Search for f1(1285)→π+π−π0f_1(1285) \to \pi^+\pi^-\pi^0 decay with VES detector

The isospin violating decay $f_1(1285)\to\pi^+\pi^-\pi^0$ has been studied at VES facility. This study is based at the statistics acquired in $\pi^- Be$ interactions at 27, 36.6 and 41 GeV/c in diffractive reaction $\pi^- N \to (f_1 \pi^-) N$. The $f_1(1285) \to \pi^+\pi^-\pi^0$ decay is observed. The ratio of decay probabilities $BR(f_1(1285) \to \pi^+\pi^-\pi^0)$ to $BR(f_1(1285) \to \eta \pi^+\pi^-) \cdot BR(\eta \to \gamma\gamma)$ is $\sim\:1.4$.Comment: 10 pages, 8 figures, presented at XII Conference on Hadron Spectroscop

Study of corrections for anomalous coupling limits due to the possible background BSM contributions

The search of the anomalous couplings is one of the possible ways to find any deviation from the Standard Model. The effective field theory is used to parameterize the anomalous couplings in the Lagrangian with the operators of higher dimensions, constructed from the SM fields. In the classical way, the limits on the Wilson coefficients of these operators are set based on beyond the Standard Model contributions induced for signal process, whereas the ones induced for background processes are assumed to be negligible. This article provides a study of the corrections to the limits on Wilson coefficients by accounting beyond the Standard Model contributions induced for background processes. The studies of $Z(\nu\bar{\nu})\gamma jj$ and $W(\ell\nu)\gamma jj$ productions in $pp$ collisions with $\sqrt{s}=13$ TeV and conditions of the ATLAS experiment at the LHC are used as example. Cases of collected during Run II and expected from Run III integrated luminosities of 139 fb$^{-1}$ and 300 fb$^{-1}$ are considered. The expected 95% CL limits on coefficients $f_\text{T0}/\Lambda^4$, $f_\text{T5}/\Lambda^4$, $f_\text{M0}/\Lambda^4$ and $f_\text{M2}/\Lambda^4$ are obtained both in classical way and in the way, where the corrections from background anomalous contributions are applied. Corrected one-dimensional limits from $Z(\nu\bar{\nu})\gamma jj$ and $W(\ell\nu)\gamma jj$ productions are up to 9.1% and 4.4% (depending on operator) tighter than the classical ones respectively. Corrected combined limits are up to 3.0% (depending on operator) tighter than the classical ones. Corrections to two-dimensional limits are also obtained, corrected contours are more stringent, than the classical ones, and the maximal improvement is of 17.2%

Composite effective field theory signal in case of searching for neutral triple gauge couplings with ZZ→ℓℓννZZ\rightarrow\ell\ell\nu\nu production

In this work manifestations of physics beyond the Standard Model are parameterized with higher-dimension operators and Wilson coefficients using effective field theory. In order to set more stringent experimental limits on the Wilson coefficients it is crucial to use new methods of sensitivity increasing that work independently with luminosity growth. Method of composite anomalous signal allows one to set the limits on Wilson coefficients more precisely and stringent by accounting for impact of EFT operators on background processes in addition to the conventional anomalous contribution from the signal process. This work presents aforementioned methodology applied to the $ZZ\rightarrow\ell\ell\nu\nu$ production, that is sensitive to the neutral triple couplings of gauge bosons $Z$ and $\gamma$. It is found that the main background BSM contribution comes from $WZ\rightarrow\ell\nu\ell\ell$ background. Improvement of the limits on the Wilson coefficients due to this background depends on the coefficient and is up to 57.5% (59.1%) for one- (two-) dimensional limits in linear + quadratic effective field theory model and up to 94.4% for one-dimensional limits in linear effective field theory model.Comment: 11 pages, 5 figures, 4 tables. Submitted to Physics of Atomic Nucle

Beam Test Results of the LHCb Electromagnetic Calorimeter.

The main properties of the LHCb electromagnetic calorimeter and a prototype of the monitoring system was studied at the X7 CERN test-beam facility. A dedicated MC simulation for light propagation in the scintillator tiles was developed and tuned with experimental data