L'ordine del mondo le simmetrie in fisica da Aristotele a Higgs
Barone, Vincenzo
2013-01-01
Il mondo ci appare come una lunga serie di contingenze locali: ogni fatto accade per ragioni sue e quindi ogni previsione relativa al fatto successivo sembra azzardata. C'è però un altro modo di guardare il mondo, ed è quello fondato sulle regolarità intrinseche, sulle trame ordinate della sua tessitura sottile. In fisica il discorso sulla struttura del mondo giunge a noi addirittura da Anassimandro, ma è con Einstein che si fa strada prepotentemente l'idea di necessità, o di inevitabilità, nel mondo fisico. È con la relatività ristretta, nel 1905, che per la prima volta entra a far parte della fisica il concetto di simmetria come elemento fondamentale della spiegazione del mondo. Da Einstein in poi, il mondo apparirà dotato di una sua struttura intrinseca, che permette lo sviluppo di certe regolarità, mentre ne nega altre, proprio come avviene nel "Castello dei destini incrociati" di Italo Calvino, dove il gioco di incroci tra le storie raccontate dai tarocchi permette alcuni sviluppi narrativi e ...
Spolskij, Eduard Vladimirovic
1986-01-01
Volume I : questo è il primo dei due volumi del corso di fisica atomica scritto da E. V. Spolskij. Quest'opera fondamentale è, per il suo carattere, un'enciclopedia di fisica atomica. Il primo volume, in linea di principio, tratta il basi sperimentali della fisica del micromondo.
Fisica del nucleo stelle di neutroni
Bernardini, Carlo
1982-01-01
Studio sistematico delle masse nucleari ; energia di legame ; raggi nucleari dai nuclei speculari ; il nucleo in approssimazione di Thomas-Fermi ; introduzione allo scattering : caratterizzazione cinematica degli urti ; la sezione d'urto ; il fattore di forma dei nuclei ; gli atomi u-mesici ; proprieta elettromagnetiche statiche dei nuclei (momenti di multipolo) ; momento di quadrupolo elettrico dei nuclei ; momento d dipolo magnetico dei nuclei ; metodo delle risonanze magnetiche nucleari (NMR) ; misura del fattore giromagnetico e del momento di quadrupolo ; modelli nucleari a particelle indipendenti, il modello a shell ; l'interazione spin-orbita ; il modello a shell e le linee di Schmidt per il momento magnetico dei nuclei con "A" dispari ; nuclei non sferici (deformati) ; stelle di neutroni.
La fisica del Novecento per un bilancio critico
Selleri, Franco
1999-01-01
Ma chi ha detto che la fine della fisica è vicina? Che tutto quello che c'era da scoprire è già stato scoperto? E che le generazioni future potranno solo precisare e raffinare, e mai negare o arricchire le attuali teorie? Questo libro si contrappone a pensatori come Heisenberg, Feyman e Hawking che hanno predetto la morte della fisica. L'autore sostiene che grandi progressi sono possibili, ma che il prezzo da pagare per realizzarli è una modifica radicale delle basi della fisica moderna, in particolare abbandonando l'indeterminismo, la non località (paradosso di Einstein, Podolsky e Rosen) e lo stesso principio di relatività.
Degl’Innocenti, Egidio Landi
2008-01-01
Il volume è un'introduzione alla Fisica Solare che si propone lo scopo di illustrare alla persona che intende avvicinarsi a questa disciplina (studenti, dottori di ricerca, ricercatori) i meccanismi fisici che stanno alla base della complessa fenomenologia osservata sulla stella a noi più vicina. Il volume non ha la pretesa di essere esauriente (basta pensare che la fisica solare spazia su un gran numero di discipline, quali la Fisica Nucleare, la Termodinamica, L'Elettrodinamica, la Fisica Atomica e Molecolare, la Spettoscopia in tutte le bande dello spettro elettromagnetico, la Magnetoidrodinamica, la Fisica del Plasma, lo sviluppo di nuova strumentazione, l'Ottica, ecc.). Piuttosto, sono stati scelti un numero di argomenti di rilevanza fondamentale nello studio presente del Sole (soprattutto nei riguardi delle osservazioni da terra con grandi telescopi) e su tali argomenti si è cercato di dare una panoramica generale, inclusiva dell'evoluzione storica, senza scendere in soverchi dettagli. Siccome la Fis...
Born, Max
1976-01-01
Nato sotto forma di una corso di fisica atomica e successivamente ampliato per tener conto dei più recenti progressi nel campo della fisica, il libro di Max Born costituisce una tappa obbligata nella formazione culturale di ogni studente o ricercatore. L'autore, del quale è sufficiente ricordare che è stato una delle massime personalità scientifiche del nostro secolo, ha mirato soprattutto, sviluppando i capitoli fondamentali della fisica nucleare e della fisica quantistica, a delineare con la massima chiarezza i princìpi fisici. Il lettore non è mai distratto da complesse dimostrazioni matematiche; queste sono date in apposite appendici in fondo al volume, e in tal modo sono accresciute la leggibilità del libro e la sua utilità come valida opera di studio e di consultazione.
Maiani, Luciano
2013-01-01
Nel luglio 2012 veniva confermata sperimentalmente, presso i laboratori del CERN di Ginevra, l'esistenza del "bosone di Higgs", la più piccola di tutte le particelle subatomiche fino ad ora scoperte, teorizzata da Peter Higgs fin dal lontano 1964 e divulgata al mondo come "la particella di Dio". Una scoperta che costituisce un fondamentale passo avanti nella fisica delle particelle e nella conferma del modello standard dell'universo, in direzione di quella Teoria del Tutto, la teoria unificata delle forze, che la fisica insegue da decenni. Per giungere alla prima conferma sperimentale sono stati necessari quasi 50 anni di ricerche teoriche e la costruzione della macchina più grande del mondo, l'LHC, Large Hadron Collider, un anello lungo 27 chilometri situato a 100 metri di profondità nel territorio di Ginevra. Una sfida sul cui successo, all'inizio, pochi avrebbero scommesso e che si accompagna alla storia stessa del CERN, il Consiglio Europeo per la Ricerca Nucleare di cui Luciano Maiani è stato diretto...
Introduzione alla fisica matematica
Persico, Enrico
1960-01-01
Cinematica dei mezzi continui, campi scalari e vettoriali ; funzioni armoniche, rappresentazioni confomi ; teoria dell'elasticità ; elettromagnetismo ; conduzione del calore (e diffusione) ; le equazioni a derivate parziali della fisica matematica ; cenni sulla teoria della relatività (ristretta).
