of the decays proceeding via intermediate resonances. The results largely support the factorisation approach used for a theoretical description of the studied decays.

scholarly journals Decay Chain Reconstruction at Belle II

2019 ◽  
Vol 214 ◽  
pp. 06023 ◽  
Author(s):  
Francesco Tenchini ◽  
Jo-Frederik Krohn
Keyword(s):  
Decay Chain ◽  
Vertex Detector ◽  
Decay Modes ◽  
Background Rejection ◽  
Particle Decay ◽  
Pixel Sensors ◽  
Flexible Framework ◽  
Global Fit ◽  
Belle Ii ◽  
Consistent Treatment

The Belle II detector underwent commissioning in 2018. Featuring a state of the art vertex detector with innovative pixel sensors, it will record collisions of e+e- beams from the SuperKEKB accelerator which is slated to provide luminosities 40 times higher than KEKB. This will bring new opportunities and challenges for physicists seeking to perform precision measurements, as increasingly precise vertex position reconstruction and background rejection power is needed to take advantage of the unprecedented statistics provided. We discuss the vertex reconstruction techniques available that make such measurements possible and present an approach to particle decay reconstruction based on the global fit of the full decay chain, implemented using a Kalman Filter. This technique is especially well suited to the treatment of processes with neutral decays. It allows for improved background rejection, access to a larger number of decay modes and a flexible framework for consistent treatment of measurement uncertainties.

scholarly journals XYZ states at BESIII

2019 ◽  
Vol 212 ◽  
pp. 02003
Author(s):  
Zhentian Sun
Keyword(s):  
Fine Structure ◽  
Partial Wave ◽  
Decay Mode ◽  
Cross Sections ◽  
Precise Measurement ◽  
Partial Wave Analysis ◽  
Experimental Results ◽  
Wave Analysis ◽  
Decay Modes

In this proceeding, I report the most recent experimental results from BESIII about the XYZ sates. Two new X(3872) decay modes are observed, which is X(3872) → ωJ/ψ and X(3872) → π0χc1(1P). Precise measurement of cross sections of various channels reveal more fine structure about Y states. To study the property of Zc states, the Jp of Zc(3900) is determined with partial wave analysis, and a hint of new decay mode of Zc±(3900) → ρ±ηc are observed.

scholarly journals Search for the process e+e−→D*(2007) with the CMD-3 detector

2019 ◽  
Vol 212 ◽  
pp. 02011
Author(s):  
D. N. Shemyakin ◽  
R. R. Akhmetshin ◽  
A. N. Amirkhanov ◽  
A. V. Anisenkov ◽  
V. M. Aulchenko ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Mass Energy ◽  
Decay Modes ◽  
Center Of Mass Energy ◽  
Upper Limit ◽  
Integrated Luminosity

A search for the process e+e−→ D*0(2007) has been performed with the CMD-3 detector at the VEPP-2000 e+e−-collider. Two main decay modes of the D*0(2007) decay, D0π0 and D0γ, followed by D0 → K+π−π+π−are used in this analysis. With an integrated luminosity of 3.7 pb−1 collected at the center-of-mass energy Ec.m. =2006.62 MeV our preliminary upper limit is BD*0→e+ e− <1.6× 10−6 at 90%C.L.

scholarly journals Measuring the Higgs self-coupling via Higgs-pair production at a 100 TeV p–p collider

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Michelangelo L. Mangano ◽  
Giacomo Ortona ◽  
Michele Selvaggi
Keyword(s):  
Pair Production ◽  
Detailed Analysis ◽  
Confidence Level ◽  
Precise Measurement ◽  
Higgs Potential ◽  
Detector Performance ◽  
Proton Proton ◽  
Decay Channels ◽  
Systematic Uncertainties ◽  
Integrated Luminosity

AbstractHiggs pair production provides a unique handle for measuring the strength of the Higgs self interaction and constraining the shape of the Higgs potential. Among the proposed future facilities, a circular 100 TeV proton–proton collider would provide the most precise measurement of this crucial quantity. In this work, we perform a detailed analysis of the most promising decay channels and derive the expected sensitivity of their combination, assuming an integrated luminosity of 30 $$\hbox {ab}^{-1}$$ ab - 1 . Depending on the assumed detector performance and systematic uncertainties, we observe that the Higgs self-coupling will be measured with a precision in the range 3.4–7.8% at 68% confidence level.

