A
bstract
We examine the observability of heavy neutrino (
ν
h
) signatures of a U(1)′ enlarged Standard Model (SM) encompassing three heavy Majorana neutrinos alongside the known light neutrino ...states at the the Large Hadron Collider (LHC). We show that heavy neutrinos can be rather long-lived particles producing distinctive displaced vertices that can be accessed in the CERN LHC detectors. We concentrate here on the gluon fusion production mechanism
gg
→
H
1,2
→
ν
h
ν
h
, where
H
1
is the discovered SM-like Higgs and
H
2
is a heavier state, yielding displaced leptons following
ν
h
decays into weak gauge bosons. Using data collected by the end of the LHC Run 2, these signatures would prove to be accessible with negligibly small background.
A
bstract
In this paper, we discuss the potential of observing heavy neutrino (
ν
h
) signatures of a U(1)
B
−
L
enlarged Standard Model (SM) encompassing three heavy Majorana neutrinos alongside the ...known light neutrino states at the Large Hadron Collider (LHC). We exploit the theoretical decay via a heavy (non-SM-like) Higgs boson and
Z
′
production followed by
ν
h
→
l
±
W
∓(∗)
and
ν
h
→
ν
l
Z
(∗)
decays, ultimately yielding a 3
l
+ 2
j
+
E
T
miss
signature and, depending upon how boosted the final state objects are, we define different possible selections aimed at improving the signal to background ratio in LHC Run 2 data for a wide range of heavy neutrino masses.
Binned data frames are a generalisation of multi-dimensional histograms, represented in a tabular format with one category per row containing the labels, bin contents, uncertainties and so on. Pandas ...is an industry-standard tool, which provides a data frame implementation complete with routines for data frame manipultion, persistency, visualisation, and easy access to “big data” scientific libraries and machine learning tools. FAST (the Faster Analysis Software Taskforce) has developed a generic approach for typical binned HEP analyses, driving the summary of ROOT Trees to multiple binned DataFrames with a yaml-based analysis description. Using Continuous Integration to run subsets of the analysis, we can monitor and test changes to the analysis itself, and deploy documentation automatically. This report describes this approach using examples from a public CMS tutorial and details the benefit over traditional methods.
We investigate the potential of the Large Hadron Collider (LHC) to probe one of the most compelling beyond the Standard Model frameworks-walking technicolor (WTC), involving strong dynamics and ...having a slowly running (walking) new strong coupling. For this purpose we use recent LHC Run 2 data to explore the full parameter space of the minimal WTC model using dilepton signatures from heavy neutral Z′ and Z′′ resonances predicted by the model. This signature is the most promising one for discovery of WTC at the LHC for the low-intermediate values of the g˜ coupling-one of the principle parameters of WTC. We have demonstrated complementarity of the dilepton signals from both resonances, established the most up-to-date limit on the WTC parameter space, and provided projections for the LHC potential to probe the WTC parameter space at higher future luminosities and upgraded energy. We have explored the whole four-dimensional parameter space of the model and have found the most conservative limit on the WTC scale MA above 3 TeV for the low values of g˜, which is significantly higher than previous limits established by the LHC collaborations.
We investigate the possibility of detectable 2-Higgs Doublet Model (2HDM) type-II cross-sections at the High-Luminosity phase of the Large Hadron Collider (HL-LHC) for the production of the Standard ...Model (SM)-like Higgs boson (\(h\)) in association with a single top (anti)quark over the parameter space region corresponding to the so-called `wrong-sign solution' of the bottom (anti)quark Yukawa coupling. We isolate the latter by using the toolbox Magellan, which performs Markov Chain Monte Carlo (MCMC) scans in the presence of all current theoretical and experimental constraints, which relevance is accounted for accurately by using built-in Bayesian statistical methods. It is found that the allowed points in the 2HDM type-II parameter space of the aforementioned kind would not only provide inclusive rates considerably above those of the equivalent SM process but also distributions in several kinematical observables that are very different from the SM, both of which can help disentangle the SM from the 2HDM hypothesis. This difference is a consequence of the bottom-gluon fusion sub-process, which in the 2HDM becomes dominant over all others, with the latter remaining very close to the SM yields. We prove that this phenomenology would be observable at the HL-LHC for the illustrative example of \(h\) to bottom-antibottom quark decays.
