Neutrinos offer a window to physics beyond the Standard Model. In particular, high-energy astrophysical neutrinos, with TeV–PeV energies, may provide evidence of new, “secret” neutrino-neutrino interactions that are stronger than ordinary weak interactions. During their propagation over cosmological distances, high-energy neutrinos could interact with the cosmic neutrino background via secret interactions, developing characteristic energy-dependent features in their observed energy distribution. For the first time, we use a rigorous statistical analysis to look for signatures of secret neutrino interactions in the diffuse flux of high-energy astrophysical neutrinos, based on 6 years of publicly available IceCube High Energy Starting Events. We find no significant evidence for secret neutrino interactions, but place competitive upper limits on the coupling strength of the new mediator through which they occur, in the mediator mass range of 1–100 MeV.

A surprisingly large flux of extraterrestrial high-energy neutrinos was discovered by the IceCube experiment. While the flux of muon neutrinos with energies $E>100\mathrm{TeV}$ is consistent with the extragalactic gamma-ray background determined by Fermi-LAT, the softer component of the cascade neutrino flux at $E<100\mathrm{TeV}$ is larger than expected. Moreover, a gamma-ray excess at high galactic latitudes at energies $E>300\mathrm{GeV}$ was found in the data of Fermi-LAT. The gamma-ray excess at TeV energies and the neutrino excess at $E<100\mathrm{TeV}$ may have a common galactic origin. In this work, we study the possibility that both excesses are caused by interactions of cosmic rays (CRs) with energies up to PeV in the wall of the local bubble. Source of these CRs may be a recent nearby source like Vela. We show that such a scenario can explain the observed CR flux around the knee, while CR interactions in the bubble wall can generate a substantial fraction of the observed astrophysical high-energy neutrino flux below $\sim \mathrm{few}\times 100\mathrm{TeV}$.

After having published the first thunderstorm ground enhancements (TGEs) catalog to explain long-lasting TGEs, we address here problems pertaining to TGE evolution (shape) and atmospheric conditions supporting the origination of the relativistic runaway electron avalanches. We also address the question of radon progeny gamma radiation and its contribution to overall TGE flux. We demonstrate that by using detectors with different energy thresholds we can identify and reliably separate both mechanisms of TGE origination. An analysis of measured energy spectra of TGEs reveals contributions of both processes to the TGE temporal evolution and shape. We also confirm the model of radon progeny radiation during a thunderstorm.

We report a $B$-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope. This work uses $500{\mathrm{deg}}^2$ of SPTpol data, a five-fold increase over the last SPTpol $B$-mode release. As a result, the bandpower uncertainties have been reduced by more than a factor of two, and the measurement extends to lower multipoles: $52<\ell <2301$. Data from both 95 and 150 GHz are used, allowing for three cross-spectra: $95\mathrm{GHz}\times 95\mathrm{GHz}$, $95\mathrm{GHz}\times 150\mathrm{GHz}$, and $150\mathrm{GHz}\times 150\mathrm{GHz}$. $B$-mode power is detected at very high significance; we find $P(BB<0)=5.8\times {10}^{-71}$, corresponding to a $18.1\sigma$ detection of power. With a prior on the galactic dust from Planck, WMAP and BICEP2/Keck observations, the SPTpol $B$-mode data can be used to set an upper limit on the tensor-to-scalar ratio, $r<0.44$ at 95% confidence (the expected $1\sigma$ constraint on $r$ given the measurement uncertainties is 0.22). We find the measured $B$-mode power is consistent with the Planck best-fit $\mathrm{\Lambda }\mathrm{CDM}$ model predictions. Scaling the predicted lensing $B$-mode power in this model by a factor $A_{\mathrm{lens}}$, the data prefer $A_{\mathrm{lens}}=1.17\pm 0.13$. These data are currently the most precise measurements of $B$-mode power at $\ell >320$.

