nucl-th digest · Jul 29, 2016

[Submitted on 27 Jul 2016] (cross-list from hep-ph)

IC at IC: IceCube can constrain the intrinsic charm of the proton

The discovery of extraterrestrial neutrinos in the $\sim$ 30 TeV -- PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic-ray particles interacting in the Earth's atmosphere. It is conventional to use the calculations of charm hadroproduction using gluon splitting $g \to c c ˉ$ alone. However, QCD predicts an additional "intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton's valence quarks. We estimate the prompt neutrino spectrum due to intrinsic charm. We find that the atmospheric prompt neutrino flux from intrinsic charm is comparable to those calculated using QCD computations not including intrinsic charm, once we normalize the intrinsic charm differential cross sections to the ISR and the LEBC-MPS collaboration data. In future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major questions in high energy physics phenomenology.

Comments:: v3: 13 pages, 4 figures. Added more details about the calculation. Conclusions unchanged. Accepted in PRD
Subjects:: High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:: 1607.08240 [pdf]

PRD(2017)·54 citations

Kinematic sensitivity to the Fierz term of

β

-decay differential spectra

The current most stringent constraints on exotic scalar or tensor couplings in neutron and nuclear

β

decay, involving left-handed neutrinos, are obtained from the Fierz interference term. The sensitivity to this term in a correlation coefficient is usually driven by an energy-averaged kinematic factor that increases monotonically toward smaller values of the

β

endpoint energies. We first point out here that this property does not hold for certain differential observables that are directly sensitive to the Fierz term, such as the

β

or the recoil energy spectrum. This observation is relevant for the selection of sensitive transitions in searches for exotic couplings through spectrum shape measurements. We then point out previous errors in the exploitation of measurements of the

β - ν

angular correlation coefficient and discuss their impact on the extraction of constraints on exotic couplings.

Comments:: 7 pages, 5 figures
Subjects:: Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:: 1607.08347 [pdf]

PRC(2016)·44 citations

Friday·July 29, 2016

IC at IC: IceCube can constrain the intrinsic charm of the proton

Kinematic sensitivity to the Fierz term of $β$ -decay differential spectra

Affiliations

IC at IC: IceCube can constrain the intrinsic charm of the proton

Kinematic sensitivity to the Fierz term of β-decay differential spectra

Affiliations

Kinematic sensitivity to the Fierz term of $β$ -decay differential spectra