The ultimate motivation of our study is to look for signs of physics beyond the Standard Model (BSM). We investigate whether different jet clustering techniques might be more or less suited to the ...particular final states of interest. In particular, we are interested in fully hadronic final states emerging from the decay chain of the Standard Model like Higgs boson into pairs of light Higgs states, the latter in turn decaying into bottom-anti bottom pairs. We show that, the ability of selecting the multi-jet final state and to reconstruct invariant masses of the Higgs bosons from it depend strongly on the choice of acceptance cuts, resolution parameters and reconstruction algorithm as well as its settings. Hence, we indicate the optimal choice of the latter for the purpose of establishing such a benchmark as a BSM signal. We then repeat the exercise for a heavy Higgs boson cascading into two SM-like Higgs states, obtaining similar results.
We assess the performance of different jet-clustering algorithms, in the presence of different resolution parameters and reconstruction procedures, in resolving fully hadronic final states emerging ...from the chain decay of the discovered Higgs boson into pairs of new identical Higgs states, the latter in turn decaying into bottom-antibottom quark pairs. We show that, at the Large Hadron Collider (LHC), both the efficiency of selecting the multi-jet final state and the ability to reconstruct from it the masses of the Higgs bosons (potentially) present in an event sample depend strongly on the choice of acceptance cuts, jet-clustering algorithm as well as its settings. Hence, we indicate the optimal choice of the latter for the purpose of establishing such a benchmark Beyond the SM (BSM) signal.
Phys. Rev. D 99, 055004 (2019) We investigate the potential of the Large Hadron Collider (LHC) to probe one
of the most compelling Beyond the Standard Model (BSM) frameworks --- Walking
Technicolor ...(WTC), involving strong dynamics and having a slowly running
(walking) new strong coupling. For this purpose we use recent LHC Run2 data to
explore the full parameter space of the minimal WTC model using dilepton
signatures from heavy neutral $Z^{\prime}$ and $Z^{\prime\prime}$ resonances
predicted by the model. This signature is the most promising one for discovery
of WTC at the LHC for the low-intermediate values of the $\tilde g$ coupling --
one of the principle parameters of WTC. We have demonstrated complementarity of
the dilepton signals from both resonances, have established the most up-to-date
limit on the WTC parameter space, and provided projections for the the LHC
potential to probe the WTC parameter space at higher future luminosities and
upgraded energy. We have explored the whole four-dimensional parameter space of
the model and have found the most conservative limit on the WTC scale $M_A$
above 3 TeV for the low values of $\tilde g$ which is significantly higher than
previous limits established by the LHC collaborations.
In this paper, we discuss the potential of observing heavy neutrino ($\nu_h$)
signatures of a $U(1)_{B-L}$ enlarged Standard Model (SM) encompassing three
heavy Majorana neutrinos alongside the known ...light neutrino states at the Large
Hadron Collider (LHC). We exploit the theoretical decay via a pair of heavy
(non-SM-like) Higgs boson and $Z'$ production followed by $\nu_h \rightarrow
l^\pm W^{\mp (*)}$ and $\nu_h \rightarrow \nu_l Z^{(*)}$ decays, ultimately
yielding a $3l+2j+E_{T}^{\rm{miss}}$ signature and, depending upon how boosted
the final state objects are, we define different possible selections aimed at
improving the signal to background ratio in LHC Run 2 data for a wide range of
heavy neutrino masses.
We present results of B -> vector-vector (VV) and B -> vector-axial vector (VA) decays B0 -> phi X (X = phi, rho+ or rho0), B+ -> phi K(*)+, B0 -> K*K*, B0 -> rho+b_1- and B+ -> K*0a_1+. The largest ...dataset used for these results is based on 465 * 10^6 Y(4S) -> BB decays, collected with the BABAR detector at the PEP-II B meson factory located at the Stanford Linear Accelerator Center (SLAC).
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