In a recent note [1], J. M. Cline criticised our idea that, besides the known Higgs boson with mass $m_h=$ 125 GeV, the Higgs field $\cal H$ could exhibit a relatively narrow, second resonance with theoretical mass $(M_H)^{\rm Theor} = 690\,(30)$ GeV. His criticism addresses both the basic theory part as well as our phenomenological analysis, in which we show that the characteristic, experimental signature of the proposed new resonance may already be visible in various LHC data. As for the comparison with experiment, Cline altogether ignores our most recent article [2], except for its title, and limits himself to just show an old plot from a preprint from five years ago. For this reason, as far as the phenomenology is concerned, there is nothing to reply to. Instead, we will briefly reply to his criticism on the theoretical part. Our conclusion is that Cline has completely ignored basic aspects of our work.
This overview describes several science cases at the Electron-Ion-Collider (EIC) experiment which are traditional to general particle physics. It has an emphasis on connections between future measurements at the EIC and the physics topics explored at high-energy frontier colliders. It covers several selected topics, such as parton density functions, multi-quarks states, correlations of final-state particles, precision QCD measurements and forward jet physics. We will discuss possible EIC measurements that can improve previous experimental results obtained at high-energy (HEP) experiments.
In this conference, I have talked about two scenarios in which the out-of-equilibrium production of dark matter (DM) particles in the early universe is unavoidable. In the first one \cite{bhattacharyya_freezing-dark_2018}, we extend the standard model (SM) of particle physics by an extra $U(1)$ gauge group under which all the SM particles are neutral. We then consider DM candidates interacting only with the new spin-1 gauge boson, a heavy $Z^\prime$. We assume the presence of heavy beyond the SM fermions charged under both extra $U(1)$ and SM $SU(3)_c$, allowing for a feeble connection between DM and gluons. In the second scenario \cite{bernal_spin-2_2018}, we assume that the interactions between DM and SM particles are only mediated by gravitons and massive spin-2 fields, being therefore suppressed by the Planck and some intermediate scales, respectively. In both models, we show that the SM particles are able to produce the right amount of DM candidates via freeze-in at most in the early stages of the radiation era, for DM mass in the range $10^{-3}-10^{14}$ GeV. We have shown that if heavy mediators were produced on-shell within a period of entropy production in the early universe, as in the post-inflationary reheating, the DM relic density may be enhanced by many orders of magnitude relative to the usual instantaneous reheating approximation.
Our community has to apply {\em non}-perturbative QCD on different levels of flavor dynamics in strange, charm \& beauty hadrons and even for top quarks. We need {\em consistent} parameterization of the CKM matrix and describe weak decays of beauty hadrons with {\em many-body} final states. It is crucial to use the {\em Wilsonian} OPE as much as possible and discuss "duality" in the worlds of quarks and hadrons. The pole mass of heavy quarks is {\em not} well-defined on the {\em non}-perturbative level -- i.e., it is {\em not} Borel summable in total QCD. We need a novel team to combine the strengths of our tools from MEP and HEP.
Pions were predicted by H. Yukawa as force carriers of the inter-nucleon forces, and were detected in 1947. Today they are known to be bound states of quarks and anti-quarks of the two lightest flavours. They satisfy Bose statistics, and are the lightest particles of the strong interaction spectrum. Determination of the parameters of the Standard Model, including the masses of the lightest quarks, has only recently reached high precision on the lattice. Pions are also known to be pseudo-Goldstone bosons of spontaneously broken approximate axial-vector symmetries, and a probe of their properties and interactions at high precision tests our knowledge of the strong interactions. While also being a probe of the solution of the strong interactions on the computer, which is known as lattice gauge theory. Despite their long history, there are significant experimental and theoretical challenges in determining their properties at high precision. Examples include the lifetime of the neutral pion, and the status of their masses and decay widths in effective field theories. Pion-pion scattering has been studied for several decades using general methods of field theory such as dispersion relations based on analyticity, unitarity and crossing. Knowledge from these theoretical methods are used to confront high precision experimental data, and to analyze them to extract information on their scattering and phase shift parameters. This knowledge is crucial for estimating the Standard Model contributions to the anomalous magnetic moment of the muon, which is being probed at Fermilab in ongoing experiments. Other sensitive tests include the rare decay of the eta meson into three pions, which represents an isospin violating decay. The present article briefly reviews these important developments.
QCD/HQET matching for the heavy-quark field [A.G. Grozin, arXiv:1004.2662 [hep-ph] ] and heavy–light quark currents [S. Bekavac, A.G. Grozin, P. Marquard, J.H. Piclum, D. Seidel, M. Steinhauser, Nucl. Phys. B 833 (2010) 46 [ arXiv:0911.3356 [hep-ph] ] with three-loop accuracy is discussed.
We analyse the so-called violations of quark-hadron duality in Finite Energy Sum Rules (FESRs) with the LR correlator, through the study of the possible high-energy behavior of the LR spectral function, taking into account all known short-distance constraints and the experimental tau-decay data. In particular we show that the use of pinched weights (PWs) allows to determine with high accuracy the dimension six and eight contributions in the Operator-Product Expansion, O 6 = ( − 4.3 − 0.7 + 0.9 ) ⋅ 10 − 3 GeV 6 and O 8 = ( − 7.2 − 5.3 + 4.2 ) ⋅ 10 − 3 GeV 8 [M. Gonzalez-Alonso, A. Pich, and J. Prades, Phys. Rev. D81 (2010) 074007, arXiv:1001.2269 [hep-ph] ; M. Gonzalez-Alonso, A. Pich, and J. Prades, Phys. Rev. D82 (2010) 014019, arXiv:1004.4987 [hep-ph] ].