Trial factors for the look elsewhere effect in high energy physics article in european physical journal c 701 may 2010 with 63 reads how we measure reads. Second workshop, third summary rockefeller university. A commonly cited research to explain the look elsewhere effect apart from the higgs boson is the swedish study that explored the potential health concerns of living near high voltage powerlines in 1992. It is argued that the \xy\ cancellation model xycm is a good proxy for discussions of finetuned cancellations in physical theories. Higgs evidence and the look elsewhere effect at the workshop philosophy of physics in belgrade. Nuclear instruments and methods in physics research section a. Trial factors for the look elsewhere effect in high energy physics.
Aug 29, 2011 to control for this lookelsewhere effect, the data must be normalized for the number of places searched in which a fluctuation could be observed. After a brief characterization of the higgs particle and the look elsewhere. Now, doctors use particle beams for the diagnosis and healing of millions of patients. The present article analyses this conceptual disagreement, which points towards a more general question about the epistemological status of measurement in high energy physics and may be expected to be of increasing importance in the future.
The theoretical high energy physics research group explores the mathematical and theoretical nature of high energy physics, including. The search for the higgs boson was a 40year effort by physicists to prove the existence or nonexistence of the higgs boson, first theorised in the 1960s. Imagine you look for a heavy particle decaying into a pair of hadronic jets. In particle physics, it is common to use a system of natural units with c, the speed of light, set equal to 1, so that all three quantities energy, mass, and momentum can be expressed in ev.
It is called look elsewhere effect, lee for insiders. Perspectives in high energy physics in memory of benjamin whiso lee jan. Linnemann presented an interesting graphical method to prioritize subsets in the space of alternative hypotheses, in such a way that the lee causes less signi. The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing the excess at some fixed mass point, to the probability of observing it anywhere in. The higgs boson was the last unobserved fundamental particle in the standard model of particle physics, and its discovery was described as being the ultimate verification of the standard. Statistical methods in particle physics ws 201718 k. Research illinois physics is ranked among the top 10 physics departments in the u.
The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing the excess at. Normally, experiments in high energy physics dont just search for new. Trial factors or the look elsewhere effect in high energy physics e. Apart from ironband features, the spectrum is described by a powerlaw continuum, with any spectral distortions at the high energy physics.
Here we attempt to quantify this effect in terms of a trial factor, which is the ratio of the probability of observing the. Back at the snowmass on the mississippi meeting, fermilab physicist herman white, who also recorded a video for the why particle physics matters project, drove this point home. Here we attempt to quantify this effect in terms of a trial factor, which is the ratio of the probability of observing the excess at. You have your background model, which predicts the observable shape of the dijet mass distribution, and you know what kind.
Statistics for high energy physics cern document server. This new second edition significantly expands on the original material, with more background content e. Some%peculiari4es% complex%and%sophis4cated%instrumenta4on% large%physical%dimensions% high%investment% large%time%scale%. After a brief characterization of the higgs particle and the look elsewhere effect in sections 2 and 3, the core problem associated with interpreting the data is presented in. Read the latest articles of nuclear instruments and methods in physics research section a. Statistical methods for data analysis in particle physics. The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing. The lookelsewhere effect is a phenomenon in the statistical analysis of scientific experiments. Nuclear radiation, fuel cycles, waste and proliferation 3335.
Buy this book ebook 58,84 price for spain gross buy ebook isbn 9783319628400. The compact muon solenoid cms collaboration at the lhc has now performed many searches for new physics, and seen very few potential bumps. An introduction to high energy physics john campbell, hep argonne national laboratory useful references. Selecting this option will search all publications across the scitation platform selecting this option will search all publications for the publishersociety in context. The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing the excess at some. Bayesian versus frequentist probability theory data analysis in high energy physics experimental particle physics and data analysis hypothesis testing and discoverybased science modified frequentist approach parameter estimation and uncertainties statistics textbook for particle physics look elsewhere effect. High energy physics physics university of colorado boulder. The effect can be quantified in terms of a trial factor, which is the ratio between the probability of. The look elsewhere effect 7 some additional issues on this topic. Employing a 490 ks high energy transmission gratings exposure, we obtain a high quality 19 kev spectrum free from photon pileup and icm contamination. Introduction to high energy physics kindle edition by donald h. This introductory, algebrabased, twosemester college physics book is grounded with realworld examples, illustrations, and explanations to help students grasp key, fundamental physics concepts.
The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing the excess at some fixed mass point, to the probability of observing it anywhere in the range. The complexity of the discovery process in particle physics does not end with concerns about what exact data should be chosen out of the sea of interactions. Trial factors for the look elsewhere effect in high energy. Use features like bookmarks, note taking and highlighting while reading introduction to high energy physics. Trial factors for the look elsewhere effect in high energy physics core. This online, fully editable and customizable title includes learning objectives, concept questions, links to labs and simulations, and ample practice opportunities to solve traditional physics.
Introduction to high energy physics, 4th edition this highly regarded text provides an uptodate and comprehensive introduction to modern particle physics. This includes alternatives to pvalue tests, the look elsewhere effect, measurement sensitivity, implicit statisticalmodels,partondensityuncertainties,referencepriors,pro. Astrophysical limits on very light axionlike particles. Solved the open problem of look elsewhere effect in high energy physics and used since then in all searches, also outside high energy physics. Experiment in physics stanford encyclopedia of philosophy. An emphasis is put on hypothesis test using the asymptotic formulae formalism and its derivation, and on the derivation of the trial factor formulae in one and two dimensions. The effect can be quantified in terms of a trial factor, which is the ratio between the probability of observing the excess.
