Observation of a New Particle in the Search for the Standard Model Higgs Boson with the ATLAS Detector

ATLAS Collaboration · Physics Letters B / arXiv · 2012 · physics · record atlas2012-higgs
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Where this record's text came from. faceted 2026-08 by reading the locally held text (pdftext); every evidence string verified as an exact substring of that text before merging. method: none of the suggested method values fits a collider search, so 'collider-experiment' is used; the paper's own simulation work (Geant4, MC generators) is an input to the analysis, not its design. Replication status 'replicated' reflects what the article itself reports: the 2011 ATLAS and CMS datasets had already shown 2.9 and 3.1 sigma excesses in the same 124-126 GeV region, and the 2012 data alone reach 4.9 sigma at mH = 126.5 GeV, so the excess appears in independent datasets - but the paper never describes itself as a replication. Only one claim_relation is recorded: the sentences stating the combination with the earlier ATLAS 7 TeV results [17] are interleaved with formulae and channel symbols by the PDF extraction and could not be quoted intact, and the prior-excess sentence describes earlier work without explicitly relating this paper to it. Long stretches of the file are detector description, systematic-uncertainty tables and the collaboration author list. 2026-08-14, 2026-08-16 and 2026-08-25 schema-0.3 passes: every quote verified as an exact substring of the staged text and anchored at merge time; concept terms verified present; every edge endpoint an existing node. Update, 15 September 2026: EXCEPTION, measured with the merge gate's own predicate (Paper.locate): 1 quote(s) on this record are not found as one exact string in the current staged text - content_tags.statistics[2].evidence. The sentence above does not hold for them as written. Where a row records why - the quote is grounded in another copy of the paper, joins two passages with an ellipsis, or differs from the staged text by extraction noise - that note stays on the row.

The quality of the text these quotes were cut from. symbol-font-not-extractable: 16 '(cid:NNN)' glyph-index markers remain in a staged text of 96,004 characters, where the PDF's embedded font had no ToUnicode map. THE QUOTES ON THIS RECORD ARE THE PAPER'S AND THE STAGED COPY IS THE DAMAGED ONE - which is the opposite of the usual case and is why it went unnoticed: one of its 60 live quotes is not an exact substring of this text, and it could NOT be located in it even by aligning the quote's WORD SEQUENCE under this damage, so the defect recorded here is present on the record but does not by itself account for the miss. Not repaired in place: editing the staged text moves every offset after the edit and re-hashes every anchor on the record. Measured at 113aae60fefc3eb1, re-measured unchanged at 54b63482778ddf56.

Some words in these quotes contain the wrong character. The PDF this text was extracted from substituted 3 characters inside a word — a currency sign or a stray accent where a letter pair belongs, as in signi¢cantly for significantly, or a single ligature glyph, as in conﬁdence. They are valid characters in the wrong place, so they survive every encoding check. The quotes keep them for the same reason as above, and a search of this page will not find the affected words.

1 quote on this page was cut from a different copy of this article. This project holds two extractions of this paper: the plain text every other quote here is anchored in, and the publisher’s own HTML edition, which we are not licensed to republish. It is verbatim in the second and cannot be found in the first — not because the tagging is wrong, but because the extraction damaged the passage: a page number dropped into the middle of a number, a formula moved out of its sentence, a ligature where two letters belong. The record names the copy for each one. The quote is the paper’s; the extraction is not.

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Other fields define these differently the same word, defined another way in another discipline
significance 3 fields · standard-deviation 3 fields · statistical-power 2 fields · ATLAS 2 fields

Tags on this paper

Every tag the record carries, each linking to every other paper in the corpus that carries it. A tag appears here whether or not its words occur in the article — the spans below are only the ones a sentence in this paper licenses. Of the 8 concept tags on this paper, 4 are grounded in a quoted sentence.