Using loop-tree duality, we relate a renormalized $n$-point $l$-loop amplitude in a quantum field theory to a phase-space integral of a regularized $l$-fold forward limit of a UV-subtracted $(n+2l)$-point tree-amplitude-like object. We show that up to three loops the latter object is easily computable from recurrence relations. This defines an integrand of the loop amplitude with a global definition of the loop momenta. Field and mass renormalization are performed in the on-shell scheme.

We revisit our previous work [Capozzi et al., Phys. Rev. D 95, 096014 (2017)] where neutrino oscillation and nonoscillation data were analyzed in the standard framework with three neutrino families, in order to constrain their absolute masses and to probe their ordering (either normal, NO, or inverted, IO). We include updated oscillation results to discuss best fits and allowed ranges for the two squared mass differences $\delta m^2$ and $\mathrm{\Delta }{m}^2$, the three mixing angles ${\theta }_{12}$, ${\theta }_{23}$, and ${\theta }_{13}$, as well as constraints on the $CP$-violating phase $\delta$, plus significant indications in favor of NO vs IO at the level of $\mathrm{\Delta }{\chi }^2=10.0$. We then consider nonoscillation data from beta decay, from neutrinoless double beta decay (if neutrinos are Majorana), and from various cosmological input variants (in the data or the model) leading to results dubbed as default, aggressive, and conservative. In the default option, we obtain from nonoscillation data an extra contribution $\mathrm{\Delta }{\chi }^2\simeq 2.2$ in favor of NO, and an upper bound on the sum of neutrino masses $\mathrm{\Sigma }<0.15\mathrm{eV}$ at $2\sigma$; both results—dominated by cosmology—can be strengthened or weakened by using more aggressive or conservative options, respectively. Taking into account such variations, we find that the combination of all (oscillation and nonoscillation) neutrino data favors NO at the level of $3.2-3.7\sigma$, and that $\mathrm{\Sigma }$ is constrained at the $2\sigma$ level within $\mathrm{\Sigma }<0.12–0.69\mathrm{eV}$. The upper edge of this allowed range corresponds to an effective $\beta$-decay neutrino mass $m_{\beta }\simeq \mathrm{\Sigma }/3\simeq 0.23\mathrm{eV}$, at the sensitivity frontier of the KATRIN experiment.

We analyze the consistency of electroweak breaking within the simplest high-scale ${\mathrm{SU}(3)}_{\mathrm{c}}\otimes {\mathrm{SU}(2)}_{\mathrm{L}}\otimes {\mathrm{U}(1)}_{\mathrm{Y}}$ type-I seesaw mechanism. We derive the full two-loop renormalization group equations of the relevant parameters, including the quartic Higgs self-coupling of the Standard Model. For the simplest case of bare “right-handed” neutrino mass terms we find that, with large Yukawa couplings, the Higgs quartic self-coupling becomes negative much below the seesaw scale, so that the model may be inconsistent even as an effective theory. We show, however, that the “dynamical” type-I high-scale seesaw with spontaneous lepton number violation has better stability properties.

We propose a model where a long-lived pseudoscalar EeV particle can be produced with sufficient abundance so as to account for the cold dark matter density, despite having a Planck mass suppressed coupling to the thermal bath. Connecting this state to a hidden sterile neutrino sector through derivative couplings, induced by higher dimensional operators, allows one to account for light neutrino masses while having a lifetime that can be much larger than the age of the Universe. Moreover, the same derivative coupling accounts for the production of dark matter in the very first instant of the reheating. Given the sensitivity of the IceCube and ANITA collaborations, we study the possible signatures of such a model in the form of ultrahigh-energy cosmic rays in the neutrino sector, and show that such signals could be detected in the near future.

