Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userNLO Multijet Merging for Higgs Production Beyond the VBF Approximation
90
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present results of the simulation of electroweak Higgs boson production at the Large Hadron Collider using the NLO multi-jet merging framework provided by the general purpose event generator Herwig 7. For the hard processes, we use the HJets library for the computation of the $mathcal{O}(alpha^3 alpha_{s}^{n-2})$ matrix elements for $pp to h+n$ jet production at LO for $n=2,3,4$ and NLO for $n=2,3$.
rate research
Read More
We consider electro-weak Higgs plus three jets production at NLO QCD beyond strict VBF acceptance cuts. We investigate, for the first time, how accurate the VBF approximation is in these regions and within perturbative uncertainties, by a detailed comparison of full and approximate calculations. We find that a rapidity gap between the tagging jets guarantees a good approximation, while an invariant mass cut alone is not sufficient, which needs to be confronted with experimental choices. We also find that a significant part of the QCD corrections can be attributed to Higgs-Strahlungs-type topologies.
We study the leptoquark model of Buchmuller, Ruckl and Wyler, focusing on a particular type of scalar ($R_2$) and vector ($U_1$) leptoquark. The primary aim is to perform the calculations for leptoquark production and decay at next-to-leading order (NLO) to establish the importance of the NLO contributions and, in particular, to determine how effective the narrow-width-approximation (NWA) is at NLO. For both the scalar and vector leptoquarks it is found that the NLO contributions are large, with the larger corrections occurring for the case vector leptoquarks. For the scalar leptoquark it is found that the NWA provides a good approximation for determining the resonant peak, however the NWA is not as effective for the vector leptoquark. For both the scalar and vector leptoquarks there are large contributions away from the resonant peak, which are missing from the NWA results, and these make a significant difference to the total cross-section.
We report on results for the NLO corrected differential distributions $dsigma/dp_T$ and $dsigma/dy$ for the process $p + pto H + X$, where $p_T$ and $y$ are the transverse momentum and rapidity of the Higgs-boson $H$ respectively and $X$ denotes the inclusive hadronic state. All QCD partonic subprocesses have been included. The computation is carried out in the limit that the top-quark mass $m_t to infty$. Our calculations reveal that the dominant subprocess is given by $g + g to H + X$ but the reaction $g + q(bar q) to H + X$ is not negligible. Also the $K$-factor representing the ratio between the next-to-leading order and leading order differential distributions varies from 1.4 to 1.7 depending on the kinematic region and choice of parton densities.
We consider soft gluon emission corrections to the production of a top-antitop pair in association with a Higgs boson at hadron colliders. In particular, we present a soft-gluon resummation formula for this production process and gather all elements needed to evaluate it at next-to-next-to-leading logarithmic order. We employ these results to obtain approximate next-to-next-to-leading order (NNLO) formulas, and implement them in a bespoke parton-level Monte Carlo program which can be used to calculate the total cross section along with arbitrary differential distributions. We use this tool to study the phenomenological impact of the approximate NNLO corrections, finding that they increase the total cross section and the differential distributions which we evaluated in this work.
For certain classes of Beyond the Standard Model theories, including composite Higgs models, the coupling of the Higgs to gauge bosons can be different from the Standard Model one. In this case, the multi-boson production via vector boson fusion (VBF) can be hugely enhanced in comparison to the SM production one due to the lack of cancellation in longitudinal vector boson scattering. Among these processes, triple Higgs boson production in VBF plays a special role - its enhancement is especially spectacular due to the absence of background from transversely polarised vector bosons in the final state. While the rates from $ppto jjhhh$ production in vector boson fusion are too low at the LHC and even at future 33 TeV $pp$ colliders, we have found that the 100 TeV $pp$ future circular collider (FCC) has the unique opportunity to probe the $hVV$ coupling far beyond the LHC sensitivity. We have evaluated the $ppto jjhhh$ rates as a function of deviation from the $hVV$ coupling and have found that the background is much smaller than the signal for observable signal rates. We also found that the 100 TeV $pp$ FCC can probe the $hVV$ coupling up to the permille level, which is far beyond the LHC reach. These results highlight a special role of the $hhh$ VBF production and stress once more the importance of the 100 TeV $pp$ FCC.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