Energy Technology Data Exchange (ETDEWEB)
Galles, Carlos D., E-mail: galles@fceia.unr.edu.ar [UNR Universidad Nacional de Rosario, Santa Fe (Argentina); UTN Universidad Tecnologica Nacional (Argentina)
2009-07-01
An overview is given of the principal lines of research into Physics during the end of the nineteenth century. At that time, a long series of successful theories which appeared to be final and conclusive had strengthened a conservative epistemological dogma which held that in the future research would consist merely of ever-more precise measurements, in the absence of any revolutionary innovations. However, it turned out that Nature was to reveal some of her mysterious and unexpected secrets to certain bright minds working in laboratories. (author) [Spanish] Se presentan las principales lineas de investigacion en Fisica en las ultimas decadas del siglo XIX. Una larga serie de exitosas teorias aparentemente finales y conclusivas habian fortalecido por entonces un dogma epistemologico conservador que presagiaba solo se continuaria acumulando mediciones mas y mas precisas sin innovaciones revolucionarias. La naturaleza reservaba sin embargo revelar en los laboratorios, a las mentes agiles, algunos de sus misteriosos e insospechados secretos. (autor)
Cini, Michele
2006-01-01
Le idee e le tecniche della Fisica Teorica del XX secolo (meccanica analitica, meccanica statistica, relatività e meccanica quantistica non relativistica) non sono più appannaggio esclusivo dei fisici. Ormai, specialmente con la recente introduzione di nuovi corsi di laurea, le conoscenze di base rientrano nel bagaglio culturale comune ai laureati in materie scientifiche e tecnologiche affini alla Fisica e alle sue applicazioni. Un laureato in queste materie non può non conoscere l’equazione E=mc2 e la media di Gibbs; inoltre deve avere i concetti e i metodi fondamentali della meccanica quantistica che ha cambiato la concezione del mondo ed è alla base della rivoluzione tecnologica in corso. Eppure quelle idee rimangono distanti dal comune modo di pensare e richiedono molto studio e un insegnamento ben mirato. La trattazione in questo libro, è meno formale rispetto ai tradizionali corsi di Istituzioni di Fisica Teorica. Lo scopo è comunque quello di raggiungere una reale comprensione dei concetti fisi...
Fazio, Michelangelo
2008-01-01
L’introduzione delle lauree triennali ha in molti casi costretto i docenti a ridurre drasticamente il numero di ore di insegnamento e quindi l’estensione dei programmi dei corsi di Fisica. In questo volumetto l'autore si è proposto di esporre sinteticamente ma con il massimo rigore possibile il corso di Fisica Generale I evitando le dimostrazioni delle leggi fisiche, ma dando la priorità alle applicazioni di tali leggi e allo svolgimento di esercizi che in genere viene trascurato in molti corsi. Ha cercato pertanto di presentare i fenomeni fisici sottolineando, dove possibile, la loro presenza nella vita quotidiana e le loro più semplici e immediate applicazioni, consentendo in tal modo agli studenti di vedere la Fisica non più come una interminabile serie di formule ma come un nuovo modo di interpretare e di capire i fenomeni naturali inanimati (del resto non dobbiamo dimenticare che il termine greco da cui deriva il suo nome è fisis, fisis, ovvero natura). Il contenuto è completo, comprendendo anc...
Evaluacion de Mediciones Fisicas y de Ultrasonido para Estimaciones del Peso de la Pechuga
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Melo JE
2001-01-01
Full Text Available El objetivo del presente trabajo fue evaluar la utilización de distintas mediciones como predictores del peso de la pechuga. En la experiencia 1 se utilizaron 32 pollos Anak y 32 pollos Ross, muestreados al azar de dos lotes de 400 animales de cada genotipo. A los 53 dias de edad se realizó la faena y una disección de cortes comerciales. Se tomaron los siguientes pesos: peso vivo (PV, de la canal (PC y de la pechuga (Pch. Se calculó para el análisis la proporción de cada uno sobre el peso vivo (%PC y %Pch. También se midieron el largo y el ancho de la pechuga con calibre. Se observaron diferencias entre genotipos para PV, PC, %PC, Pch y %Pch (p <0,05. Los animales de la línea Ross resultaron más pesados que los Anak, así coma su carcasa, pechuga y proporciones resultaron mayores. La Pch se correlacionó alta y positivamente con el PV. Ninguna de las mediciones con calibre in vivo significó un aumento de consideración en la precisión de la predicción de Pch. En la experiencia 2 se utilizaron 60 pollos INTA-Camperos, muestreados al azar de un lote de 100 animales. A los 69 días de edad se realizaron mediciones in vivo del largo y ancho de la pechuga con calibre, y de la profundidad por ultrasonido previo a la faena, midiéndose los mismos parámetros que en la anterior experiencia. La correlación entre PV y la Pch fue alta y positiva, pero media a baja con las mediciones con calibre. Se obtuvo una buena predicción de Pch (R²=0,75 a partir del peso vivo, del largo y de la profundidad de pechuga. La eliminación de la medición ecográfica no redujo el ajuste del modelo de manera significativa (R²=0,725.
La Preparacion Fisica en el entrenamiento tecnico-tactico del Baloncesto
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Francisco Freyre Vázquez
2009-01-01
Full Text Available Se adaptó e introdujo todos los conceptos relacionados con la preparación física en el proceso general del entrenamiento de un equipo de baloncesto. Las propias características del juego, su complejidad en cuanto a las variables que influyen en el resultado, hizo necesario un planteamiento integrado del entrenamiento donde los ejercicios utilizados tuvieron un carácter complejo y afectando a todos los sistemas implicados en el entrenamiento (físico, técnico, táctico,¿, es decir, se expuso cómo utilizar todos los conceptos relacionados con la preparación física en el entrenamiento día a día y cómo ir introduciendo los diferentes sistemas, medios, métodos así como las diferentes cualidades físicas necesarias en las sesiones diarias de entrenamiento y en las diferentes fases de competición.
Pauli, Wolfgang
2007-01-01
Questo libro, curato da Pauli poco prima della morte, raccoglie un insieme di saggi che ben testimoniano la consapevolezza, che egli sempre ebbe vivissima, del significato più generale di ogni ricerca scientifica, valida non solo per il risultato singolo ma per il contributo più ampio al sapere. I saggi, percorsi dal tema comune del valore e dei limiti della conoscenza umana, possono essere distinti in due categorie: la prima puntualizza i personali apporti dell'autore e di altri grandi fisici alla scienza contemporanea; la seconda è dedicata a riflessioni sul potere del pensiero e alla validità di alcuni concetti fondamentali della teoria dell'evoluzione biologica e della psicologia dell'inconscio. Lo stile asciutto e rigoroso è animato dal ricordo personale di uomini ed episodi che fanno oggi parte della leggenda della fisica e, più in generale, della conoscenza umana.
Méndez, R
2002-01-01
"Estaba harto de escuchar lo dificil que es ensenar fisica, interesar a los alumnos en gases, tiros parabolicos y campos magneticos. Por eso el profesor de Fisica de la Universidad de Murcia Rafael Garcia Molina decidio hace cinco anos dejar sin argumentos a sus colegas. Comenzo la busqueda de juguetes, regalos y objetos cotidianos para explicar la fisica" (1 page).
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Maria Cimmino
2016-05-01
Full Text Available Lo sport, espressione di valori come la lealtà e la correttezza, il rispetto delle regole, l’integrazione, la democrazia, è una forma di manifestazione della personalità umana, finalizzata, anche attraverso il tempo libero, al miglioramento del benessere psicofisico del singolo e della collettività. Tuttavia e paradossalmente talvolta esso può risolversi nell’uso della violenza e/o in un contrasto fisico tra gli atleti, contemplato in alcuni casi dai regolamenti sportivi. Come si giunge a valutare meritevoli le attività sportive nel quadro dei diritti fondamentali della persona costituzionalmente garantiti? Il lavoro si propone di analizzare i rapporti tra diritto allo sport e diritto all’integrità fisica attraverso una rilettura della teoria giurisprudenziale del rischio consentito, giungendo alla conclusione che nel bilanciamento di interessi di pari rango costituzionale, l’organizzatore di competizioni sportive rivesta una fondamentale posizione di garanzia e che occorre modulare l’applicazione della clausola del rischio consentito in ragione delle circostanze del caso concreto e della qualità del soggetto e del carattere amatoriale od agonistico dell’attività.
