State of Fear Revisited

Cooling the Warming Debate

See:

• The State of Fear

See Also:

•  ICARUS Proves Neutrinos At Least 10 Times Faster Than Light

• Getting Science Through: Misunderstood Terms In Science Communication

The Eternally Existing, Self-Reproducing, Frequently Puzzling Inflationary Universe

The Eternally Existing, Self-Reproducing, Frequently Puzzling Inflationary Universe

Since I cannot comment at Sean's Blog either,  I might as well comment here too:)

27.   Moshe Says:
October 23rd, 2011 at 5:00 am

Igor, I am not sure I understand. We have an initial value problem, so today’s observations are determined once you specify an initial state at some time in the distant past. If you specify the time to be the beginning of the big bang evolution, with the correct but very contrived initial state (nearly homogeneous with just the right kind of fluctuations) then you get no conflict with observation. By contruction, same applies to inflation, because it reproduces that initial state and all subsequent evolution. The only point of inflation is to make that initial state the outcome of prior evolution. By construction all current observations will then be identical, but the initial state will be more natural and less contrived. As I understand Sean’s statement, quantifying this intuitive notion of naturalness is tricky, and it is not always clear inflation indeed comes ahead. I hope I am not mangling things…

And, for the record, in my mind the notion of “naturalness” is one instance of “algorithmic compression”, which is the whole point of seeking a scientific explanation. Without invoking such criteria, by definition (for example) the particle data group review book would be always the best “theory” of particle physics, and you’d never need to learn about gauge theories and spontaneous symmetry breaking and all that stuff.

See Also:

Why Penrose is one of many crackpots when it comes to inflation

CMS Physics Results

Link on Title.

• All CMS public results can be found in CDS , and are categorized by subject (group) in this page.
• Publications and preprints on collision data, ordered by time, are available at this link.
• Publications on cosmic-ray data can be found here; the paper on muon charge ratio is available here .
• The complete list of publications is here.
• Preliminary results on collision data at 0.9, 2.36 and 7 TeV are described in Physics Analysis Summaries; Monte Carlo studies can be found here.
• Public performance plots are shown in Detector Performance Summaries.

See Also:CMS Physics Analysis Summaries

What is a Higgs Boson? Lepton fizz?

Fermilab scientist Don Lincoln describes the nature of the Higgs boson. Several large experimental groups are hot on the trail of this elusive subatomic particle which is thought to explain the origins of particle mass

See:Why does anything have substance? Hunting the Higgs boson

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 A search for excited leptons in pp collisions at ps = 7 TeV

 

A search for excited leptons is carried out with the CMS detector at the LHC, using
36 pb��1 of pp collision data recorded at ps = 7 TeV. The search is performed for associated
production of a lepton and an oppositely charged excited lepton pp ! `` ,
followed by the decay ` ! `g, resulting in the ``g final state, where ` = e, m. No
excess of events above the standard model expectation is observed. Interpreting the
findings in the context of ` production through four-fermion contact interactions and
subsequent decay via electroweak processes, first upper limits are reported for ` production
at this collision energy. The exclusion region in the compositeness scale L and
excited lepton mass M` parameter space is extended beyond previously established
limits. For L = M` , excited lepton masses are excluded below 1070 GeV/c2 for e
and 1090 GeV/c2 for m at the 95% confidence level.
See Also : Lepton fizz

Aaron O'Connell: Making sense of a visible quantum object

And so that's what we did. We turned off the lights, and then we put it in a vacuum and sucked out all the air, and then we cooled it down to just a fraction of a degree above absolute zero. Now, all alone in the elevator, the little chunk of metal is free to act however it wanted. And so we measured its motion. We found it was moving in really weird ways. Instead of just sitting perfectly still, it was vibrating. And the way it was vibrating was breathing something like this -- like expanding and contracting bellows. And by giving it a gentle nudge, we were able to make it both vibrate and not vibrate at the same time -- something that's only allowed with quantum mechanics.

Aspera

Home Site Located in Title

A European Network For Astroparticle Physics in Europe

ASPERA is a network of national government agencies responsible for coordinating and funding national research efforts in Astroparticle Physics

• Hunting neutrinos...

