Using the DØ detector, we have studied events produced in p̄p collisions that contain large forward regions with very little energy deposition (“rapidity gaps”) and concurrent jet production at ...center-of-mass energies of s=630 and 1800 GeV. The fraction of events with forward or central jets associated with rapidity gaps is compared to predictions for hard diffraction. We also extract the momentum loss for scattered protons in such processes.
We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies ...and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter \(\epsilon_{\mu \tau}\). The best-fit value is consistent with no NSI at a p-value of 25.2%. With a 90% confidence interval of \(-0.0041 \leq \epsilon_{\mu \tau} \leq 0.0031\) along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.
Search for the decay b→ Xsμ+μ Abolins, M.; Acharya, B.S.; Adams, M. ...
Physics letters. B,
03/1998, Volume:
423, Issue:
3
Journal Article
Peer reviewed
We have searched for the flavor-changing neutral current decay
b→
X
s
μ
+
μ
− in
p
p
̄
collisions at
s
=
1.8 TeV with the DØ detector at Fermilab. We determine the 90% confidence level limit for the ...branching fraction to be
B(
b→
X
s
μ
+
μ
−) < 3.2×10
−4. We argue that this limit is more stringent than the best published limit on this decay rate.
Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the ...South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allows IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100 GeV and several TeV in the muon neutrino charged current channel. No significant clustering of neutrinos above background expectation was observed in four years of data recorded with the completed IceCube detector. Upper limits on the neutrino flux for a number of spectral hypotheses are reported for a list of astrophysical objects in the southern hemisphere.
We present measurements of the
b
b
production cross section and angular correlations using the DØ detector at the Fermilab Tevatron
p
p
Collider operating at
s
= 1.8 TeV. The
b quark production cross ...section for
|y
b|
<
1.0
and
p
T
b
>
6
GeV/
c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading order QCD calculation of heavy flavor production but are greater than the central values of these predictions. The angular correlations between
b and
b
quarks, measured from the azimuthal opening angle between their decay muons, also agree in shape with the next-to-leading order QCD prediction.
PDF