1997-01-01
Un libro che mancava : attraverso i contributi dei maggiori specialisti italiani, la definizione rigorosa di una disciplina, la filosofia della fisica, che si pone nel punto d'incontro tra la cultura scientifica e quella umanistica.
Fisica Virgo, cosi' raccontera' origine universo
Battifogloia, E
2003-01-01
"Permettera' di avvicinarsi all'attimo del Big Bang con una precisione senza precedenti, l'antenna Virgo per le onde gravitazionali inaugurata oggi a Cascina, vicino Pisa, e nata da un progetto italo-francese coordinato dall'Istituto nazionale di Fisica Nucleare e dal Centro francese per le Ricerche Scientifiche" (1 page)
Il rumore elettrico Dalla fisica alla progettazione
Pallottino, Giovanni Vittorio
2011-01-01
L’opera fornisce una trattazione chiara, agile ed essenziale, ma completa, del rumore elettrico, argomento considerato generalmente oscuro e specialistico. Molto più breve (circa 275mila battute) dei testi attualmente disponibili. Il contenuto copre gli aspetti essenziali della matematica e della fisica del rumore (termico, shot. 1/f, …), e della sua rappresentazione nei circuiti. Discute quindi il rumore nei dispositivi passivi e attivi, e introduce i criteri di progettazione a basso rumore. Affronta infine brevemente questioni quali l’estrazione del segnale dal rumore e gli impieghi utili del rumore. L’attenzione è generalmente rivolta alla strumentazione fisica a bassa frequenza, in relazione alla pluridecennale esperienza specifica dell’autore. Si tratta di una estensione delle dispense, utilizzate per anni, di un corso universitario. Pertanto la trattazione è fortemente didattica, con particolare attenzione a rimuovere ambiguità e incertezze, discutendo il materiale in termini fisici intuit...
La macchina che cerca Dio. Nasce LHC forse scoprira' Higgs elusiva particella della creazione
Bianucci, P
2003-01-01
"LEON Lederman, premio Nobel per la fisica, l'ha misticamente definita la particella di Dio perche' sarebbe il pilastro sul quale si appoggia tutta la materia dell'universo che conosciamo. Piu' tecnicamente, e' la "particella di Higgs", un bosone previsto dal Modello Standard del microcosmo la cui esistenza sarebbe necessaria per giustificare, anche quantitativamente, la massa di tutte le particelle" (1/2 page).
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Víctor Hugo Durán Camelo
2012-12-01
Full Text Available El presente artículo tiene como propósito exponer la revisión inicial de antecedentes investigativos con miras a la formulación de tesis de grado, en el marco del Doctorado Interinstitucional en Educación de la Universidad Pedagógica Nacional, vinculando tres categorías de análisis: conocimiento profesional (CP, actividad física y desarrollo comunitario. Para dicha indagación se tuvo en cuenta la búsqueda documental en diferentes medios como: bases de datos especializadas (Redalyc, Eric y ProQuest, SciELO, etc., revistas académicas, libros, ampliación de bibliografía e investigaciones relevantes sobre el tema en mención. Los resultados indican, por una parte, la insuficiencia de producción académica que vincule las categorías señaladas; por otra parte, ubica los estudios sobre el CP principalmente en el ámbito escolar y, por ende, en docentes que desarrollan su labor en instituciones educativas, excluyendo el ámbito comunitario como un lugar para la comprensión e indagación sobre CP. Por lo tanto, se infiere que la presente revisión de antecedentes abre posibilidades investigativas para la producción de nuevo conocimiento, tanto en el campo del CP como el de la actividad física comunitaria.
Grippo, Maria Teresa
Il Modello Standard (MS) è la teoria scientifica più dibattuta degli ultimi anni nel mondo della fisica delle alte energie. Essa racchiude i fondamenti della materia e descrive le interazioni che regolano l'universo. Il MS è stato confermato in numerosi esperimenti, quali LEP e Tevatron, ma presenta ancora un ultimo interrogativo relativo all'origine della massa delle particelle. Il MS cerca di spiegare ciò tramite il meccanismo di Higgs, proposto da Peter Higgs nel 1964 \\cite{Higgs}: viene introdotta una nuova particella, chiamata \\emph{bosone di Higgs}, che ha lo scopo tramite il suddetto meccanismo di fornire massa alle particelle. Di tale particella non si conosce la massa, che viene infatti assunta come parametro libero della teoria. Scopo di tale lavoro di tesi è stato quello di studiare presso l'esperimento CMS (\\emph{Compact Muon Solenoid}) a LHC (\\emph{Large Hadron Collider}) il canale di produzione associata WH, nell'intervallo di massa 115 GeV/$c^{2} \\leq m_H \\leq $ 135 GeV/$c^{2}$, negli stat...
Bodei, Remo
2017-01-01
La Scuola della Cattedrale, presieduta da Monsignor Gianantonio Borgonovo, prosegue il suo ciclo di incontri con un evento culturale nel segno della fisica che esplora il mondo delle particelle. Guido Tonelli, fisico e professore ordinario dell’Università di Pisa, tratta degli eventi che hanno portato alla scoperta del bosone di Higgs al Cern di Ginevra dove è stato realizzato Lhc, l’acceleratore di particelle più potente del mondo, con un’analisi di materia e antimateria, energia e universo, per capire come tutto è cominciato e come forse andrà a finire. Dove potrà arrivare l’uomo con queste nuove visioni? Quali cambiamenti e traguardi sono ipotizzabili? Come leggere da un punto di vista religioso e filosofico questi nuovi scenari che la scienza prospetta? L’evento ha visto gli interventi di Monsignor Borgonovo e del filosofo Remo Bodei, professore emerito di Filosofia all’Università di Pisa.
Metodi matematici della fisica
Cicogna, Giampaolo
2015-01-01
Questo libro trae la sua origine dagli appunti preparati per le lezioni di Metodi Matematici della Fisica tenute al Dipartimento di Fisica dell'Università di Pisa, e via via sistemati, raffinati e aggiornati nel corso di molti anni di insegnamento. L'intento generale è di fornire una presentazione per quanto possibile semplice e diretta dei metodi matematici basilari e rilevanti per la Fisica. Anche allo scopo di mantenere questo testo entro i limiti di un manuale di dimensioni contenute e di agevole consultazione, sono stati spesso sacrificati i dettagli tecnici delle dimostrazioni matematiche (o anzi le dimostrazioni per intero) e anche i formalismi eccessivi, che tendono a nascondere la vera natura dei problemi. Al contrario, si è cercato di evidenziare – per quanto possibile – le idee sottostanti e le motivazioni che conducono ai diversi procedimenti. L'obiettivo principale e quello di mettere in condizione chi ha letto questo libro di acquisire gli strumenti adatti e le conoscenze di base che gli ...
Asimov, Isaac
1986-01-01
Isaac Asimov, illustre studioso e brillante divulgatore scientifico, ma anche grandissimo scrittore di science fiction, ha costruito questa volta una vera e propria «biografia delle scienze fisiche». Il presente volume, che nel mondo anglosassone è diventato una «bibbia della fisica», ci introduce, in forma semplice ma rigorosa, ai segreti dei quasar e dei buchi neri, dei quark e degli acceleratori di particelle, dell'intelligenza artificiale e delle fonti di energia, sia essa quella «sporca» sia quella «pulita». Un vero, completo manuale, ma anche un «romanzo» affascinante sia per il profano sia per l'uomo di scienza.