Higgs boson Standard Model particle physics Large Hadron Collider local significance global significance trials factor Standard Model Higgs boson the whole search is reduced to ONE parameter of interest - a signal strength that scales the predicted signal - and it is defined so that zero is the background-only hypothesis and one is the Standard Model Higgs signal, so the hypothesis under test is a value of that one factor hypothesised values of that strength are tested with a profile likelihood ratio, which extracts the signal strength from a full likelihood fit whose function INCLUDES all the parameters describing the systematic uncertainties and their correlations exclusion is decided by a stated numerical rule rather than by judgement: a signal strength is excluded at 95% confidence when its CLs value falls below 5%, and a Standard Model Higgs of a given mass counts as excluded when the value one is excluded at that mass the size of an excess is first expressed as the probability that background alone could produce a fluctuation at least that large, and only then converted into the equivalent number of standard deviations - the local significance that local number is then corrected for having searched a whole mass range rather than one point: the ratio of global to local probability is the trials factor, and the paper states what it depends on - the range of hypotheses considered, the mass resolutions of the channels combined, and the size of the excess itself the tests are run in steps across the hypothesised mass rather than at one chosen point, and the asymptotic approximation the results rest on is not assumed to hold - it is validated by a separately described method the combination across channels is built on the same single signal strength together with an explicit identification of which nuisance parameters correspond to the CORRELATED sources of systematic uncertainty the jet energy scale and resolution are handled by a deliberately simplified scheme - independent nuisance parameters attached to final states with materially different selections and process sensitivity - and the simplification is defended by measurement: the results were found insensitive to the assumptions made about how those sources correlate ATLAS LHC electroweak symmetry proton-proton collisions significance standard deviations luminosity scalar particle SM Higgs boson pile-up Higgs boson mass mH centre-of-mass energy √s integrated luminosity chi-square p-value p-values standard-deviation statistical-power statistical power experiment

Method, as described: collider-experiment

Legend

relation to other work	`claim_relations`	how this paper stands to another: agrees, contradicts, extends, qualifies
claim type	`claim_type`	the shape of the claim: existence, mechanism, method, critique, prediction, null
concept edge	`concept_edges`	an asserted relation between two concepts, with the sentence asserting it
concept	`concepts`	an idea the paper works with, quoted where the paper uses it
content tag	`content_tags`	a finding, definition, quantity, statistic or variable named in the paper
control	`controls`	an experiment run to eliminate a rival explanation
limitation	`limitations`	what the paper says its evidence cannot support
mechanism	`mechanisms`	how the reported effect is said to come about
method	`method`	how the paper produced its evidence
phenomenon	`phenomenon`	the effect or regularity under study
sense	`senses`	a distinct use of a term, quoted where the paper fixes it
transfer	`transfers`	a method or concept carried in from another field

The paper

The full text is not reproduced here. This article is not cleared for redistribution, so the page carries the tag layer only. Its evidence sentences are withheld; the grounding status remains with each tag, and the article itself is at https://arxiv.org/abs/1207.7214. The reading view exists for the papers whose licence permits it.

Every tag on this page

claim_relations 2 · claim_type 1 · concept_edges 2 · concepts 4 · content_tags 19 · controls 4 · limitations 6 · mechanisms 8 · method 1 · phenomenon 1 · senses 3 · transfers 1

Relations on this page carry a quotation for the claim. Where a relation was separately evidenced — and so tested against the vocabulary for its type — the row says so; none of 2 relations here carry that mark. The rest are the tagger’s reading of the sentence quoted beside them.

