We present results for the Higgsstrahlung process within the geneva Monte Carlo framework. We combine the fully differential next-to-next-to-leading order (NNLO) calculation with the higher-order ...resummation in the 0-jettiness resolution variable (beam thrust). The resulting parton-level events are further showered and hadronized by pythia8. The beam thrust resummation is carried out to next-to-next-to-leading logarithmic accuracy, consistently incorporating all singular virtual and real NNLO corrections. It thus provides a natural perturbative connection between the NNLO calculation and the parton shower regime, including a systematic assessment of perturbative uncertainties. In this way, observables which are inclusive over the additional radiation are correct to NNLO, while the description of 0-jet -like resummation variables is improved beyond the parton shower approximation. We provide predictions for the 13 TeV LHC.
The treatment of γ5 in dimensional regularization leads to ambiguities in field-theoretic calculations, of which one example is the coefficient of a particular term in the four-loop gauge beta ...functions of the standard model. Using Weyl consistency conditions, we present a scheme-independent relation between the coefficient of this term and a corresponding term in the three-loop Yukawa beta functions, where a semi-naïve treatment of γ5 is sufficient, thereby fixing this ambiguity. We briefly outline an argument by which the same method fixes similar ambiguities at higher orders.
We consider gravitational collapse for the axially symmetric Einstein-Vlasov system. We investigate the weak cosmic censorship conjecture in the case of highly prolate initial data and we investigate ...the "only if"part of the Hoop conjecture. Shapiro and Teukolsky initiated a similar study in 1991 Formation of Naked Singularities: The Violation of Cosmic Censorship, Phys. Rev. Lett. 66, 994 (1991)PRLTAO0031-900710.1103/PhysRevLett.66.994 where they found support that the weak cosmic censorship conjecture was violated for sufficiently prolate spheroidal initial data. More recently, independent studies of this problem have been carried out by Yoo et al. 3D simulation of spindle gravitational collapse of a collisionless particle system, Classical Quantum Gravity 34, 105010 (2017)CQGRDG0264-938110.1088/1361-6382/aa6ad5 and by East Cosmic Censorship Upheld in Spheroidal Collapse of Collisionless Matter, Phys. Rev. Lett. 122, 231103 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.231103. A common feature in these works is that the initial data are dustlike. Dust can be considered as a singular case of matter described by the Einstein-Vlasov system. The original motivation by Shapiro and Teukolsky to study this problem is based on the Lin-Mestel-Shu instability for gravitational collapse of uniform spheroids in the case of dust in Newtonian gravity. We argue that the Lin-Mestel-Shu solution is not relevant for studying the weak cosmic censorship conjecture of the Einstein-Vlasov system and we argue that dustlike initial data is also not relevant. To investigate collapse of highly prolate spheroidal configurations for the Einstein-Vlasov system is nevertheless interesting in view of the Hoop conjecture. By choosing highly prolate initial data the weak cosmic censorship conjecture is seriously tested. We carry out such a study for initial data which are not dustlike. We find formation of an apparent horizon in all cases we consider, which provides support for the weak cosmic censorship conjecture. In our tests of the Hoop conjecture we compute the polar circumference CH,p at the time when the apparent horizon forms and find that it is less than 12% above 4πM, where M is the irreducible mass of the apparent horizon, which agrees with the spirit of the Hoop conjecture.
We present a comprehensive analysis of the γW interference radiative correction to the neutron β-decay matrix element. Within a dispersion relations approach, we compute the axial-vector part of the ...γW box amplitude □γWA in terms of the isoscalar part of the FγW3 interference structure function. Using the latest available phenomenology for FγW3 from the nucleon elastic, resonance, deep-inelastic, and Regge regions, we find the real part of the box correction to be □γWA = 3.90 (9) × 10−3. This improved correction gives a theoretical estimate of the CKM matrix element |Vud|2 = 0.94805 (26), which represents a 4σ violation of unitarity.
The concept of Drazin-Theta matrices are extended for rectangular matrices and defined W-weighted Drazin-Theta matrices. Several characterizations and the algebraic and geometrical interpretations of ...Drazin-Theta matrices are obtained here. The Drazin-Theta matrices are special cases of W-weighted Drazin-Theta matrices. All the characterizations obtained for W-weighted Drazin-Theta matrices are applicable to its dual, that is Theta-Drazin matrices. Further, the concept of W-weighted Drazin-Theta matrices are applied in solving certain types of linear system of equations.
It has recently been suggested that the Standard Model Higgs boson could act as the inflaton while minimally coupled to gravity-given that the gravity sector is extended with an α R 2 term and the ...underlying theory of gravity is of Palatini, rather than metric, type. In this paper, we revisit the idea and correct some shortcomings in earlier studies. We find that, in this setup, the Higgs can indeed act as the inflaton and that the tree-level predictions of the model for the spectral index and the tensor-to-scalar ratio are n s ≃ 0.941 , r ≃ 0.3 / ( 1 + 10 − 8 α ) , respectively, for a typical number of e -folds, N = 50 , between horizon exit of the pivot scale k = 0.05 Mpc − 1 and the end of inflation. Even though the tensor-to-scalar ratio is suppressed compared to the usual minimally coupled case and can be made compatible with data for large enough α , the result for n s is in severe tension with the Planck results. We briefly discuss extensions of the model.
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