I grandi della fisica da Platone a Heisenberg
Von Weizsäcker, Carl Friedrich
2002-01-01
Parmenide ; Platone ; Aristotele ; Copernico, Keplero, Galilei ; Galileo Galilei ; Cartesio ; Gottfried Wilhelm Leibniz ; Cartesio, Newton, Leibniz, Kant ; Immanuel Kant ; Johann Wolfgang Goethe ; Robert Meyer ; Albert Einstein ; Niels Bohr ; Paul Adrien Maurice Dirac ; Niels Bohr e Werner Heisenberg, un ricordo del 1932 ; Werner Heisenberg ; Heisenberg, fisico e filosofo ; l'interpretazione filosofica della fisica moderna.
La fisica dell'universo iniziale
Maiani, Luciano
1994-01-01
1. Introduzione ; 2. Strutture ; 3. Il moto di Hubble e la connessione cosmica ; 4. Solo tre neutrini ; 5. Materia oscura ; 6. Le fluttuazioni del fondo cosmico ; 7. La rottura della simmetria e il bosone di Higgs ; 8. Il progetto LHC ; 9. Ancora sulla rottura della simmetria ; 10. Conclusioni.
La teoria della radiazione termica dalla fisica classica alla fisica quantistica
Planck, Max
1999-01-01
La venuta alla luce, nella scienza fisica dei primi anni del Novecento, di elementi assolutamente nuovi prefiguranti il futuro mondo quantistico, è concordemente attribuita all'opera prevalente di Planck e di Einstein, secondo due linee di ricerca profondamente diverse, anche se non lontane risultano le loro concezioni del mondo fisico. Tuttavia, mentre del secondo è facilmente accessibile e sufficientemente nota la produzione scientifica, del primo risulta ancora scarsamente sconosciuta l'ingente produzione di quegli anni, anche perché reperibile, per la maggior parte, solo in lingua originale. Se si tiene presente, inoltre, la comparsa in tempi recenti, della ricostruzione storiografica non tradizionale di T. Kuhn, che ritiene di cogliere, negli scritti di Planck, la permanenza di una struttura integralmente classica fino ad anni successivi al 1906, data di pubblicazione delle Lezioni, risulta naturale convenire sull'opportunità di rendere più agevole l'accesso alle fonti planckiane di quegli anni. ...
Astronomia e fisica a Firenze dalla Specola ad Arcetri
Bianchi, Simone; Casalbuoni, Roberto; Dominici, Daniele; Mazzoni, Massimo; Pelosi, Giuseppe
2017-01-01
La Mostra "Astronomia e Fisica a Firenze" illustra l'evoluzione delle due discipline dal XVIII secolo fino ai primi decenni del Novecento. Teatro cittadino di questo processo, anzi di tutte le scienze, fu l'Imperiale e Reale Museo di Fisica e Storia Naturale, dove adesso ha sede la Mostra. Nell'arco di tempo esaminato tutti gli aspetti dell'indagine della natura erano ugualmente pertinenti ad un'unica figura di studioso, ma verso l'inizio del XX secolo alcuni indirizzi subirono una profonda trasformazione e al prevalente approccio tassonomico e fenomenologico subentrò, soprattutto per Astronomia e Fisica, un'indagine specialistica che finì per differenziare le varie ricerche. Protagonista di questa fase fu lo sviluppo dell'analisi spettroscopica. La Mostra, aperta da dicembre 2016 a marzo 2017, è organizzata dall'Università di Firenze (Museo di Storia Naturale; Dipartimento di Fisica e Astronomia) e dall'Osservatorio Astrofisico di Arcetri, in collaborazione con la Sezione di Firenze dell'INFN, il Museo G...
Oltre lo spazio e il tempo la nuova fisica
Lachièze-Rey, Marc
2004-01-01
Oggi la fisica si fonda, allo stesso tempo, sulla meccanica quantistica e sulla relatività generale. Ma, in quanto veri e propri sistemi di pensiero, queste due teorie suggeriscono due distinte visioni del mondo, non conciliabili nel quadro di una descrizione unificata. Se dunque la fisica attuale si rivela inadeguata, occorre costruirne una nuova, percorrendo fino in fondo la via geometrica. Supersimmetria, stringhe e superstringhe, gravità e cosmologia quantistiche, geometria non commutativa: nuove audaci ipotesi al servizio di nuove teorie che rinnovano la nostra concezione dello spazio, del tempo, della materia e dell'Universo, e che trovano nel volume una presentazione chiara e accessibile anche a un pubblico di non specialisti.
L'evoluzione della fisica sviluppo delle idee dai concetti iniziali alla relatività e ai quanti
Einstein, Albert
1965-01-01
Pubblicato in inglese alla vigilia della Seconda guerra mondiale e subito proposto in traduzione, L’evoluzione della fisica dovette aspettare la fine del conflitto per vedere la sua pubblicazione in Italia. Da allora (1948) questo testo non ha più smesso di rappresentare un punto di riferimento obbligato per il concetto stesso di divulgazione scientifica e per la fisica in particolare. Scritto dai protagonisti assoluti della rivoluzione della fisica relativistica e quantistica, ma destinato a un pubblico di non specialisti, il libro che avete tra le mani è il testo fondativo della moderna divulgazione delle idee, la pietra di paragone di ogni altro libro di fisica, che permette di intuire la straordinaria importanza e il valore rivoluzionario della svolta della fisica del Novecento.
Diavolo di una particella perchè il bosone di Higgs cambierà la nostra vita
Menasce, Dario
2013-01-01
Lo scienziato del Cern Dario Menasce ha partecipato direttamente agli esperimenti che hanno condotto alla scoperta del Bosone di Higgs, ma , prima di condurre il lettore all'interno dell'LHC e dei suoi misteri, con coinvolgimento e grande serietà guida il lettore attraverso i momenti più importanti delle ricerche della fisica tramite l'intervento dei grandi scienziati del passato e del presente, che hanno infine permesso di arrivare a definire il Modello Standard delle particelle, il primo passo verso l'ipotetica Teoria del Tutto. Un testo molto utile per chi vuole sondare il mondo dell'ultrasottile, che riprendo in più occasioni anche come manuale di consultazione e approfondimento.
Lo sfondo filosofico della fisica moderna
Heisenberg, Werner
1999-01-01
Questa raccolta di saggi, inedita nella sua composizione e nuova in senso assoluto per l'Italia, presenta il pensiero di Heisenberg in tutta la sua articolazione e completezza: le riflessioni filosofiche fondamentali, le originali considerazioni epistemologiche, il credo etico-religioso, la visione della realtà e le due memorie scientifiche nelle quali venne elaborata la meccanica delle matrici, che fissò la nascita della cosiddetta «seconda quantistica», determinando la crisi della fisica classica e delineando l'orizzonte di senso da cui è derivato il successivo principio di indeterminazione. Emerge un pensatore che ha fornito contributi essenziali sia alla storia del pensiero filosofico che a quello scientifico del Novecento, e che ha rappresentato un vero e proprio «punto di svolta» della cultura contemporanea. Un punto di svolta che ha condotto il «metodo» della scienza dal gretto riduzionismo dell'epoca classica a una sua più concreta elaborazione in senso storicistico e complesso. Werner Heise...