Statistical issues in searches for new phenomena in high energy. Without getting too much into the physics, the look elsewhere effect is just another name for multiple comparisons. Nuclear instruments and methods in physics research. A side effect of such a broad range quest is that the significance calculations valid for signals of known location are no more applicable when such an information is missing. The observation that generally differential cohomology is the correct formalism for describing gauge fields in physics originates around. Higgs discovery and the look elsewhere effect philsciarchive. Discoveries in particle physics make up much of the fundamental base of knowledge necessary to operate many systems in our complex world, he said. The lookelsewhere effect is a phenomenon in the statistical analysis of scientific experiments where an apparently statistically significant observation may have actually arisen by chance because of the sheer size of the parameter space to be searched.
After accounting for the look elsewhere effect, the posttrial significance of this mediumscale feature is at the level of 4. When searching for a new resonance somewhere in a possible mass range, the significance of observing a local excess of events must take into account the probability of observing such an excess anywhere in the range. Remember the lookelsewhere effect is when we test a single. Download citation the profile likelihood ratio and the look elsewhere effect in high energy physics the experimental issue of the search for new particles of unknown mass poses the challenge. Dan freed, mike hopkins, on ramondramond fields and ktheory. Instead of using joules, they measure the energy in kilowatthours. It is called lookelsewhere effect, lee for insiders. Trial factors for the look elsewhere effect in high energy physics gross, eilam. May 11, 2010 when searching for a new resonance somewhere in a possible mass range, the significance of observing a local excess of events must take into account the probability of observing such an excess anywhere in the range. We report evidence for a narrow structure, x5568, in the decay sequence x5568bs0. Perkins introduction to high energy physics addisonwesley publishing company inc.
Download it once and read it on your kindle device, pc, phones or tablets. This circumstance is commonly termed in high energy physics applications as the look elsewhere effect. This option allows users to search by publication, volume and page selecting this option will search the current publication in context. From the earliest days of high energy physics in the 1930s to the latest 21stcentury initiatives, the bold and innovative ideas and technologies of particle physics have entered the mainstream of society to transform the way we live. Oct 15, 2010 when searching for a new resonance somewhere in a possible mass range, the significance of observing a local excess of events must take into account the probability of observing such an excess anywhere in the range. The electron volt is the amount of energy gained by an electron when traversing a potential difference of 1 v. Motivated by this, the theory of differential cohomology itself was developed in. Its scientific aim is to uncover the ultimate building blocks of matter, space and time.
The look elsewhere effect is a phenomenon in the statistical analysis of scientific experiments where an apparently statistically significant observation may have actually arisen by chance because of the sheer size of the parameter space to be searched. The profile likelihood ratio and the look elsewhere effect in. Phys 210 6 highenergy physics experimental techniques 1. Statistical methods in particle physics heidelberg university. Protons and neutrons, in turn, are made from three quarks, which are also believed to be elementary particles. Look elsewhere effect bayesian methods statistical modeling in practice building binned likelihoods choosing pdfs in unbinned likelihoods implementing systematics blue. If the background is known and there is gaussian noise, the amount of excess of successive observations can be quantified by the squares squaresofrunresiduals sum statistic taking care of the look elsewhere effect. Oct 18, 2017 many experiments in physics involve searching for a localized excess over background expectations in an observed spectrum. Many experiments in physics involve searching for a localized excess over background expectations in an observed spectrum.
Xycm is then analyzed from a statistical perspective, where it is argued that a finetuned point in the parameter space is not abnormal, with any such point being just as probable as any other point. Such units are not very appropriate in high energy physics. The profile likelihood ratio and the look elsewhere effect. A p value tells you the probability of randomly detecting your signal if there is really no signal. Because of the scale at which its experiments are conducted and the diverse branches of physics and mathematics its theories draw from. Trial factors or the look elsewhere effect in high energy. The astrophysical journal letters, volume 886, number 1. High energy physics hep performs exciting, cuttingedge theoretical and experimental research in quantum fields, particles and gravity. String theory, final theory claim and realism at the workshop quantum gravity in perspective in munich. However it is not clear how high energy physicists would. Trial factors or the look elsewhere effect in high energy physics. The role of statistics in the discovery of a higgs boson. Estimating the look elsewhere effect when searching for a signal.
Although these methods are somewhat idiosyncratic to high energy physics, they. Suppose we have a pdf characterized by one or more parameters. Lyons, statistics for nuclear and particle physics, cup, 1986. Similar results for some cases of multidimensional problems 3 4 were applied to statistical tests in the. Vitells trial factors for the look elsewhere effect in high energy physics, eur. Fermilab science particle physics benefits of particle. All you need to know to get started on particle physics. Extensively rewritten and updated, this fourth edition includes all the recent developments in elementary particle physics, as well as its connections with cosmology and astrophysics. The search for high energy neutrinos a tde stacking analysis robert stein for the icecube collaboration. Higgs discovery and the look elsewhere effect semantic scholar.