A Beautiful New Spectroscopy Measurement

by Tommaso Dorigo

What is spectroscopy ?

(A) the observation of ghosts by infrared visors or other optical devices

(B) the study of excited states of matter through observation of energy emissions

If you answered (A), you are probably using a lousy internet search engine; and btw, you are rather dumb. Ghosts do not exist.

Otherwise you are welcome to read on. We are, in fact, about to discuss a cutting-edge spectroscopy measurement, performed by the CMS experiment using lots of proton-proton collisions by the CERN Large Hadron Collider (LHC).

Is Dark Matter Lurking in Neutron Decays?

by Tommaso Dorigo

A paper by B. Fornal and B. Grinstein published last week in Physical Review Letters is drawing a lot of interest to one of the most well-known pieces of subnuclear physics since the days of Enrico Fermi: beta decay.

The mechanism by means of which a neutron transmutes into a proton has been studied for decades before the neutron was officially discovered (by Chadwick, in 1932). That is because beta decay is at the heart of radioactive processes: nuclei of elements rich with neutrons can turn into others by turning one of their neutrons into a proton, with the emission of an electron and an antineutrino. The details of that reaction were understood thanks to Fermi and a handful of other

Train-time/test-time data augmentation

by Giles Strong

The week before last I was presenting an update of some of my analysis work to the rest of my group. The work involved developing a neural-network to classify particle-collisions at the LHC.

Higgs Hacking

by Giles Strong

A few days before I returned from CERN at the beginning of the month, I attended a talk on the upcoming TrackML challenge. This is a competition beginning this month in which members of the public will be invited to try and find a solution to the quite tricky problem of accurate reconstruction of particle trajectories in the collisions at the LHC. The various detectors simply record the hits where particles pass by, however to make use of this data, the hits in surrounding detector layers must be combined into a single flight path, called a track.

Adjusting hyper-parameters: First step into Bayesian optimisation of DNNs

by Giles Strong

A few months ago I wrote about some work I was doing on improving the way a certain kind of particle is detected at CMS, by replacing the existing algorithm with a neural network. I recently resumed this work and have now got to the point where I show significant improvement over the existing method. The design of the neural network, however, was one that I imported from some other work, and what I want to do is to adjust it to better suit my problem.

The L1 muon trigger algorithms

by Ioanna Papavergou

The last CMS week of the year was held two weeks ago, summarizing all the upgrades and changes that happened in 2017, but also the plans of the groups for 2018. Since my service work concerns the L1 muon trigger performance, I was asked by the data performance group conveners to give a talk about the muon trigger algorithms and the improvements that happened last year.

What if you want to get your analysis published?

by Pietro Vischia

I have spent the last few hours editing a paper for an analysis I have been working on with some colleagues in the last year, and I am so bored that I stopped for a few minutes to tell you how preparing a paper in a large experimental collaboration works.

Marie Skłodowska-Curie: The scientist, the legacy, the grants

by Anna Stakia

Maria Skłodowska was born on November 7^th, 1867 in Warsaw, Poland (in the part then dominated by the Russian Empire). Being brought up in a family of teachers, Maria quickly grew interest in acquiring higher education; this was initially and partly achieved through attending Warsaw’s local schools, but also within her own family environment, receiving some scientific training from her father.

Things that Decay into Boson Pairs

by Tommaso Dorigo

Writing a serious review of research in particle physics is a refreshing job – all the things that you already knew on that specific topic once sat on a fuzzy cloud somewhere in your brain, and now find their place in a tidily organized space, with clear interdependence among them. That’s what I am experiencing as I progress with a 60-pageish thing on hadron collider searches for diboson resonances, which will appear sometime next year in a very high impact factor journal.

One of the things that the review must cover is a theoretical overview of the models that the searches for these physics processes address. So I thought I would say a few words on this topic here – but bear in