Introduzione ai frattali in fisica
Ratti, Sergio Peppino
2011-01-01
La geometria frattale permette di caratterizzare le strutture complesse e irregolari che godono della proprietà di invarianza di scala. Introdotta da Mandelbrot nel 1975, spiega in modo convincente che la natura ci pone di fronte a molti esempi di strutture complesse che godono di proprietà peculiari: è un fatto che in natura l’irregolarità sia molto comune, come dimostrano le strutture di piante, montagne, nuvole e fulmini. Il volume nasce dall’esperienza didattica sviluppata dall’autore in oltre un decennio di insegnamento di Istituzioni di Fisica Superiore presso l’Università di Pavia e intende colmare la lacuna nel panorama italiano di testi didattici su tematiche frattali. Parte dalla definizione di oggetti e di funzioni frattali, introducendo la dimensione “non intera” e la “codimensione” di un insieme, di una figura geometrica e la sua estensione a una funzione matematica irregolare. Segue l’introduzione dei frattali stocastici che tengono conto della natura parzialmente caotica ...
Directory of Open Access Journals (Sweden)
Nancy Rodríguez Cabrera
2009-06-01
Full Text Available Nuestra investigación esta encaminada a la aplicación de un tratamiento físico del peso corporal en las mujeres obesas del consultorio 21 del Rpto. 5 de Septiembre del municipio Pinar del Río. Los ejercicios en las personas obesas son de gran importancia, puesto que conllevan a la disminución del peso corporal excesivo, sin dejar pasar por alto la dieta, que también contribuye al tratamiento de esta patología. Para ello aplicamos ejercicios con carácter aerobio de intensidad moderada tomando en cuenta la distribución topográfica en un período de un año. Se realizaron dos mediciones, un primero que nos permitió conocer el peso y estructura corporal de cada una de las muestras. Para ello tuvimos en cuenta el peso ideal, adecuado a la distribución topográfica a partir del índice cintura – cadera y se registró la talla o estatura de pie para el cálculo de IMC, estos datos permiten conocer el peso de la muestra, y su clasificación o grado de obesidad. Para la realización de nuestro trabajo utilizamos métodos teóricos y empíricos y como procedimiento estadístico empleamos el análisis porcentual, pudimos constatar la efectividad de la aplicación práctica del ejercicio físico, pues disminuyó el peso corporal de nuestros practicantes, acercándole cada vez más a su peso ideal.
Fondamenti di fisica dei plasmi
Golant, V E; Sacharov, I E
1983-01-01
Introduzione ; collisioni del plasma ; equazioni cinetiche per particelle cariche ; plasmi in equilibrio termodinamico ; funzione di distribuzione di particelle cariche in un campo elettrico ; equazioni dei momenti della funzione di distribuzione ; processi di trasporto nel plasma in assenza di campi magnetici ; moto di particelle cariche nel plasma in presenza di campi magnetici ; processi di trasporto in campo magnetico ; confinamento del plasma mediante campi magnetici.
Fisica atomica e quantistica introduzione ai fondamenti sperimentali e teorici
Haken, Hermann
1990-01-01
Per un laurea in Fisica, ma anche per la formazione moderna e aggiornata di un chimico o di un ingegnere, una conoscenza approfondita della fisica degli atomi e dei quanti è diventata ormai indispensabile....
Bianchi, U; Volta, L
Termodinamica ; cenni sulla costituzione della materia ; il metodo statistico ; le statistiche di Boltzmann-Maxwell, Bose-Einstein e Fermi-Dirac ; studio termodinamico e statistico del gas perfetto e delle miscele gassose ; i solidi cristallini ; le reazioni chimiche.
Dai buchi neri all’adroterapia un viaggio nella fisica moderna
Curceanu, Catalina Oana
2013-01-01
Tutto quello che avreste voluto sapere sulla fisica moderna ma non avevate nessuno a cui chiederlo! Questo libro vi conduce in un viaggio affascinante attraverso i misteri della fisica moderna e delle sue tantissime ricadute nella società, presentando anche le ricerche attualissime, le strade che si aprono davanti a noi: a volte ampi viali illuminati a giorno, altre volte sentieri appena accennati. Dove ci porteranno? La grande forza della scienza, nonché il suo motore, è la curiosità che ci ha spinto a guardare in alto, in profondità ma anche dentro noi stessi. Indagando abbiamo trovato veri tesori. La fisica ci spiega cosa succede nell’atomo ma anche nell’Universo, un mondo che va dal miliardesimo di miliardesimo di metro a una decina di miliardi di anni luce! Abbiamo una spiegazione razionale non soltanto a domande del tipo “di cosa è fatto il mondo?”, ma anche a domande molto più difficili: “come è nato l’Universo e come potrebbe evolversi?”. La fisica fondamentale ha anche enormi ri...
Esercizi di fisica meccanica e termodinamica
Dalba, G
2006-01-01
La risoluzione di esercizi rappresenta uno strumento indispensabile per raggiungere una comprensione sicura e approfondita dei concetti di Fisica appresi dai corsi e dai testi di teoria. Frutto di una lunga esperienza didattica dei due autori nell'insegnamento universitario della meccanica e della termodinamica, questa raccolta contiene 188 esercizi, di cui 91 completamente risolti ed accompagnati da un ampio corredo di figure. Il peimo capitolo presenta un'introduzione ai sistemi di unitÃ di misura, al calcolo dimensionale, all'uso corretto delle cifre significative e degli arrotondamenti, ai grafici. Gli altri capitoli contengono gli esercizi, suddivisi per argomento e preceduti da una serie di paragrafi riassuntivi dei concetti fondamentali. Criterio ispiratore di questo lavoro Ã¨ l'adozione di una metodologia per la soluzione degli esercizi basata sempre sull'analisi accurata dei dati a disposizione e sul riferimento ai principi e alle leggi della Fisica, mai alla sola intuizione.
La fisica dell'immortalità Dio, la cosmologia e la resurrezione dei morti
Tipler, Frank J
1995-01-01
“Questo libro descrive la teoria del Punto Omega: la teoria fisica e sperimentale di un Dio onnipresente onniscente e onnipotente, che in un giorno del futuro remoto farà risorgere ciascuno di noi alla vita eterna in una dimora che per ogni aspetto fondamentale è il paradiso della tradizione ebraico-cristiana. I singoli termini delle teoria – per esempio i concetti di onnipresenza, onniscienza, onnipotenza, corpo (spirituale) risuscitato, paradiso – saranno presentati come principi della fisica pura. In questo libro non farò mai appello alla rivelazione; mi appellerò, invece, ai risultati concreti della scienza moderna e alla ragione del lettore. Descriverò il meccanismo fisico della risurrezione universale. Mostrerò con estrema precisione come la fisica consenta la risurrezione alla vita eterna di tutti coloro che sono vissuti, che vivano o che vivranno. E mostrerò anche perché, nel futuro remoto, tale facoltà di risuscitare esisterà davvero e perché sarà effettivamente usata. A chi ha perd...