• The IceCube experiment

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See Also: LAGUNA large neutrino observatory design moves forward

The Chicagoland Observatory for Underground Particle Physics (COUPP)

The Chicagoland Observatory for Underground Particle Physics (COUPP) collaboration looks for bubbles in chambers filled with a compound containing carbon, fluorine and iodine. The fluid is superheated beyond the boiling point but has no rough surface to form bubbles. When a specific type of particle interacts in the chamber, it can deposit enough energy to boil the fluid and make a bubble. Electrons do not produce bubbles, while a dark matter particle interacting with a nucleus can – making this the key for dark matter detection. See:Bubble chamber gets more precise in dark matter search

Bold added for emphasis.

See Also: Bubble chamber gets more precise in dark matter search

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The accelerating universe is the observation that the universe appears to be expanding at an increasing rate, which in formal terms means that the cosmic scale factor a(t) has a positive second derivative,^[1] implying that the velocity at which a given galaxy is receding from us should be continually increasing over time^[2] (here the recession velocity is the same one that appears in Hubble's law; defining 'velocity' in cosmology is somewhat subtle, see Comoving distance#Uses of the proper distance for a discussion). In 1998, observations of type Ia supernovae suggested that the expansion of the universe has been accelerating^[3][4] since around redshift of z~0.5.^[5] The 2006 Shaw Prize in Astronomy and the 2011 Nobel Prize in Physics were both awarded to Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess for the 1998 discovery of the accelerating expansion of the Universe through observations of distant supernovae.^[6][7]

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In cosmology, baryon acoustic oscillations (BAO) refers to an overdensity or clustering of baryonic matter at certain length scales due to acoustic waves which propagated in the early universe.^[1] In the same way that supernova experiments provide a "standard candle" for astronomical observations,^[2] BAO matter clustering provides a "standard ruler" for length scale in cosmology.^[1] The length of this standard ruler (~150 Mpc in today's universe^[3]) can be measured by looking at the large scale structure of matter using astronomical surveys.^[3] BAO measurements help cosmologists understand more about the nature of dark energy (the acceleration of the universe) by constraining cosmological parameters.^[1]

***

SDSS III: 2008-2014

In mid-2008, SDSS-III was started. It comprises four separate surveys, each conducted on the same 2.5m telescope: ^[9][10]

• Apache Point Observatory Galactic Evolution Experiment (APOGEE)
• Baryon Oscillation Spectroscopic Survey (BOSS)
• Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS)^[11]
• Sloan Extension for Galactic Understanding and Exploration 2 (SEGUE-2)

Baryon Oscillation Spectroscopic Survey (BOSS)

The SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS) will map the spatial distribution of luminous red galaxies (LRGs) and quasars to detect the characteristic scale imprinted by baryon acoustic oscillations in the early universe. Sound waves that propagate in the early universe, like spreading ripples in a pond, imprint a characteristic scale on the positions of galaxies relative to each other ^[12] .

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See Also:

• SuperCDMS An Improvement on Detection 
• There Be Dragons on the Dark Matter Issue? 
• Sounding Off on the Dark Matter Issue
  

Particles that can hit the Earth's atmosphere at high speeds.

Source: University of Chicago Library

Enrico Fermi's notebook of December 1948 contains four pages that represent the genesis of his theory of cosmic rays, particles that can hit the Earth's atmosphere at high speeds. In these pages, he worked out the acceleration of cosmic rays due to a series of collisions with magnetic clouds moving through the universe, a process later named Fermi acceleration.SEE:Archive: Logbook

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History of Cosmic Rays

• Introduction to Cosmic Rays
• Ultra-High Energy Cosmic Rays
• Detection of UHE Cosmic Rays
• History of the Air Fluorescence Technique
• The Fly's Eye (1981-1993)

Photos: CERN - A tour of the large hadron collider

Photos: CERN - A tour of the large hadron collider

Jets in a Medium

[Picture credit: Thorsten Renk, Slide 17 of this presentention]

Centrality Dependance

See: AdS/CFT confronts data