Search results for "Pair production"
showing 10 items of 431 documents
Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider
2020
Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these longlived particles (LLPs) can decay far from the interaction vertex of the primary proton–proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP…
Soft-dielectron excess in proton-proton collisions at $\sqrt{s}$ = 13 TeV
2021
Physical review letters 127(4), 042302 (2021). doi:10.1103/PhysRevLett.127.042302
Pair creation in electric fields, anomalies, and renormalization of the electric current
2018
We investigate the Schwinger pair production phenomena in spatially homogeneous strong electric fields. We first consider scalar QED in four-dimensions and discuss the potential ambiguity in the adiabatic order assignment for the electromagnetic potential required to fix the renormalization subtractions. We argue that this ambiguity can be solved by invoking the conformal anomaly when both electric and gravitational backgrounds are present. We also extend the adiabatic regularization method for spinor QED in two-dimensions and find consistency with the chiral anomaly. We focus on the issue of the renormalization of the electric current $\langle j^\mu \rangle$ generated by the created pairs.…
From elliptic curves to Feynman integrals
2018
In this talk we discuss Feynman integrals which are related to elliptic curves. We show with the help of an explicit example that in the set of master integrals more than one elliptic curve may occur. The technique of maximal cuts is a useful tool to identify the elliptic curves. By a suitable transformation of the master integrals the system of differential equations for our example can be brought into a form linear in $\varepsilon$, where the $\varepsilon^0$-term is strictly lower-triangular. This system is easily solved in terms of iterated integrals.
"Table 5" of "Measurement of the $ZZ$ Production Cross Section in $pp$ Collisions at $\sqrt{s}$ = 13 TeV with the ATLAS Detector"
2016
Cross section extrapolated to total phase space and all Z boson decays. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity uncertainty, the second is the luminosity uncertainty.
"Table 4" of "Measurement of the $ZZ$ Production Cross Section in $pp$ Collisions at $\sqrt{s}$ = 13 TeV with the ATLAS Detector"
2016
Measured fiducial cross section in all $\ell^+\ell^-\ell'^+\ell'^-$ channels combined, where $\ell, \ell' = e, \mu$. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity uncertainty, the second is the luminosity uncertainty.
"Table 5" of "Measurements of four-lepton production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector"
2016
The total uncertainty covariance matrix for measured differential cross sections in $p_\mathrm{T}^{4\ell}$ bins in fiducial volume. The matrix elements are in unit of $[$fb/TeV$]^2$.
"Table 4" of "Measurements of four-lepton production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector"
2016
The total uncertainty covariance matrix for measured differential cross sections in $m_{4\ell}$ bins in fiducial volume. The matrix elements are in unit of $[$fb/TeV$]^2$.
"Table 3" of "Measurement of the WW+WZ Production Cross Section Using the Lepton+Jets Final State at CDF II"
2009
Cross section from method two.
"Table 1" of "Measurement of the WW+WZ Production Cross Section Using the Lepton+Jets Final State at CDF II"
2009
Cross section from the combined analysis.. Error is combined statistics and systematics.