"El programa del CERN está diseñado para que no se nos escape el Higgs"
Rivera, Alicia
2000-01-01
Luciano Maiani, italian physicst assumes the direction of CERN. The aim in CERN is now to find the Higgs boson, and a week ago, some indications that could be interpretaded as signs have been discovered (2 pages)
Fisica e filosofia come la scienza contemporanea ha modificato il pensiero dell'uomo
Heisenberg, Werner
2003-01-01
Nel corso del Novecento le scoperte della fisica – dalla meccanica quantistica alla teoria della relatività, dalle ricerche sul cosmo all’energia nucleare – hanno travolto le precedenti nozioni di spazio e tempo e rivoluzionato la percezione che l’uomo aveva di sé, investendolo inoltre della responsabilità di una possibile autodistruzione. Figura geniale e controversa, Werner Heisenberg è stato un protagonista assoluto dell’epopea scientifica del secolo scorso, insieme a Bohr e Fermi, Einstein e Planck. Fisica e filosofia esplora la complessità di quello snodo offrendo risposte chiare a domande che non hanno mai perso la loro centralità. Cosa affermano le teorie della fisica contemporanea? In che modo investono la concezione che l’uomo ha di sé? Quali sono i limiti etici delle loro applicazioni tecnologiche? E quale sarà l’influenza politica della scienza su scala planetaria? Affrontando quesiti di portata universale, Heisenberg si dimostra consapevole della necessità di ristabilire la ...
Hemmer, Sabine
2018-01-01
Poster di ATLAS sul bosone di Higgs indirizzato al pubblico generico, che spiega il meccanismo di Brout-Englert-Higgs e la sua importanza. Spiega anche il ruolo del Bosone di Higgs, come viene cercato, il percorso della sua scoperta e cosa viene dopo la scoperta. Disponibile anche in Francese (http://cds.cern.ch/record/1697501) e Inglese (http://cds.cern.ch/record/1697389). Non esitate a utilizzarlo nelle sedi dei vostri Istituti e negli eventi divulgativi! Il poster è in formato A0. Cliccate sull'immagine per scaricare il .pdf ad alta qualità e stamparlo dove preferite. Per qualisasi domanda o commento potete contattare atlas-outreach-coordination@cern.ch
Energy Technology Data Exchange (ETDEWEB)
Passarino, Giampiero [Universita di Torino, Dipartimento di Fisica Teorica, Turin (Italy); INFN, Sezione di Torino, Turin (Italy)
2014-05-15
Higgs Computed Axial Tomography, an excerpt. The Higgs boson lineshape (..and the devil hath power to assume a pleasing shape, Hamlet, Act II, scene 2) is analyzed for the gg → ZZ process, with special emphasis on the off-shell tail which shows up for large values of the Higgs virtuality. The effect of including background and interference is also discussed. The main focus of this work is on residual theoretical uncertainties, discussing how much-improved constraint on the Higgs intrinsic width can be revealed by an improved approach to analysis. (orig.)
International Nuclear Information System (INIS)
Passarino, Giampiero
2014-01-01
Higgs Computed Axial Tomography, an excerpt. The Higgs boson lineshape (..and the devil hath power to assume a pleasing shape, Hamlet, Act II, scene 2) is analyzed for the gg → ZZ process, with special emphasis on the off-shell tail which shows up for large values of the Higgs virtuality. The effect of including background and interference is also discussed. The main focus of this work is on residual theoretical uncertainties, discussing how much-improved constraint on the Higgs intrinsic width can be revealed by an improved approach to analysis. (orig.)
Fracas, Fabio
2017-01-01
Questo libro è un'avventura esclusiva e affascinante. Un viaggio, anche nel tempo, alla scoperta di qualcosa di nuovo e di straordinario: la Fisica Quantistica, nelle sue logiche, nelle sue potenzialità, nelle sue applicazioni e nei suoi possibili sviluppi. All'interno del volume vengono ricostruiti passo dopo passo i momenti fondamentali del pensiero quantistico, le questioni su cui si sono interrogati i più grandi scienziati degli ultimi decenni, e i diversi contesti nei quali si sono evoluti i principali modelli della Meccanica Quantistica. Sullo sfondo delle ricerche più attuali - come per esempio quella sulle onde gravitazionali che ha portato al Nobel per la Fisica 2017 -, vengono indagati anche i rapporti esistenti fra Fisica Quantistica, Relatività Einsteiniana e Teoria delle Stringhe. Inoltre, fra i tanti temi trattati nelle sue pagine, trovano spazio persino le incredibili ricadute che gli studi sulla Fisica Quantistica stanno avendo negli ambiti della medicina e delle ricerche sul cervello e s...
Indian Academy of Sciences (India)
The theoretical aspects of the physics of Higgs bosons are reviewed focussing on the elements that are relevant for the production and detection at present hadron colliders. After briefly summarizing the basics of electroweak symmetry breaking in the Standard Model, the Higgs production at the LHC and at the Tevatron is ...
International Nuclear Information System (INIS)
Rindani, Saurabh D.
2002-07-01
Higgs physics is at present poised at an interesting juncture, when a light Higgs boson of the standard model (henceforth to be referred to as SM), a spin-zero particle which would signal spontaneous gauge symmetry breaking in the simplest form, has not been seen until the conclusion of experiments at LEP and LEP2 electron-positron collider at CERN, Geneva. From a theoretical point of view, the developments until the present time are complex and interesting. While some of the basic principles underlying spontaneous symmetry breaking of gauge symmetry and the Higgs mechanism are now commonly known, the actual realization of this mechanism in nature is still a subject of investigation. The mass of the SM Higgs boson is an unknown parameter and the phenomenology is sensitively dependent on the mass. Thus the properties and discovery strategies for the Higgs vary greatly depending on the supposed mass, and the phenomenology rapidly gets complex as the range of the Higgs mass is increased. Branching rations for various channels and the total decay width are shown as a function of the Higgs mass. We can get the total width of the Higgs by adding up all the decay channels. Up to masses of about 140 GeV, the Higgs is very narrow, Γ(H) H ∼ 200 GeV. The width cannot be measured directly in the intermediate mass region at LHC or e + e - colliders. However, it could be measured at μ + μ - colliders. Above a mass of about 250 GeV, the state is wide enough to be observable, in general. Above the two-vector-boson threshold, the width is Γ(H) ∼ 1/2m H 3 (TeV). For m H ∼ 1 TeV, Γ H ∼ 1/2 TeV. (author)
Directory of Open Access Journals (Sweden)
G. Capelli
2003-05-01
Full Text Available
Obiettivi: l’associazione fra stato socio-economico (SES ed attività fisica è poco indagata. Obiettivo del presente studio è quello di valutare la relazione tra attività fisica extra-scolastica di adolescenti scolarizzati e lo SES della famiglia di provenienza.
Metodi: l’indagine ha previsto la somministrazione nel corso dell’anno scolastico 2002-2003 di un apposito questionario anonimo autocompilato, già validato in uno studio pilota, ad un campione di studenti delle scuole medie inferiori del Lazio (province di Roma, Frosinone e Latina.
Risultati: hanno partecipato allo studio 1486 studenti di cui 756 maschi (50.9% e 730 femmine (49.1%. L’età dei partecipanti varia fra gli 11 ed i 15 anni (età mediana 12 anni. Il 72.7% degli studenti dichiara di svolgere attività fisica al di fuori della scuola. Il livello di istruzione dei genitori e la loro attività lavorativa sembrano avere un peso notevole sui determinanti dell’attività fisica negli studenti. Infatti, svolgono prevalentemente attività fisica extra-scolastica i figli di genitori manager/libero professionisti (OR = 3.29 e con un elevato livello educativo (OR = 10.38 per i figli di genitori laureati.
Conclusioni: i risultati confermano quanto la situazione socio-economica delle famiglie sia in netta relazione con l’attività fisico-sportiva dei giovani. Tali risultati potranno essere utili per gli operatori scolastici e gli amministratori nell’ispirare e realizzare azioni volte a diminuire il divario esistente fra i giovani che hanno le possibilità economiche e svolgono attività sportiva extra-scolastica e quelli che, invece, appartenendo a famiglie svantaggiate, hanno minore accesso a tali attività.
