Search results for "Astrophysical Phenomena"
showing 10 items of 4943 documents
Probing secret interactions of eV-scale sterile neutrinos with the diffuse supernova neutrino background
2020
Sterile neutrinos with mass in the eV-scale and large mixings of order $\theta_0\simeq 0.1$ could explain some anomalies found in short-baseline neutrino oscillation data. Here, we revisit a neutrino portal scenario in which eV-scale sterile neutrinos have self-interactions via a new gauge vector boson $\phi$. Their production in the early Universe via mixing with active neutrinos can be suppressed by the induced effective potential in the sterile sector. We study how different cosmological observations can constrain this model, in terms of the mass of the new gauge boson, $M_\phi$, and its coupling to sterile neutrinos, $g_s$. Then, we explore how to probe part of the allowed parameter spa…
BVRI photometry of high-mass X-ray binaries
2015
We present photometric observations of the field around the optical counterparts of high-mass X-ray binaries. Our aim is to study the long-term photometric variability in correlation with their X-ray activity and derive a set of secondary standard stars that can be used for time series analysis. We find that the donors in Be/X-ray binaries exhibit larger amplitude changes in the magnitudes and colours than those hosting a supergiant companion. The amplitude of variability increases with wavelength in Be/X-ray binaries and remains fairly constant in supergiant systems. When time scales of years are considered, a good correlation between the X-ray and optical variability is observed. The X-ra…
"Differential diphoton $|cos(\theta*)|$" of "Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$^{-1}$ of Pb+Pb…
2020
Measured differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for diphoton $|cos(\theta*)|$ are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line) with bands denoting the theoretical uncertainty.
"Differential diphoton invariant mass" of "Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$^{-1}$ of Pb+Pb d…
2020
Measured differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for diphoton invariant mass are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line) with bands denoting the theoretical uncertainty.
"Differential average photon transverse momentum" of "Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$^{-1}$…
2020
Measured normalised differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for average photon transverse momentum are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line) with bands denoting the theoretical uncertainty.
"Differential normalised diphoton rapidity" of "Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$^{-1}$ of Pb…
2020
Measured normalised differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for diphoton rapidity are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line).
"Differential normalised average photon transverse momentum" of "Measurement of light-by-light scattering and search for axion-like particles with 2.…
2020
Measured normalised differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for average photon transverse momentum are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line).
"The 95% CL upper limit on the ALP coupling $1/\Lambda_{a}$" of "Measurement of light-by-light scattering and search for axion-like particles with 2.…
2020
The 95% CL upper limit on the ALP coupling $1/\Lambda_{a}$ for the $\gamma\gamma\rightarrow a \rightarrow \gamma\gamma$ process as a function of ALP mass m$_{a}$. The observed upper limit is shown as a solid black line and the expected upper limit is shown by the dashed black line with its $\pm1$ and $\pm2$ standard deviation bands. The discontinuity at $m_{a} = 70 GeV$ is caused by the increase of the mass-bin width which brings an increase in signal acceptance.
"Differential normalised diphoton $|cos(\theta*)|$" of "Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$^{-1…
2020
Measured normalised differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for diphoton $|cos(\theta*)|$ are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line).
"Differential diphoton rapidity" of "Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$^{-1}$ of Pb+Pb data wi…
2020
Measured differential fiducial cross sections of $\gamma\gamma \rightarrow \gamma\gamma$ production in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for diphoton rapidity are shown as points with error bars giving the statistical uncertainty and grey bands indicating the size of the total uncertainty. The results are compared with the prediction from the SuperChic v3.0 MC generator (solid line) with bands denoting the theoretical uncertainty.