3,403 research outputs found
Production of doubly heavy baryons via Higgs boson decays
We systematically analyzed the production of semi-inclusive doubly heavy
baryons (, and ) for the process through four main Higgs decay
channels within the framework of non-relativistic QCD. The contributions from
the intermediate diquark states, ,
, , , and , have been taken into consideration.
The differential distributions and three main sources of the theoretical
uncertainties have been discussed. At the High Luminosity Large Hadron
Collider, there will be about 0.43 events of ,
6.32 events of and 0.28 events of
produced per year. There are fewer events produced at the Circular Electron
Positron Collider and the International Linear Collider, about events of , events of and
events of in operation.Comment: 15 pages, 3 figures, 7 table
Dynamic material model of annealed soda-lime glass
Glass is an omnipresent material which is widely used as façade in buildings. Damage of glass windows and the associated glass fragments induced by impact and blast loads impose great threats to people in the vicinity. Much effort has been directed towards understanding glass material properties, and modeling of glass window responses to impact and blast loads. For reliable predictions of glass structure performances under dynamic loadings, an accurate dynamic constitutive model of annealed float glass, which is commonly used for glass windows, is therefore needed. In current practice, the Johnson-Holmquist Ceramic (JH2) model is most commonly used in simulating glass plate responses to impact and blast loads. In this study, the accuracy of the JH2 model in modeling annealed float glass material, especially at high strain rate is examined in detail. Static compressive tests and dynamic compressive tests using Split Hopkinson Pressure Bar (SHPB) are carried out on soda-lime glass specimens sampled from commercially used annealed float glass panes.These testing results are used together with the authors' previous testing data and data reported by other researchers in the literature to determine the constitutive constants for the JH2 model, including Equation of State (EOS), strength criterion and strain-rate effect. The JH2 model with new material constants is then programmed in commercial code LS-DYNA. To verify the model, it is used to simulate a SHPB compressive test on a 15 mm by 15 mm (diameter by length) glass specimen, a field blasting test on a laminated glass window of 1.5 m by 1.2 m in dimension, and a full-scale laboratory windborne debris impact test on a laminated glass window. The simulation results demonstrate that the JH2 model with the new material constants for annealed glass gives good predictions of glass material and glass window responses to impact and blast loads
Degeneracy Relations in QCD and the Equivalence of Two Systematic All-Orders Methods for Setting the Renormalization Scale
The Principle of Maximum Conformality (PMC) eliminates QCD renormalization
scale-setting uncertainties using fundamental renormalization group methods.
The resulting scale-fixed pQCD predictions are independent of the choice of
renormalization scheme and show rapid convergence. The coefficients of the
scale-fixed couplings are identical to the corresponding conformal series with
zero -function. Two all-orders methods for systematically implementing
the PMC-scale setting procedure for existing high order calculations are
discussed in this article. One implementation is based on the PMC-BLM
correspondence \mbox{(PMC-I)}; the other, more recent, method \mbox{(PMC-II)}
uses the -scheme, a systematic generalization of the minimal
subtraction renormalization scheme. Both approaches satisfy all of the
principles of the renormalization group and lead to scale-fixed and
scheme-independent predictions at each finite order. In this work, we show that
PMC-I and PMC-II scale-setting methods are in practice equivalent to each
other. We illustrate this equivalence for the four-loop calculations of the
annihilation ratio and the Higgs partial width . Both methods lead to the same resummed (`conformal') series up to
all orders. The small scale differences between the two approaches are reduced
as additional renormalization group -terms in the pQCD expansion
are taken into account. We also show that {\it special degeneracy relations},
which underly the equivalence of the two PMC approaches and the resulting
conformal features of the pQCD series, are in fact general properties of
non-Abelian gauge theory.Comment: 7 pages, 1 figur
Excited doubly heavy baryons production via Higgs decays
Through the interaction of Higgs with heavy quarks in standard model, we have
systematically studied and predicted the production of excited doubly heavy
baryons based on non-relativistic QCD theory. The decay widths, differential
distributions, and major theoretical uncertainties of the excited doubly heavy
baryons via the process are discussed in detail. The spin and color
quantum number of the intermediate -wave diquark state can be ,
, , , and , with . The contributions from
all summed -wave states can be about , and of the
-wave states for the production of , and ,
accordingly. Therefore, there will be about 0.41 events of
, 6.35 events of and 0.28 events
of produced per year at the HL-LHC, and a smaller number of events
would be produced at the CEPC or ILC but with a cleaner background to be
measured by the experiments.Comment: 17 pages, 4 figures, 6 tables. Accepted by European Physical Journal
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