Here, we extend previous work on efficiency corrections for cumulant measurements Bzdak and Koch, Phys. Rev. C 86, 044904 (2012)PRVCAN0556-281310.1103/PhysRevC.86.044904; Phys. Rev. C 91, 027901 ...(2015)PRVCAN0556-281310.1103/PhysRevC.91.027901. We will then discuss the limitations of the methods presented in these papers. Specifically we will consider multiplicity dependent efficiencies as well as nonbinomial efficiency distributions. We will discuss the most simple and straightforward methods to implement those corrections.
Recent findings link fronto-temporal gamma electroencephalographic (EEG) activity to conscious awareness in dreams, but a causal relationship has not yet been established. We found that current ...stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Other stimulation frequencies were not effective, suggesting that higher order consciousness is indeed related to synchronous oscillations around 25 and 40 Hz.
This report summarizes the presentations and discussions during the Rapid Reaction Task Force “Dynamics of critical fluctuations: Theory – phenomenology – heavy-ion collisions”, which was organized ...by the ExtreMe Matter Institute EMMI and held at GSI, Darmstadt, Germany in April 2019. We address the current understanding of the dynamics of critical fluctuations in QCD and their measurement in heavy-ion collision experiments. In addition, we outline what might be learned from studying correlations in other physical systems, such as cold atomic gases.
Transcranial alternating-current stimulation (tACS) in the frequency range of 1-100 Hz has come to be used routinely in electroencephalogram (EEG) studies of brain function through entrainment of ...neuronal oscillations. It turned out, however, to be highly non-trivial to remove the strong stimulation signal, including its harmonic and non-harmonic distortions, as well as various induced higher-order artifacts from the EEG data recorded during the stimulation. In this paper, we discuss some of the problems encountered and present methodological approaches aimed at overcoming them. To illustrate the mechanisms of artifact induction and the proposed removal strategies, we use data obtained with the help of a schematic demonstrator setup as well as human-subject data.
We develop an innovative and unbiased procedure, based on event mixing, to account for unavoidable contributions from volume (or system size) fluctuations to experimentally measured moments of ...particle multiplicity distributions produced in relativistic nuclear collisions. Within the wounded-nucleon model they are characterized by fluctuations of the number of wounded nucleons, the latter usually referred to as participants. For the first time we extract participant fluctuations directly from the data used for the fluctuation analysis, i.e., without involving model calculations. To achieve this we constructed a dedicated event-mixing algorithm that eliminates all possible correlations between produced particles while preserving the volume fluctuations. The procedure provides direct access to the cumulants of wounded-nucleon distributions, which can be used to account for non-critical contributions to the experimentally measured cumulants of multiplicity distributions.
bosons, or so-called "dark photons," are one of the possible candidates for the dark matter mediators. They are supposed to interact with the standard matter via a "vector portal" due to the U(1) − ...U(1)' symmetry group mixing which might make them visible in particle and heavy-ion experiments. While there is no confirmed observation of dark photons, the detailed analysis of different experimental data allows to estimate the upper limit for the kinetic mixing parameter ε2 depending on the mass MU of U bosons which is also unknown. In this study we present theoretical constraints on the upper limit of ε2 (MU) in the mass range MU ≤ 0.6 GeV from the comparison of the calculated dilepton spectra with the experimental data from the HADES collaboration at SIS18 energies where the dark photons are not observed. Our analysis is based on the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach which reproduces well the measured dilepton spectra in p + p, p + A and A + A collisions. Additionally to the different dilepton channels originating from interactions and decays of ordinary matter particles (mesons and baryons), we incorporate the decay of hypothetical U bosons to dileptons, U → e+e−, where the U bosons themselves are produced by the Dalitz decay of pions π0 → γU, η mesons η → γU and Delta resonances Δ → NU. Our analysis can help to estimate the requested accuracy for future experimental searches of "light" dark photons by dilepton experiments.
The goal of the study was to seek physiological correlates of lucid dreaming. Lucid dreaming is a dissociated state with aspects of waking and dreaming combined in a way so as to suggest a specific ...alteration in brain physiology for which we now present preliminary but intriguing evidence. We show that the unusual combination of hallucinatory dream activity and wake-like reflective awareness and agentive control experienced in lucid dreams is paralleled by significant changes in electrophysiology.
19-channel EEG was recorded on up to 5 nights for each participant. Lucid episodes occurred as a result of pre-sleep autosuggestion.
Sleep laboratory of the Neurological Clinic, Frankfurt University.
Six student volunteers who had been trained to become lucid and to signal lucidity through a pattern of horizontal eye movements.
Results show lucid dreaming to have REM-like power in frequency bands delta and theta, and higher-than-REM activity in the gamma band, the between-states-difference peaking around 40 Hz. Power in the 40 Hz band is strongest in the frontal and frontolateral region. Overall coherence levels are similar in waking and lucid dreaming and significantly higher than in REM sleep, throughout the entire frequency spectrum analyzed. Regarding specific frequency bands, waking is characterized by high coherence in alpha, and lucid dreaming by increased delta and theta band coherence. In lucid dreaming, coherence is largest in frontolateral and frontal areas.
Our data show that lucid dreaming constitutes a hybrid state of consciousness with definable and measurable differences from waking and from REM sleep, particularly in frontal areas.
Search for dark photons in heavy‐ion collisions Bratkovskaya, Elena; Schmidt, Ida; Gumberidze, Malgorzata ...
Astronomische Nachrichten,
January-February 2023, 2023-01-00, 20230101, Volume:
344, Issue:
1-2
Journal Article
Peer reviewed
Open access
The vector U‐bosons, or so‐called “dark photons,” are one of the possible candidates for the dark matter mediators. They are supposed to interact with the standard matter via a “vector portal” due to ...the U(1)−U(1)′$$ U(1)-U{(1)}^{\prime } $$ symmetry group mixing which might make them visible in particle and heavy‐ion experiments. While there is no confirmed observation of dark photons, the detailed analysis of different experimental data allows us to estimate the upper limit for the kinetic mixing parameter ϵ2$$ {\epsilon}^2 $$ depending on the mass MU$$ {M}_U $$ of U‐bosons which is also unknown. We have introduced a procedure to define theoretical constraints on the upper limit of ϵ2MU$$ {\epsilon}^2\left({M}_U\right) $$ from heavy‐ion (as well as p + p and p+A$$ p+A $$) dilepton data. Our analysis is based on the microscopic Parton‐Hadron‐String Dynamics transport approach where we incorporated the decay of hypothetical U‐bosons to dileptons, U→e+e−$$ U\to {e}^{+}{e}^{-} $$, where the U‐bosons themselves are produced by the Dalitz decay of pions π0→γU$$ {\pi}^0\to \gamma U $$, η‐mesons η→γU$$ \eta \to \gamma U $$, and Delta resonances Δ→NU$$ \Delta \to NU $$. The extension of our procedure to other dark matter candidates is foreseen.
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