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B. Hoeneisen

Publications and source records attributed to B. Hoeneisen.

At least 19 recordsLinked to original sources
arXiv2018

Measurements of the cosmological parameters $Ω_m$, $Ω_k$, $Ω_\textrm{de}(a)$, $H_0$, and $\sum m_ν$

From Baryon Acoustic Oscillation measurements with Sloan Digital Sky Survey SDSS DR14 galaxies, and the acoustic horizon angle $θ_*$ measured by the Planck Collaboration, we obtain $Ω_m = 0.2724 \pm 0.0047$, and $h + 0.020 \cdot \sum{m_ν} = 0.7038 \pm 0.0060$, assuming flat space and a cosmological constant. We combine this result with the 2018 Planck `TT,TE,EE$+$lowE$+$lensing' analysis, and update a study of $\sum m_ν$ with new direct measurements of $σ_8$, and obtain $\sum m_ν= 0.27 \pm 0.08$ eV assuming three nearly degenerate neutrino eigenstates. Measurements are consistent with $Ω_k = 0$, and $Ω_\textrm{de}(a) = Ω_Λ$ constant.

astro-ph.CO↗
arXiv2017

Constraints on neutrino masses from Baryon Acoustic Oscillation measurements

From 21 independent Baryon Acoustic Oscillation (BAO) measurements we obtain the following sum of masses of active Dirac or Majorana neutrinos: $\sum m_ν= 0.711 - 0.335 \cdot δh + 0.050 \cdot δb \pm 0.063 \textrm{ eV,}$ where $δh \equiv (h - 0.678) / 0.009$ and $δb \equiv (Ω_b h^2 - 0.02226) / 0.00023$. This result may be combined with independent measurements that constrain the parameters $\sum m_ν$, $h$, and $Ω_b h^2$. For $δh = \pm 1$ and $δb = \pm 1$, we obtain $m_ν< 0.43$ eV at 95\% confidence.

hep-ph↗
arXiv2016

Study of baryon acoustic oscillations with SDSS DR13 data and measurements of $Ω_k$ and $Ω_\textrm{DE}(a)$

We measure the baryon acoustic oscillation (BAO) observables $\hat{d}_α(z, z_c)$, $\hat{d}_z(z, z_c)$, and $\hat{d}_/(z, z_c)$ as a function of redshift $z$ in the range 0.1 to 0.7 with Sloan Digital Sky Survey (SDSS) data release DR13. These observables are independent and satisfy a consistency relation that provides discrimination against miss-fits due to background fluctuations. From these measurements and the correlation angle $θ_\textrm{MC}$ of fluctuations of the Cosmic Microwave Background (CMB) we obtain $Ω_k = -0.015 \pm 0.030$, $Ω_{\textrm{DE}} + 2.2 Ω_k = 0.717 \pm 0.004$ and $w_1 = 0.37 \pm 0.61$ for dark energy density allowed to vary as $Ω_{\textrm{DE}}(a) = Ω_{\textrm{DE}} [ 1 + w_1 ( 1 - a)]$. We present measurements of $Ω_{\textrm{DE}}(a)$ at six values of the expansion parameter $a$. Fits with several scenarios and data sets are presented. The data is consistent with space curvature parameter $Ω_k = 0$ and $Ω_{\textrm{DE}}(a)$ constant.

astro-ph.CO↗
arXiv2016

Study of baryon acoustic oscillations with SDSS DR12 data and measurements of $Ω_k$ and $Ω_\textrm{DE}(a)$. Part II

We define Baryon Acoustic Oscillation (BAO) observables $\hat{d}_α(z, z_c)$, $\hat{d}_z(z, z_c)$, and $\hat{d}_/(z, z_c)$ that do not depend on any cosmological parameter. From each of these observables we recover the BAO correlation length $d_\textrm{BAO}$ with its respective dependence on cosmological parameters. These BAO observables are measured as a function of redshift $z$ with the Sloan Digital Sky Survey (SDSS) data release DR12. From the BAO measurements alone, or together with the correlation angle $θ_\textrm{MC}$ of the Cosmic Microwave Background (CMB), we constrain the curvature parameter $Ω_k$ and the dark energy density $Ω_\textrm{DE}(a)$ as a function of the expansion parameter $a$ in several scenarios. These observables are further constrained with external measurements of $h$ and $Ω_\textrm{b} h^2$. We find some tension between the data and a cosmology with flat space and constant dark energy density $Ω_\textrm{DE}(a)$.

astro-ph.CO↗
arXiv2016

Study of baryon acoustic oscillations with SDSS DR12 data and measurement of $Ω_\textrm{DE}(a)$

We define Baryon Acoustic Oscillation (BAO) distances $\hat{d}_α(z, z_c)$, $\hat{d}_z(z, z_c)$, and $\hat{d}_/(z, z_c)$ that do not depend on cosmological parameters. These BAO distances are measured as a function of redshift $z$ with the Sloan Digital Sky Survey (SDSS) data release DR12. From these BAO distances alone, or together with the correlation angle $θ_\textrm{MC}$ of the Cosmic Microwave Background (CMB), we constrain the cosmological parameters in several scenarios. We find $4.3 σ$ tension between the BAO plus $θ_\textrm{MC}$ data and a cosmology with flat space and constant dark energy density $Ω_\textrm{DE}(a)$. Releasing one and/or the other of these constraints obtains agreement with the data. We measure $Ω_\textrm{DE}(a)$ as a function of $a$.

