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AMVA4NewPhysics

A Marie Sklodowska-Curie ITN funded by the Horizon2020 program of the European Commission

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New physics

Recasting new physics searches at the LHC

The AMVA4NewPhysics work package I am involved in is related to developing tools for recasting new physics searches, with a particular focus on multivariate analyses. I would like to explain a little more about it in this article.
Let me begin by describing the motivation to look for new physics at the Large Hadron Collider (LHC). Despite the fact that the Standard Model (SM) of particle physics is very successful at describing most properties of elementary particles, there are many reasons to believe that nature is much more complicated and there is new physics, or physics beyond the Standard Model (BSM). Firstly, there is the hierarchy problem that asks why the electroweak scale or the Higgs mass, 125 GeV can be so light compared to the cutoff scale of the SM, the Planck scale if there is no BSM physics, which is 17 orders of magnitude larger than the electroweak scale. The Higgs mass is unprotected by any symmetry in the SM, and the quantum corrections to its mass are proportional to the cutoff scale. One requires an extreme fine tuning to keep the Higgs boson light while renormalizing the quantum effects, which seems to be totally unnatural. Secondly, as explained previously, there exists dark matter, which is thought by many to be a new type of elementary particle. For these and many other motivations, people are excited at the prospects of discovering BSM physics at the LHC.

Continue reading “Recasting new physics searches at the LHC”

Dark Matter Hunting at the LHC

by Seng Pei Liew

photo1Hello there! My name is Seng Pei Liew, and I am the “Marie Sklodowska-Curie Actions” Innovative Training Network (AMVA4NewPhysics) early-stage researcher based at the Technische Universitat Munich (TUM). I am tasked in the network to look for new physics at the Large Hadron Collider (LHC) using advanced statistical tools. In my very first article here, I would like to talk Continue reading “Dark Matter Hunting at the LHC”

W Mass: Closing In

by Tommaso Dorigo

After a lot of agonizing work on tiny systematic uncertainties, the ATLAS collaboration released in time for the Moriond conference their latest measurement of the W boson mass (in fact the only one so far). The result is in close match with previous determinations, and has a slightly larger error bar than those. So why bother discussing it here ?

There is a reason. The W boson is one of the most important subatomic particles Continue reading “W Mass: Closing In”

New Decay Of Lambda_b Seen By LHCb!

by Tommaso Dorigo

The so-called Lambda_b baryon is a well-studied particle nowadays, with several experiments having measured its main production properties and decay modes in the course of the past two decades. It is a particle made of quarks: three of them, like the proton and the neutron. Being electrically neutral, it is easily likened to the neutron, which has a quark composition “udd”. In the space of quark configurations, the Lambda_b is in fact obtained by exchanging a down-type Continue reading “New Decay Of Lambda_b Seen By LHCb!”

Brazil Bands: What Are They ?

by Tommaso Dorigo

As I am traveling around Europe this week, giving seminars in several places (Hamburg yesterday, Berlin today, and Clermont-Ferrand on Friday) my connectivity is erratic and my capability to follow the development of data analysis and new publications is strongly lowered. My connections to the world of LHC research continues through email exchanges, though.

One thread I found in my mailbox this morning developed from a question on the use and meaning of the so-called “Brazil Bands”, a feature of Continue reading “Brazil Bands: What Are They ?”

Story of a Failed Resonance

by Tommaso Dorigo

The DZERO collaboration published earlier this year a search for resonances decaying to  pairs in its Run-2 dataset of 2-TeV proton-antiproton collisions, produced by the now defunct Tevatron collider in the first 10 years of this century. Starting from a sample of about 5600 B_s events, they surprisingly claimed Continue reading “Story of a Failed Resonance”

Approaching General Searches, part I

by Fabricio Jiménez

This time I’m going to write about the ways of approaching general searches for new phenomena. I invite you to read my previous post to get some context, if you haven’t already. The essence of such searches is to explore as many signatures as possible, without assuming any model of new physics. But how does one do that?

During my last visit to CERN, I had the chance to meet in person for the first time Continue reading “Approaching General Searches, part I”

Six months in

by Giles Strong

Ciao. As the title suggests, it’s been about half a year now since I started my PhD research, and last week I presented a summary of my work so far to the CMS group here in Padova. I thought it would be an interesting exercise to translate my presentation into a more blog-friendly form, but for the more scientifically minded, I’ll link the original at the end. Here goes! Continue reading “Six months in”

Anomaly!

by Tommaso Dorigo

The first few copies of my new book, “Anomaly! – Collider Physics and the Quest for New Phenomena at Fermilab” arrived this morning from Singapore. With pleasure, I was finally able to hold in my hand the result of a long work… It started in 2008, when the unfolding story of an intriguing multi-muon signal in CDF data had me first caress the idea of writing about two decades of investigations carried out by Continue reading “Anomaly!”

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