European Physical Society

Abstract No abstract

The IceCube Neutrino Observatory at the South Pole is a Cherenkov-based detector inside antarctic ice with a volume of about 1 cubic kilometer. IceCube consists of 5160 Digital Optical Modules (DOMs) attached like beads on 86 vertical strings, instrumenting depths from 1450 - 2450 m below the surface of the glacier. The bottom central region of IceCube has densely spaced DOMs and is known as DeepCore, which is capable of detecting atmospheric neutrinos at GeV energies. Atmospheric neutrinos can be used to study neutrino oscillations over wide ranges of energies and baselines. We present a measurement of the oscillation parameters $\Delta m^2_{32}$ and $\theta_{23}$ using the disappearance of atmospheric muon neutrinos with a new data sample from IceCube DeepCore. This sample consists of improved data calibration, detector simulation, and data processing, as well as a more sophisticated treatment of systematics. These results are of comparative precision to measurements from long-baseline neutrino oscillation experiments.

An undulator-based positron source is proposed for the future International Linear Collider (ILC): the high-intense electron beam passes through a helical undulator to produce a multi-MeV circularly polarized photon beam before it is directed to the interaction point (IP). The photon beam strikes a thin target to produce electron-positron pairs. A maximum active undulator length of 231 m is expected to be appropriate for the ILC center-of-mass energy range Ecm ≥ 250 GeV. Since the photon produced by the undulator is created with an opening angle, some of these photons will hit the superconducting undulator wall. Therefore, photon masks must be installed along the undulator line to keep the power deposited into the undulator walls due to the synchrotron radiation (primary photons) at an acceptable level (1 W/m). This paper will discuss the power deposited into the undulator walls due to the primary photons and secondary particles. Masks inserted in the undulator line are discussed, assuming ideal and realistic undulator fields. In terms of materials, copper or tungsten are considered in detail.

The cross sections of the Z boson production in association with at least two b jets as a function of various kinematic variables are measured in pp collisions at $\sqrt{s} =$ 13 TeV using 137 ${\textrm{fb}^{-1}}$ of data collected by the CMS experiment at LHC. The Z boson decays to electrons or muons are considered with leading (sub-leading) lepton transverse momentum $p_\textrm{T}$ > 35 (25) GeV and pseudorapidity |$\eta$|< 2.4, and the invariant mass within 71 and 111 GeV. Jets are selected with $p_\textrm{T}$ > 30 GeV and |$\eta$| < 2.4. The results are compared to various QCD calculations.

Through this article, we show that the amplitudes for the $b\bar{b} \rightarrow ZH$ in the presence of bottom-Higgs Yukawa coupling can be constructed, up to a few anomalous diagrams, solely from a set of vector form factors of properly grouped classes of diagrams. Thereby, we can completely bypass the subtle issues involving the chiral quantity $\gamma_5$. In the second part, we demonstrate that while computing the $q\bar{q} \rightarrow ZH$ amplitudes in Higgs effective field theory employing a non-anticommuting $\gamma_5$ in dimensional regularization, we need to introduce a four-point effective composite operator to the renormalized Lagrangian in order to retain the physical properties of the amplitude.

In this talk we discuss computations of NLO virtual corrections to four-point gluon-fusion processes; in particular the production of HH, ZH and ZZ. Recently these processes have been computed numerically, but they are not known analytically. We will discuss how one can perform an expansion of these amplitudes in the high-energy limit, and improve the resulting series through the use of Padé approximants.

A transition magnetic moment between active and sterile neutrinos can induce the Primakoff upscattering process at the coherent elastic neutrino nucleus scattering experiments, leading to very stringent limits on the transition dipole coupling as a function of the sterile neutrino mass. Here we discuss how a novel radiative upscattering mode with an additional photon emitted in the final state can lead to exploration of new parameter space in the transition dipole coupling vs. sterile neutrino mass plane and provide distinguishable differential distributions for a Dirac vs Majorana sterile state mediating such a mode.

In a simple extension of the Standard Model (SM) with a second Higgs doublet and a dark singlet scalar, we are able to: (i) explain the MiniBooNE (MB) and Liquid Scintillator Neutrino Detector (LSND) anomalies while remaining compatible with the KARMEN null result, (ii) in the process, obtain a portal to the dark sector, and (iii) account comfortably for the observed value of $(g-2)_\mu$. Three SM singlet neutrinos allow for explaining non-zero neutrino masses via a seesaw Type-I mechanism, with the lighter two states participating in the LSND and MB interactions.

Tokai-to-Kamioka (T2K) is a long baseline neutrino experiment which uses the proton beam at the Japan Particle Accelerator Research Centre (JPARC) to produce a beam of muon neutrinos and antineutrinos. T2K determines neutrino oscillation parameters of interest by comparing the measured neutrino rate and spectrum at a near detector complex, located at JPARC, and at Super-Kamiokande, a water-Cherenkov detector, located 295 km away. T2K is currently undergoing major improvements: the JPARC neutrino beam is increasing in power, the Super-Kamiokande detector has been loaded with 0.02% of Gadolinium, enabling enhanced neutron tagging; and a significant upgrade of the ND280 near detector is scheduled for installation in 2022/23. These proceedings summarise T2K's latest measurements of neutrino oscillations and detail some of the planned improvements, with particular focus on the upcoming near detector upgrade

Within the framework of the $\cal CP$ conserving Two Higgs Doublet Models (2HDM) type I and II we investigate the di-Higgs production at future $e^+e^-$ colliders in order to find effects coming from triple Higgs couplings. We define and explore some benchmark planes that show large values of these couplings, still in agreement with all the relevant theoretical and experimental constraints. Within those planes two production channels are considered: $e^+e^-\to h_ih_jZ$ and $e^+e^-\to h_ih_j\nu\bar{\nu}$, with $h_ih_j=hh,\ HH\ \mathrm{and}\ AA$. We discuss on the sensitivity to $\kappa_\lambda:=\lambda_{hhh}/\lambda_{hhh}^\mathrm{SM}$ and $\lambda_{hhH}$ in the $hh\nu\bar{\nu}$ production and to $\lambda_{hHH}$ ($\lambda_{hAA}$) in the $HH\nu\bar{\nu}$ ($AA\nu\bar{\nu}$) production at CLIC 3 TeV via the cross section distribution on the invariant mass of the final-state Higgs-pair.