Vectorlike quarks (VLQs) are potential signatures of physics beyond the standard model at the TeV energy scale, and major effort has been put forward at both the ATLAS and CMS experiments to search for these particles. To make these search results more relatable in the context of most plausible theories of VLQs, it is deemed important to present the analysis results in a general fashion. We investigate the challenges associated with such interpretations of singly produced VLQ searches and propose a generalized, semianalytical framework that allows for a model-independent casting of the results in terms of unconstrained free parameters of the VLQ Lagrangian. We also propose a simple parametrization of the correction factor to the single VLQ production cross section at large decay widths. We illustrate how the proposed framework can be used to conveniently represent statistical limits by numerically reinterpreting results from benchmark ATLAS and CMS analyses.

We propose a novel approach of probing grand unification through precise measurements on the Higgs Yukawa couplings at the LHC. This idea is well motivated by the appearance of effective operators not suppressed by the mass scale of unification $M_{\mathrm{U}}$ in realistic models of unification with the minimal structure of Yukawa sector. Such operators modify the Higgs Yukawa couplings in correlated patterns at scale $M_{\mathrm{U}}$ that hold up to higher-order corrections. The coherences reveal a feature that, the deviation of tau Yukawa coupling relative to its standard model value at the weak scale is the largest one among the third-generation Yukawa couplings. This feature, if verified by the future LHC, can serve as a hint of unification.

Three-body states are critical to the dynamics of many hadronic resonances. We show that lattice QCD calculations have reached a stage where these states can be accurately resolved. We perform a calculation over a wide range of parameters and find all states below inelastic threshold agree with predictions from a state-of-the-art phenomenological formalism. This also illustrates the reliability of the formalism used to connect lattice QCD results to infinite volume physics. Our calculation is performed using three positively charged pions, with different lattice geometries and quark masses.

In the paper, we study the properties of the top-quark $\overline{\mathrm{MS}}$ running mass computed from its on-shell mass by using both the four-loop $\overline{\mathrm{MS}}$-on-shell relation and the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct magnitude of the strong running coupling of the perturbative series, its prediction avoids the conventional renormalization scale ambiguity, and thus a more precise pQCD prediction can be achieved. After applying the PMC to the four-loop $\overline{\mathrm{MS}}$-on-shell relation and taking the top-quark on-shell mass $M_t=172.9\pm 0.4\mathrm{GeV}$ as an input, we obtain the renormalization scale-invariant $\overline{\mathrm{MS}}$ running mass at the scale $m_t$, e.g., $m_t(m_t)\simeq 162.6\pm 0.4\mathrm{GeV}$, in which the error is the squared average of those from $\mathrm{\Delta }{\alpha }_s(M_Z)$, $\mathrm{\Delta }{M}_t$, and the approximate error from the uncalculated five-loop terms predicted by using the Padé approximation approach.

We investigate the predictive power of transverse-momentum-dependent (TMD) distributions as a function of the light-cone momentum fraction $x$ and the hard scale $Q$ defined by the process. We apply the saddle-point approximation to the unpolarized quark and gluon transverse momentum distributions and evaluate the position of the saddle point as a function of the kinematics. We determine quantitatively that the predictive power for an unpolarized transverse momentum distribution is maximal in the large-$Q$ and small-$x$ region. For cross sections the predictive power of the TMD factorization formalism is generally enhanced by considering the convolution of two distributions, and we explicitly consider the case of $Z$ and $H^0$ boson production. In the kinematic regions where the predictive power is not maximal, the distributions are sensitive to the nonperturbative hadron structure. Thus, these regions are critical for investigating hadron tomography in a three-dimensional momentum space.