scholarly journals Development of the Dataset Searcher Webapp for finding data on the Belle II computing grid

2020 ◽  
Vol 245 ◽  
pp. 04021
Author(s):  
Kim Smith ◽  
David Dossett ◽  
Martin Sevior
Keyword(s):  
Large Scale ◽  
Easy Access ◽  
Software Framework ◽  
Scientific Experiment ◽  
Computing Grid ◽  
Belle Ii ◽  
Run Time ◽  
Integrated Luminosity

In any large scale scientific experiment involving enormous quantities of data it is crucial that everyone involved has quick and easy access to all the relevant datasets for their research. By the end of the run time of the Belle II experiment there will be a projected 50 ab−1 of integrated luminosity making it no exception. Until now the only method for locating data of interest was by looking up hand written tables that needed to be regularly updated. In this paper, a new webapp built on the DIRAC software framework will be presented which aims to be the new standard for not only locating data but also storing all its associated metadata.

scholarly journals Higgs portal to dark matter and $$B\rightarrow K^{(*)}$$ decays

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Aliaksei Kachanovich ◽  
Ulrich Nierste ◽  
Ivan Nišandžić
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Decay Rates ◽  
Dark Sector ◽  
Mixing Angle ◽  
Decay Modes ◽  
Simultaneous Study ◽  
Belle Ii ◽  
Displaced Vertex ◽  
Higgs Portal

Abstract We consider a Higgs portal model in which the 125-GeV Higgs boson mixes with a light singlet mediator $$h_2$$h2 coupling to particles of a Dark Sector and study potential $$b\rightarrow s h_2$$b→sh2 decays in the Belle II experiment. Multiplying the gauge-dependent off-shell Standard-Model b-s-Higgs vertex with the sine of the Higgs mixing angle does not give the correct b-s-$$h_2$$h2 vertex. We clarify this issue by calculating the b-s-$$h_2$$h2 vertex in an arbitrary $$R_\xi $$Rξ gauge and demonstrate how the $$\xi $$ξ dependence cancels from physical decay rates involving an on-shell or off-shell $$h_2$$h2. Then we revisit the $$b\rightarrow s h_2$$b→sh2 phenomenology and point out that a simultaneous study of $$B\rightarrow K^* h_2$$B→K∗h2 and $$B\rightarrow K h_2$$B→Kh2 helps to discriminate between the Higgs portal and alternative models of the Dark Sector. We further advocate for the use of the $$h_2$$h2 lifetime information contained in displaced-vertex data with $$h_2$$h2 decaying back to Standard-Model particles to better constrain the $$h_2$$h2 mass or to reveal additional $$h_2$$h2 decay modes into long-lived particles.

scholarly journals Measurement of the absolute branching fraction of the inclusive decay $$\Lambda _c^+ \rightarrow K_S^0X$$

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
M. Ablikim ◽  
M. N. Achasov ◽  
P. Adlarson ◽  
S. Ahmed ◽  
M. Albrecht ◽  
...  
Keyword(s):  
Branching Fraction ◽  
Branching Fractions ◽  
Relative Deviation ◽  
Final State ◽  
Decay Modes ◽  
The Absolute ◽  
Inclusive Decay ◽  
Integrated Luminosity

AbstractWe report the first measurement of the absolute branching fraction of the inclusive decay $$\Lambda _c^+ \rightarrow K_S^0X$$ Λ c + → K S 0 X . The analysis is performed using an $$e^+e^-$$ e + e - collision data sample corresponding to an integrated luminosity of 567 $$\hbox {pb}^{-1}$$ pb - 1 taken at $$\sqrt{s}$$ s = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored $${\bar{\Lambda }}_c^-$$ Λ ¯ c - decay modes and the double-tag technique, this absolute branching fraction is measured to be $${\mathcal {B}}(\Lambda _c^+ \rightarrow K_S^0X)=(9.9\pm 0.6\pm 0.4)\%$$ B ( Λ c + → K S 0 X ) = ( 9.9 ± 0.6 ± 0.4 ) % , where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is $$(18.7\pm 8.3)\%$$ ( 18.7 ± 8.3 ) % , which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.

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