Woit, Peter
2007-01-01
La teoria delle stringhe, "eterna promessa" della fisica teorica, sembra oggi giunta alla resa dei conti, e molti studiosi si stanno da tempo interrogando sulla sua reale validità. Un certo malcontento già serpeggiava nei corridoi delle università e in alcuni scritti quasi clandestini ma ora giunge dagli Stati Uniti la voce di Peter Woit, ferma e decisa nel lanciare un messaggio chiaro: questa presunta "teoria del tutto" che pretendeva di unificare le leggi della fisica, si è rivelata alla fine una "teoria del niente", incapace di dimostrare anche uno solo dei suoi enunciati. Dopo una dettagliata panoramica sugli sviluppi della fisica che hanno portato, nella metà degli anni Settanta, alla nascita e al successo del Modello standard, Woit giunge quindi al cuore del suo libro. L'accusa è pesante: non solo i teorici delle stringhe non fanno scienza, ma hanno goduto di un predominio eccessivo per vent'anni, monopolizzando il reperimento dei fondi economici pubblici e privati e impedendo di fatto un sano pro...
DEFF Research Database (Denmark)
Sannino, Francesco
2013-01-01
has been challenged by the discovery of a not-so-heavy Higgs-like state. I will therefore review the recent discovery \\cite{Foadi:2012bb} that the standard model top-induced radiative corrections naturally reduce the intrinsic non-perturbative mass of the composite Higgs state towards the desired...... via first principle lattice simulations with encouraging results. The new findings show that the recent naive claims made about new strong dynamics at the electroweak scale being disfavoured by the discovery of a not-so-heavy composite Higgs are unwarranted. I will then introduce the more speculative......I discuss the impact of the discovery of a Higgs-like state on composite dynamics starting by critically examining the reasons in favour of either an elementary or composite nature of this state. Accepting the standard model interpretation I re-address the standard model vacuum stability within...
Mercenario della ricerca evoluzione dello studioso di fisica tra il 1900 e il 2000
Sironi, Giorgio
2015-01-01
In meno di un secolo la percezione della ricerca da parte del grande pubblico e il modo di praticarla sono profondamente cambiati. Il ricercatore, non più isolato e parte di una élite ristretta, oggi è quasi sempre inserito in gruppi strutturati, spesso numerosi. Questa impostazione, particolamente evidente in Fisica e Astrofisica, ha prodotto grandi progressi scientifici. In Italia però questi progressi rischiano di essere vanificati dalla perdurante mancanza di politiche organiche dedicate alla ricerca, sia pubblica che privata. Per un giovane dotato vale ancora la pena di puntare a fare ricerca?
Energy Technology Data Exchange (ETDEWEB)
Campise, A. V. [Atomics International, Canoga Park, CA (United States)
1962-03-15
'etude de cet ensemble a mis en relief l'importance des donnees relatives aux sections efficaces et de l'interpretation theorique des resultats experimentaux pour l'etude d'un reacteur au thorium de type perfectionne. La precision des methodes analytiques employees a ete demontree lors de l'analyse des resultats experimentaux obtenus avec le ZPR-III. L'auteur compare trois configurations pour le transfert de chaleur, en utilisant le temps de doublement comme parametre d'optimisation. Les effets de la production de {sup 233}Pa et d'isotopes de l'uranium sur le bilan neutronique, les taux possibles de surgeneration et les caracteristiques de la combustion sont evalues en tenant compte de l'imprecision des sections efficaces nucleaires. (author) [Spanish] El autor estudia la concepcion del reactor AETR desde el punto de vista de la teoria actual de los parametros nucleares y del balance neutronico. En los sistemas moderados por grafito examina el efecto de la captura por resonancia en el torio para energias medias de absorcion del orden de 0,10 a 100 keV. Aplica formulas de resonancia angosta y de resonancia ancha para obtener la integral de resonancia efectiva en funcion de la temperatura, correspondiente a las barras de torio, y dicho parametro se expresa como secciones eficaces equivalentes de varios grupos. Se ha disenado y construido un conjunto critico para obtener datos nucleares indispensables en la gama de energias intermedias. En el diseno nuclear de dicho conjunto, se ha tenido particularmente en cuenta la importancia de los datos relativos a secciones eficaces y la interpretacion teorica de estos resultados experimentales, cosas ambas relacionadas con el diseno del reactor AETR. La precision de los metodos analiticos ha quedado demostrada por el estudio de los resultados experimentales obtenidos con el reactor ZPR-III. Se comparan tres sistemas de transmision de calor utilizando el tiempo de duplicacion como parametro optimo. Se estudia el efecto de la formacion
Search for Charged Higgs in CDF
CDF Collaboration
1996-05-01
We present results of a search for charged Higgs production from pbarp collisions at √s=1.8 TeV at Fermilab's Tevatron collider using the CDF detector. An expanded Higgs sector containing charged Higgs bosons is a persistent feature of candidate theories to replace the Standard Model. The minimal supersymmetric extention of the Standard Model, for example, predicts that the dominant decay mode of the top quark is tarrow H+barrow τ+ν b for large values of tanβ. We use the hadronic decays of the tau lepton in this channel to set a new limit on charged Higgs production. *We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Science and Culture of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; and the A. P. Sloan Foundation. Supported by U.S. NSF NSF-94-17820.
Pomarol, Alex
2016-01-01
With the discovery of the Higgs, we have access to a plethora of new physical processes that allow us to further test the SM and beyond. We show a convenient way to parametrize these physics using an effective theory for Higgs couplings, discussing the importance of the basis selection, predictions from a SM effective field theory, and possible ways to measure these couplings with special attention to the high-energy regime. Predictions from the MSSM and MCHM, with the comparison with data, are also provided.
Grojean, C.
2016-01-01
The cause of the screening of the weak interactions at long distances puzzled the high-energy community for more nearly half a century. With the discovery of the Higgs boson a new era started with direct experimental information on the physics behind the breaking of the electroweak symmetry. This breaking plays a fundamental role in our understanding of particle physics and sits at the high-energy frontier beyond which we expect new physics that supersedes the Standard Model. The Higgs boson (inclusive and differential) production and decay rates offer a new way to probe this frontier.
Phenomenology of Higgs particles
International Nuclear Information System (INIS)
Jarlskog, C.; Stockholm Univ.
1985-01-01
These lecture notes are organized as follows: 1. Introduction, 2. Interactions and decay modes of the Standard Higgs phisub(O), 3. Nonstandard Higgs multiplets, 4. Upper limits on the Higgs mass, 5. Lower limits on the Higgs mass, 6. Production mechanisms for the Standard Higgs, 7. Outlook. (orig.)
Rajantie, Arttu
2018-03-06
The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).
Rajantie, Arttu
2018-01-01
The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available. This article is part of the Theo Murphy meeting issue `Higgs cosmology'.
Veltman, Martinus J. G.
1986-01-01
Reports recent findings related to the particle Higgs boson and examines its possible contribution to the standard mode of elementary processes. Critically explores the strengths and uncertainties of the Higgs boson and proposed Higgs field. (ML)
Lezioni di fisica teorica meccanica quantistica
Verde, Mario
Ottica geometrica ed ottica ondulatoria ; risoluzion spettrale di Fourier ; meccanica classica e meccanica ondulatoria ; esempi di alcuni moti semplici in meccanica ondulatoria ; operatori lineari e loro rappresentazioni ; formulazione più generale della nuova meccanica ; costanti del movimento ; l'atomo di Idrogeno ; teoria delle perturbazioni.
