This is going to be for the past several days, and as such it will be a little denser (and a little lighter, at random) than I would like…but here goes:
So I grabbed this one primarily for the “Pixie-like experiments” bit on the end of the title. To expand on this some, Pixie (The Primordial Inflation Explorer) is a “nulling polarimeter” for CMB observations. Effectively, its goal is to measure the gravitational wave signature of primordial inflation using the imprint of linear polarization on the CMB. The paper I found proposing the experiment was dated May 2011, but I’m not sure what progress has been made on the launch and usage of said device. If you’re wondering what the hell Fisher Matrices are [I was] wiki links you to “Fisher Information” and gives that as: “is the variance of the score, or the expected value of the observed information.” Informally, this is the amount of information an observable random variable contains about an unknown parameter which the probability of said variable depends on [wording borrowed heavily from here. On last thing, I was too lazy to look into “Silk Damping” but that is a great name for a thing. Note: The Polar Ionospheric X-ray Imaging Experiment (PIXIE), is a completely different Lockheed project.
It is most definitely a good thing that even with our naive measurements of the “Higgs-like” particle we can over-constrain the SM and we get many predictions in excess precision of our measurements (W mass and weak mixing angle). S, T, U parameters, huh? Apparently these “oblique parameters” are lower order observables which quantify deviations from the SM. There are higher-order extensions called V,W, and X as well. I’d like to note that the authors find “no direct signs of new physics” which is a blessing, and a curse. Might be worth looking at what they have to say at the end of the paper about what the ILC would best shine light on.
This paper basically makes the case its title states. Beta functions are a pretty general family of PDFs definite by two parameters, alpha and beta. Basically, they find that a beta distribution fits the distribution of eccentricity much better than the (traditional?) “next best” model of a Rayleigh + Exponential distribution. Kind of worth noting: Beta distributions are uniquely determined over their domain…not surprising, but good to know. Also, they got an 11.6 sigma confidence that “short-” and “long-” period planets are described by distinct Beta distributions. Unfortunately, I don’t have time to look into this distinction, but that is a massive confidence so I find the result surprising.
So Halo Mass Functions (HMF), I believe, are literally the number of a given Halo Mass observed, often with a curve for each redshift. LCDM models constrain Omega_M and in turn constrain the actual HMF. The author’s note that the normalization (Sigma_8 ?) has a strong impact on the high mass region of the HMF and our poorer limits on this parameter produce subsequently limited HMF constraints. Cool to note: The HMF measurements are close to the “scatter” in HMF fitting functions…so Cosmology is at a point where they need ~’NLO’~ calculations of theoretical HMFs in different models; at least, that’s how I interpreted the situation.
I don’t have much to say about this other than that I’m still surprised that people study Asteroseismology. Not only that, it’s cool that there’s interesting mathematical physics (asymptotic theory) associated with the field. The long story short with this paper is that more careful analysis showed they weren’t too far off in the first place 😛
So, I thought this might be a bit fringe/quacky reading over the abstract the first time…but I think I was wrong. Chameleon is a *great* name for a thing, and I’m glad we have more things with cool names in science. More seriously, this field theory represents and odd but interesting idea, that the mass of a particle could be coupled to the ambient matter density. These self-interacting fields do weird things and have a “rich phenomenology” as the author states. Fortunately and Unfortunately, we know a few important things about them: they can’t account for the observed cosmic acceleration and they’re almost within reach experimentally. Probably a dud, but a cool one!
As opposed to my preferred theory of DM (see here), the authors here propose a strong dynamics which might bind together dark matter and examine how it would relate to QCD. Supposedly, the can explain the baryon / dark baryon asymmetries in this manner. I have not read this paper yet, but I am interested in their questionable claims. Naturally, they consider a subset of particles which interact under both “QCDs” and I’m curious how this might work. Something I might keep track of, for sure.
So I only have one thing to say about this paper: it looks like useful but boring shit. Excuse me, two things: it looks like it was an undergraduate project. I’m not implying that undergraduates don’t produce useful things or anything silly like that, I’m just surprised this got published. The abstract outlines what they did and it seemed kind of, well, trivial? I’m sure it took some time…but I feel like it was just a series of standard, boring calculations one after the next. 😐 color me unimpressed. Note: I think I’m right, given the lack of affiliation on the second author. Totally could have been an REU project.
This was sort of a surprise. It’s actually a paper from the 1979 Supergravity workshop…so it’s not exactly new, but I would really like to look into this. Outdated and probably not a good direction for research, but looking at families of symmetries isn’t necessarily a bad thing.
Totally grabbed this one since I’ve met some people on it, will read for Cosmic Coffee.
While we think we have the Higgs, we don’t know much about it and I think it’s a good thing that CMS has put out a detailed review on the state of our Higgs searches with mass 145 GeV and upwards. The additional exclusion (up to 710 GeV at 95% CL) isn’t anything terribly exciting, but it’s nice to see.
I thought we’d solved this problem already? Well, apparently the author found the approaches in the literature prove to be invalid and that we are missing solutions. May want to look into this later to sort out exactly what they’re claiming.
That’s the majority of the stuff, for now.
Unfortunately my feeds are such that I’ll probably have a several day old paper in my next post….oh well.