Through data analysis, we present new sets of nonperturbative fragmentation functions (FFs) for ${\mathrm{\Lambda }}_c^{+}$ baryon both at leading and next-to-leading order and, for the first time, at next-to-next-to-leading order in the minimal subtraction factorization scheme with five massless quarks. The FFs are determined by fitting all available data of inclusive single ${\mathrm{\Lambda }}_c^{+}$ baryon production in $e^{+}{e}^{-}$ annihilation taken by the OPAL Collaboration at CERN LEP1 and Belle Collaboration at KEKB. We also estimate the uncertainties in the ${\mathrm{\Lambda }}_c^{+}$ FFs as well as in the corresponding observables. In a completely different approach based on the Suzuki model, we will theoretically calculate the ${\mathrm{\Lambda }}_c^{+}$ FF from charm quark and present our results at leading order perturbative QCD framework. A comparison confirms a good consistency between both approaches. We will also apply the ${\mathrm{\Lambda }}_c^{+}$ FFs to make theoretical predictions for the energy distribution of ${\mathrm{\Lambda }}_c^{+}$ produced through the top quark decay, to be measured at the CERN LHC.

We study inclusive ${\mathrm{\Lambda }}_c^{\pm }$-baryon production in $pp$ collisions in the general-mass variable-flavor-number scheme and compare with data from the LHCb, ALICE, and CMS collaborations. We perform a new fit of the $c\to {\mathrm{\Lambda }}_c^{+}$ fragmentation function combining $e^{+}{e}^{-}$ data from OPAL and Belle. The agreement with LHC data is slightly worse compared with a calculation using an older fragmentation function, and the tension between different determinations of ${\mathrm{\Lambda }}_c^{\pm }$ production cross sections from the LHC experimental collaborations is not resolved. The ratio of data for ${\mathrm{\Lambda }}_c^{+}$-baryon and $D^0$-meson production seems to violate the universality of $c$-quark to $c$-hadron fragmentation.

The $SU(3)$ Yang-Mills matrix model coupled to fundamental fermions is an approximation of quantum chromodynamics (QCD) on a 3-sphere of radius $R$. The spectrum of this matrix model Hamiltonian is estimated using standard variational methods, and is analyzed in the strong coupling limit. By employing a matching prescription to determine the dependence of the Yang-Mills coupling constant $g$ on $R$, we relate the asymptotic values of the energy eigenvalues in the $R\to \infty$ (flat space) limit to the masses of light hadrons. We find that the matrix model estimates the light hadron spectrum fairly accurately, with the light baryon masses falling within 10%, and most light meson masses falling within about 30% of their observed values.

We demonstrate that tailored laser beams provide a powerful means to make quantum vacuum signatures in strong electromagnetic fields accessible in experiment. Typical scenarios aiming at the detection of quantum vacuum nonlinearities at the high-intensity frontier envision the collision of focused laser pulses. The effective interaction of the driving fields mediated by vacuum fluctuations gives rise to signal photons encoding the signature of quantum vacuum nonlinearity. Isolating a small number of signal photons from the large background of the driving laser photons poses a major experimental challenge. The main idea of the present work is to modify the far-field properties of a driving laser beam to exhibit a fieldfree hole in its center, thereby allowing for an essentially backgroundfree measurement of the signal scattered in the forward direction. Our explicit construction makes use of a peculiar far-field/focus duality.

Using the NOvA neutrino detectors, a broad search has been performed for any signal coincident with 28 gravitational wave events detected by the LIGO/Virgo Collaboration between September 2015 and July 2019. For all of these events, NOvA is sensitive to possible arrival of neutrinos and cosmic rays of GeV and higher energies. For five (seven) events in the NOvA Far (Near) Detector, timely public alerts from the LIGO/Virgo Collaboration allowed recording of MeV-scale events. No signal candidates were found.

The lensing at large deflection angles caused by a Schwarzschild black hole for the case of a nonminimal coupling between gravitation and electromagnetism is examined. We show that photons follow an effective geometry, which displays an effective photon sphere. For the case in which the source, lens and observer are aligned, so that relativistic Einstein rings are formed, the dependence of the angular separation $\delta \theta$ between the first and second ring with the relevant coupling parameter is calculated. We argue that such a separation, which may be measured by telescopes that will be operative in the near future, may set an upper and a lower limit for the coupling parameter.