astro-ph.CO↗
arXiv2016

Ratio between two $Λ$ and $\barΛ$ production mechanisms in $p$ scattering

We consider $Λ$ and $\barΛ$ production in a wide range of proton scattering experiments. The produced $Λ$ and $\barΛ$ may or may not contain a diquark remnant of the beam proton. The ratio of these two production mechanisms is found to be a simple universal function $r = [ κ/(y_p - y) ]^i$ of the rapidity difference $y_p - y$ of the beam proton and the produced $Λ$ or $\barΛ$, valid over four orders of magnitude, from $r \approx 0.01$ to $r \approx 100$, with $κ= 2.86 \pm 0.03 \pm 0.07$, and $i = 4.39 \pm 0.06 \pm 0.15$.

hep-ph↗
arXiv2015

Trying to understand dark matter

We present some "back-of-the-envelope" calculations to try to understand cold dark matter, its searches, and extensions of the Standard Model. Some of the insights obtained from this exercise may be useful.

physics.gen-ph↗
arXiv2014

Anomalous dimuon charge asymmetry in proton-antiproton collisions

We present an overview of the measurements of the like-sign dimuon charge asymmetry by the DO Collaboration at the Fermilab Tevatron proton-antiproton Collider. The results differ from the Standard Model prediction of CP violation in mixing and interference of B^0 and B^0_s by 3.6 standard deviations.

hep-ex↗
arXiv2013

Understanding the like-sign dimuon charge asymmetry in $p \bar{p}$ collisions

The DØ collaboration has measured the like-sign dimuon charge asymmetry in $p \bar{p}$ collisions at the Fermilab Tevatron collider. The result is significantly different from the standard model expectation of CP violation in mixing. In this paper we consider the possible causes of this asymmetry and identify one standard model source not considered before. It decreases the discrepancy of the like-sign dimuon charge asymmetry with the standard model prediction, although does not eliminate it completely.

hep-ex↗
arXiv2006

Trying to understand mass

We try to understand how particles acquire mass in general, and in particular, how they acquire mass in the standard model and beyond.

hep-th↗
arXiv2005

Built to evolve

We study the probabilities of evolution based on random mutations and natural selection. We conclude that evolution to multicellular eukaryots, or even prokaryots, is unlikely to be the result of only random mutations. Complex organisms have evolved through several mechanisms besides random mutations, namely DNA recombination, adaptive mutations, and acquisition of foreign DNA. We conclude that all living organisms, in addition to being self-organizing and reproducing (autopoyetic), have built-in mechanisms of evolution, some of which respond in very specific ways to environmental stress.

q-bio.PE↗
arXiv2005

Global Warming: some back-of-the-envelope calculations

We do several simple calculations and measurements in an effort to gain understanding of global warming and the carbon cycle. Some conclusions are interesting: (i) There has been global warming since the end of the "little ice age" around 1700. There is no statistically significant evidence of acceleration of global warming since 1940. (ii) The increase of CO_2 in the atmosphere, beginning around 1940, accurately tracks the burning of fossil fuels. Burning all of the remaining economically viable reserves of oil, gas and coal over the next 150 years or so will approximately double the pre-industrial atmospheric concentration of CO_2. The corresponding increase in the average temperature, due to the greenhouse effect, is quite uncertain: between 1.3 and 4.8K. This increase of temperature is (partially?) offset by the increase of aerosols and deforestation. (iii) Ice core samples indicate that the pre-historic CO_2 concentration and temperature are well correlated. We conclude that changes in the temperatures of the oceans are probably the cause of the changes of pre-historic atmospheric CO_2 concentration. (iv) Data suggests that large volcanic explosions can trigger transitions from glacial to interglacial climates. (v) Most of the carbon fixed by photosynthesis in the Amazon basin returns to the atmosphere due to aerobic decay.

physics.ao-ph↗
arXiv2004

A toy model of the brain

We have designed a toy brain and have written computer code that simulates it. This toy brain is flexible, modular, has hierarchical learning and recognition, has short and long term memory, is distributed (i.e. has no central control), is asynchronous, and includes parallel and series processing. We have simulated the neurons calculating their internal voltages as a function of time. We include in the simulation the ion pumps of the neurons, the synapses with glutamate or GABA neurotransmitters, and the delays of the action pulses in axons and dendrites. We have used known or plausible circuits of real brains. The toy brain reads books and learns languages using the Hebb mechanism. Finally, we have related the toy brain with what might be occurring in a real brain.

q-bio.NC↗
arXiv2002

What future does the universe have?

We discuss the future evolution of the universe in the light of recent observations. The apparent luminosity vs. redshift of supernovae favor an accelerating universe. However an Einstein-de Sitter critical universe should not be ruled out yet.

astro-ph↗