facet	tag	field	conf.	whose words
claim_type	existence Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_type`		the paper's words
phenomenon	Standard Model Higgs boson search Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`phenomenon`		the paper's words
method	experiment Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: experiment	`method`		the paper's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the whole search is reduced to ONE parameter of interest - a signal strength that scales the predicted signal - and it is defined so that zero is the background-only hypothesis and one is the Standard Model Higgs signal, so the hypothesis under test is a value of that one factor	`mechanisms[0]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: hypothesised values of that strength are tested with a profile likelihood ratio, which extracts the signal strength from a full likelihood fit whose function INCLUDES all the parameters describing the systematic uncertainties and their correlations	`mechanisms[1]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: exclusion is decided by a stated numerical rule rather than by judgement: a signal strength is excluded at 95% confidence when its CLs value falls below 5%, and a Standard Model Higgs of a given mass counts as excluded when the value one is excluded at that mass	`mechanisms[2]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the size of an excess is first expressed as the probability that background alone could produce a fluctuation at least that large, and only then converted into the equivalent number of standard deviations - the local significance	`mechanisms[3]`	0.95	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: that local number is then corrected for having searched a whole mass range rather than one point: the ratio of global to local probability is the trials factor, and the paper states what it depends on - the range of hypotheses considered, the mass resolutions of the channels combined, and the size of the excess itself	`mechanisms[4]`	0.95	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the tests are run in steps across the hypothesised mass rather than at one chosen point, and the asymptotic approximation the results rest on is not assumed to hold - it is validated by a separately described method	`mechanisms[5]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the combination across channels is built on the same single signal strength together with an explicit identification of which nuisance parameters correspond to the CORRELATED sources of systematic uncertainty	`mechanisms[6]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the jet energy scale and resolution are handled by a deliberately simplified scheme - independent nuisance parameters attached to final states with materially different selections and process sensitivity - and the simplification is defended by measurement: the results were found insensitive to the assumptions made about how those sources correlate	`mechanisms[7]`	0.95	the tagger's words
limitations	The data establish a new neutral boson but are insufficient to determine whether it is in fact the Standard Model Higgs boson. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the identification of the particle, as distinct from its discovery: THESE RESULTS ARE COMPATIBLE WITH THE HYPOTHESIS THAT THE NEW PARTICLE IS THE STANDARD MODEL HIGGS BOSON, [but] MORE DATA ARE NEEDED TO ASSESS ITS NATURE IN DETAIL	`limitations[0]`		the tagger's words
limitations	Increased pile-up degraded missing-transverse-momentum resolution so badly that the same-flavour WW final states had to be dropped from the 8 TeV analysis. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the 8 TeV WW analysis specifically: SINCE THE e-mu CHANNEL PROVIDES MOST OF THE SENSITIVITY OF THE SEARCH, ONLY THIS FINAL STATE IS USED - pile-up degraded the resolution the same-flavour states needed	`limitations[1]`		the tagger's words
limitations	The same excess carries three significances: 5.9 sigma locally, about 5.1 sigma globally over 110-600 GeV, and 5.3 sigma over a narrower range whose bounds are lost to figure text in this staged copy. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the 5.9 sigma figure as the discovery significance: the paper gives about 5.1 sigma globally over 110-600 GeV, and a different value again over a narrower range	`limitations[2]`	1.0	the tagger's words
limitations	The correction from local to global significance is stated to depend on the mass range searched, the channels' mass resolutions, and the size of the excess. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: comparing significances across searches: the trials factor depends on the range of hypotheses considered, so the same excess yields different global significances	`limitations[3]`	1.0	the tagger's words
limitations	Compatibility with the Standard Model expectation is quantified at the 1.5 sigma level rather than asserted. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the result as agreement with the Standard Model: the paper quantifies the compatibility at 1.5 sigma	`limitations[4]`	1.0	the tagger's words
limitations	Only the spin-1 hypothesis is addressed, and only by the diphoton observation. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the new particle's spin: only spin-1 is disfavoured here, by the diphoton observation alone	`limitations[5]`	1.0	the tagger's words
transfers	statistical significance testing (p-values, sigma levels) used to establish the discovery of a new particle against background fluctuations Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`transfers[0]`		the tagger's words
controls	control and validation regions built with the signal-region selections but with criteria reversed or modified, so the samples are depleted of signal Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. eliminates: a background estimate taken from the same events as the signal - the reversed criteria give regions where the signal cannot be, and the background can therefore be measured rather than assumed · outcome (stated by the tagger, no quotation): held	`controls[0]`	0.9	the tagger's words
controls	validation regions kept separate from the control regions used to normalise the backgrounds, with the paper stating which does which Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. eliminates: checking the background model on the very regions that were used to fit it - the distinction is what keeps the check independent of the fit · outcome (stated by the tagger, no quotation): held	`controls[1]`	0.9	the tagger's words
