Is the new 3.0 TeV bump at ATLAS a fluke?

In summary: So the background uncertainty directly translates to the signal uncertainty.In summary, the ATLAS experiment has observed a potential new particle at a mass of 3.0 TeV/c^2 with a local significance of more than three sigma and a global significance of a bit more than two sigma. This bump has been attributed to a heavy vector boson hypothesis and has been described in a preprint published on arXiv. However, it is more likely to be a fluke as it has a low global significance and is not well-motivated. The search used 36.1 fb−1 of proton-proton collision data and the results are in agreement with the Standard Model expectations. Upper limits have been set for the production of this particle
  • #1
ohwilleke
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The ATLAS experiment has seen a bump that could be a new particle at a mass of 3.0 TeV/c^2 with a local significance of more than three sigma, and a global significance of a bit more than two sigma in Run-2 data looking at decays of qqbb states to a W or Z boson and a Higgs boson.

It is possible to fit this into a "heavy vector boson" hypothesis (such as a W' or Z' model), but I think it is more likely to be a fluke, as it isn't very well motivated and has a low global significance. The preprint is as follows:

arXiv:1707.06958 [pdf, other]
Search for heavy resonances decaying to a W or Z boson and a Higgs boson in the qq¯(′)bb¯ final state in pp collisions at s√=13 TeV with the ATLAS detector
ATLAS Collaboration
Comments: Comments: 18 pages plus author list + cover pages (36 pages total), 5 figures, 4 tables, submitted to PLB, All figures including auxiliary figures are available at this https URL
Subjects: High Energy Physics - Experiment (hep-ex)

A search for heavy resonances decaying to a W or Z boson and a Higgs boson in the qq¯(′)bb¯ final state is described. The search uses 36.1 fb−1 of proton-proton collision data at s√= 13 TeV collected by the ATLAS detector at the CERN Large Hadron Collider in 2015 and 2016. The data are in agreement with the Standard Model expectations, with the largest excess found at a resonance mass of 3.0 TeV with a local (global) significance of 3.3 (2.1) σ. The results are presented in terms of constraints on a simplified model with a heavy vector triplet. Upper limits are set on the production cross-section times branching ratio for resonances decaying to a W (Z) boson and a Higgs boson, itself decaying to bb¯, in the mass range between 1.1 and 3.8 TeV; the limits range between 83 and 1.6 fb (77 and 1.1 fb) at 95% confidence level.
 
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  • #2
ohwilleke said:
The data are in agreement with the Standard Model expectations
These are the key words. This is not even a 3 sigma deviation from the SM.
 
  • #3
Orodruin said:
These are the key words. This is not even a 3 sigma deviation from the SM.

I don't disagree, but I pretty much guarantee that it will produce a bunch of phenomenology papers at arXiv as it is one of the bigger bumps or anomalies out there that hasn't been around for years.
 
  • #4
Oh, I don't doubt that it will. There is a high chance those will be thrown in the trash bin in one year's time.

I do not think it is bad per se to explore the possibility of a signal. It becomes bad when you jump at every 2 sigma deviation while yelling "This is it!" since, most likely, it isn't.
 
  • #5
Orodruin said:
It becomes bad when you jump at every 2 sigma deviation while yelling "This is it!" since, most likely, it isn't.
Bad for who? If you are wrong, everybody will forget it soon anyway. If you are right (the chances are small, but still), you will become a hero. :biggrin:
 
  • #6
Demystifier said:
If you are wrong, everybody will forget it soon anyway.
I disagree. I know of several people who are well known for being people who cry wolf ...
 
  • #7
Orodruin said:
I disagree. I know of several people who are well known for being people who cry wolf ...
OK, can you give their names?
 
  • #8
Demystifier said:
OK, can you give their names?

Resorting to what amounts to slander on an open forum on the internet where they have no opportunity of responding and if they do where I am easily identifiable? I don't think so.
 
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  • #9
Orodruin said:
There is a high chance those will be thrown in the trash bin in one year's time.
Or faster if CMS won't have a bump at the same place.

The small excess ATLAS has is higher than the expectations for the model they test. If that would be a signal, it would be an unexpectedly strong one.
 
  • #10
mfb said:
Or faster if CMS won't have a bump at the same place.
Let me reformulate to my intended meaning: "will have been thrown away one year from now" :rolleyes:
 
  • #11
I didnt have the time to read through the whole analysis in the paper, yet I find it interesting...
I wonder why they don't mention signal systematics (like PDF systs)...
 
  • #12
The background estimate is from data, no PDFs involved. The potential signal strength is just given in terms of cross section, again no PDFs involved. There are some uncertainties related to MC, they are discussed on page 10.
 
  • #13
No, I was asking for signal systematics, not SM bkg...
 
  • #14
The background description is part of the systematic uncertainty of the signal yield. It is often the largest contribution, because "(observed-background)/efficiency" is the signal (simplified description), and the number of observed events is known and the efficiency is often well-known as well.
 

Related to Is the new 3.0 TeV bump at ATLAS a fluke?

1. What is the 3.0 TeV bump at ATLAS?

The 3.0 TeV bump at ATLAS refers to a potential new particle signal observed at the ATLAS experiment at the Large Hadron Collider (LHC). It appears as a localized excess of events at a mass of approximately 3.0 TeV, which could indicate the existence of a new particle or phenomenon not yet accounted for by the Standard Model of particle physics.

2. How was the 3.0 TeV bump discovered?

The 3.0 TeV bump was discovered by analyzing data collected by the ATLAS detector at the LHC. Scientists look for deviations from the expected background events in specific channels, and the 3.0 TeV bump was observed in the diphoton channel, where two photons are produced in collisions at the LHC.

3. Is the 3.0 TeV bump a confirmed discovery?

No, the 3.0 TeV bump is not yet a confirmed discovery. It is currently considered a potential signal that requires further investigation and confirmation. Scientists are working to collect more data and analyze it in different ways to determine if the bump is a real signal or just a statistical fluctuation.

4. What could the 3.0 TeV bump potentially represent?

The 3.0 TeV bump could potentially represent the discovery of a new particle or phenomenon beyond the Standard Model. It could also be a statistical fluctuation or a systematic error in the data. Further studies and analysis are needed to determine the true nature of the bump.

5. What are the implications of the 3.0 TeV bump if it is confirmed?

If the 3.0 TeV bump is confirmed as a real signal, it could have significant implications for our understanding of particle physics and the fundamental building blocks of the universe. It could also open up new avenues for research and potentially lead to the discovery of new particles and phenomena. However, further studies and confirmation are needed before any definitive implications can be determined.

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