controls	data-driven estimation of the numbers of two-photon, photon-jet and jet-jet events in the selected sample Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. eliminates: reliance on simulation for the backgrounds hardest to simulate - jets faking photons is precisely where Monte Carlo is least trusted, so that component is measured from data · outcome (stated by the tagger, no quotation): held	`controls[2]`	0.9	the tagger's words
controls	a trials factor applied to convert the local probability to a global one, correcting for the range of Higgs mass hypotheses searched Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. eliminates: having looked in many places and reported the luckiest - the look-elsewhere correction is what makes the quoted significance a statement about the search rather than about one bin · outcome (stated by the tagger, no quotation): held	`controls[3]`	0.9	the tagger's words
concepts	local significance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: local significance	`concepts[4]`		the paper's words
concepts	global significance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: global significance	`concepts[5]`		the paper's words
concepts	trials factor Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: trials factor	`concepts[6]`		the paper's words
concepts	Standard Model Higgs boson Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: Standard Model Higgs boson	`concepts[7]`		the paper's words
senses	local significance - the number of standard deviations corresponding to the background producing a fluctuation at least as large as the excess observed, at one mass Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`senses[0]`	1.0	the tagger's words
senses	global significance - the same excess corrected for having searched a whole mass range, which lowers 5.9 sigma to approximately 5.1 sigma over 110-600 GeV Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`senses[1]`	1.0	the tagger's words
senses	trials factor - the ratio of global to local probability, larger the wider the range of hypotheses searched Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`senses[2]`	1.0	the tagger's words
claim_relations	builds-on → the Standard Model Higgs prediction Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[0]`		the tagger's words
claim_relations	extends → the previous ATLAS H->ZZ(*)->4l analysis, Ref. [83] Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[1]`		the tagger's words
concept_edges	global significance —distinct-from→ local significance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span reports the global significance of a local excess; distinct-from is loose. also in: global significance · local significance	`concept_edges[0]`		the tagger's words
concept_edges	trials factor —part-of→ global significance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the trials factor is the RATIO of global to local probabilities, used to correct; part-of is loose. also in: trials factor · global significance	`concept_edges[1]`		the tagger's words
content_tags	5.9 — discovery significance of the new boson Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.quantities[0]`		the tagger's words
content_tags	126.0 — measured mass of the new neutral boson Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.quantities[1]`		the tagger's words
content_tags	7 — 2011 collision centre-of-mass energy Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.quantities[2]`		the tagger's words
content_tags	124-126 — mass region of the 2011 excess Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.quantities[3]`		the tagger's words
content_tags	2.9 and 3.1 — ATLAS/CMS 2011 excess significances Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.quantities[4]`		the tagger's words
content_tags	~10 to ~20 — pile-up in 7 TeV vs 8 TeV data Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.quantities[5]`		the tagger's words
content_tags	the observation reaches 5.9 sigma significance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.findings[1]`		the tagger's words
content_tags	the Higgs was the only SM particle not yet observed Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.findings[3]`		the tagger's words
content_tags	Higgs boson mass mH Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: Higgs boson mass mH	`content_tags.variables[0]`		the tagger's words
content_tags	centre-of-mass energy √s Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: centre-of-mass energy √s	`content_tags.variables[1]`		the tagger's words
content_tags	integrated luminosity Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: integrated luminosity	`content_tags.variables[2]`		the tagger's words
content_tags	pile-up Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: pile-up	`content_tags.variables[3]`		the tagger's words
content_tags	SM Higgs boson Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: SM Higgs boson	`content_tags.definitions[0]`		the tagger's words
content_tags	electroweak symmetry Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: electroweak symmetry	`content_tags.definitions[1]`		the tagger's words
content_tags	Standard Model Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: Standard Model	`content_tags.definitions[2]`		the tagger's words
content_tags	pile-up Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: pile-up	`content_tags.definitions[3]`		the tagger's words
content_tags	chi-square Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. about this quote: QUOTE RECOVERED FROM THE PAPER'S OWN CHARACTERS. The recorded quote was LETTERS-ONLY IDENTICAL to this stretch of the staged text but not an exact substring of it - spaces, hyphens, ligature glyphs or mathematical operators differed, so it could never anchor. This is the file's own text between the same two letters: not produced by a rule about the damage, copied out of the file. Round-trip checked (the recovered span is letters-only equal to the original) and length-checked. The text as originally recorded is kept in evidence as extracted. also in: chi-square	`content_tags.statistics[0]`		the tagger's words
content_tags	p-value Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: p-value	`content_tags.statistics[1]`		the tagger's words
content_tags	statistical-power Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: statistical-power	`content_tags.statistics[3]`		the tagger's words

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