Topological Higgs mechanism with ordinary Higgs mechanism
International Nuclear Information System (INIS)
Oda Ichiro; Yahikozawa Shigeaki.
1989-12-01
Topological Higgs mechanism in higher dimensions is analyzed when ordinary Higgs potential exists. It is shown that if one-form B-field becomes massive by the ordinary Higgs mechanism, another D-2 form C-field also becomes massive through topological term in addition to the topological mass generation by the topological Higgs mechanism. Moreover we investigate this mechanism in three dimensional theories, that is to say, Chern-Simons theory and more general theory. (author). 10 refs
Fisica per poeti lo scienziato come uomo e artista : storia della fisica da Galileo ai giorni nostri
March, Robert H
1994-01-01
Un'intensa lezione di oggettività scientifica attraverso i secoli, alla ricerca delle verità ultime della natura. Da Galileo ad oggi, intuizioni, errori, grandi scoperte dei massimi protagonisti della fisica classica e moderna: la scienza vissuta come un'appassionante avventura.
Unal, G
2006-01-01
This is a review of Higgs physics at LHC. The topics covered are the search of the Standard Model Higgs boson (with emphasis on the low mass region), the measurements of the Higgs boson properties (mass, width, spin, CP and couplings) and the Higgs sector of the MSSM.
Directory of Open Access Journals (Sweden)
Jonás Valencia Carrillo
2016-01-01
Full Text Available Se explica de forma didáctica, accesible para profesores que imparten los cursos de física moderna básica, el mecanismo del rompimiento espontáneo de la sime - tría con la presencia de un campo de Higgs. Para conseguir este objetivo, se desarrolla un modelo matemático basado en el comportamiento de resortes que obedecen a las leyes del oscilador armónico simple y con la presencia de cargas que oscilan junto con éstos. Como resultado, se obtiene que la luz emitida por las cargas oscilantes, los fotones, duplican su masa cuando los resortes se deforman más allá de su límite elástico debido a la presencia de una fuerza externa que rompe la simetría inicial del sistema.
International Nuclear Information System (INIS)
Chen, Xin
2016-01-01
The updated Higgs measurements in various search channels with ATLAS Run 1 data are reviewed. Both the Standard Model (SM) Higgs results, such as H → γγ, ZZ, WW, ττ, μμ, bb-bar, and Beyond Standard Model (BSM) results, such as the charged Higgs, Higgs invisible decay and tensor couplings, are summarized. Prospects for future Higgs searches are briefly discussed
Introduzione al laboratorio di fisica misure e teoria delle incertezze
Ciullo, Giuseppe
2014-01-01
Frutto dell'esperienza decennale come supporto per la didattica di laboratori di fisica sia a livello di corsi triennali che di corsi di laurea magistrale, il libro si è concretizzato nella "responsabilità" di tali corsi di laboratorio per fornire un opera di utilizzo dei vari strumenti, che un approccio sperimentale alla fisica richiede. Si parte dalla descrizione delle problematiche delle incertezze in modo operativo e si introducono i concetti fondamentali per l'analisi dei dati e la misura. Invece di una serie dispersiva di testi, con approcci, convenzioni e simbolismi differenti, poco fruibili per l'applicazione diretta ad un laboratorio dei primi anni, il libro fornisce le indicazioni utili per affrontare lo studio dei fenomeni fisici in modo immediato, fornendo anche indicazioni rigorose e giustificazioni teoriche. Lo stimolo teorico-pratico, che uno sperimentale-scienziato deve percepire, non esula dal comprendere problematiche di maggiore approfondimento. L'opera rende fruibili concetti e strumenti...
Asner, D.M.; Calancha, C.; Fujii, K.; Graf, N.; Haber, H.E.; Ishikawa, A.; Kanemura, S.; Kawada, S.; Kurata, M.; Miyamoto, A.; Neal, H.; Ono, H.; Potter, C.; Strube, J.; Suehara, T.; Tanabe, T.; Tian, J.; Tsumura, J.; Watanuki, S.; Weiglein, G.; Yagyu, K.; Yokoya, H.
2013-01-01
The ILC Higgs White Paper is a review of Higgs Boson theory and experiment at the International Linear Collider (ILC). Theory topics include the Standard Model Higgs, the two-Higgs doublet model, alternative approaches to electroweak symmetry breaking, and precision goals for Higgs boson experiments. Experimental topics include the measurement of the Higgs cross section times branching ratio for various Higgs decay modes at ILC center of mass energies of 250, 500, and 1000 GeV, and the extraction of Higgs couplings and the total Higgs width from these measurements. Luminosity scenarios based on the ILC TDR machine design are used throughout. The gamma-gamma collider option at the ILC is also discussed.
Sperimentare e simulare la fisica attraverso la manipolazione e l’uso di tecnologie didattiche
Directory of Open Access Journals (Sweden)
Eugenia Lucia Bossio
2013-03-01
Full Text Available Nell'ambito di una ricerca volta a investigare la possibilità di presentare la teoria del caos, un tema della fisica assai ostico per i non specialisti, a studenti di scuole medie e superiori, sono stati sviluppati e raccolti una serie di materiali didattici. Il presente lavoro descrive gli strumenti utilizzati per le sperimentazioni nelle scuole descritte in un altro articolo1 contenuto in questo stesso numero della rivista. Le tematiche scientifiche sono state poste sotto una veste accattivante al fine di suscitare curiosità. Si è provveduto, inoltre, a strutturare i materiali didattici in maniera da proporre dei percorsi formativi poliedrici e diversificati anche tramite l'uso delle tecnologie informatiche. Lo sviluppo e la raccolta di applicativi multimediali, facilmente reperibili in rete, ha contribuito alla realizzazione di un pacchetto di strumenti che, nel suo insieme, consente un’applicazione didattica efficace realizzata più volte nel corso delle sperimentazioni compiute presso le scuole. Nel seguito saranno descritti gli elementi elettrici ed elettronici per la costruzione di un circuito elettronico che mostra un comportamento caotico e le varie operazioni necessarie per realizzarlo, gli strumenti informatici utili per la visualizzazione, su di un calcolatore, del segnale di tensione prodotto dal circuito, infine, i diversi software attraverso cui è possibile realizzare la simulazione del circuito elettronico e la visualizzazione delle traiettorie caotiche. Sono presentati, infine, i test di verifica e alcuni altri materiali didattici utilizzati durante le sperimentazioni già realizzate.
Energy Technology Data Exchange (ETDEWEB)
Holzner, André G., E-mail: andre.georg.holzner@cern.ch [University of California at San Diego (United States); Collaboration: on behalf of the CMS collaboration
2016-12-15
This article reviews recent measurements of the properties of the standard model (SM) Higgs boson using data recorded with the CMS detector at the LHC: its mass, width and couplings to other SM particles. We also summarise highlights from searches for new physical phenomena in the Higgs sector as they are proposed in many extensions of the SM: flavour violating and invisible decay modes, resonances decaying into Higgs bosons and searches for additional Higgs bosons.
Smart, Ben; The ATLAS collaboration
2017-01-01
The High-Luminosity LHC will prove a challenging environment to work in, with for example $=200$ expected. It will however also provide great opportunities for advancing studies of the Higgs boson. The ATLAS detector will be upgraded, and Higgs prospects analyses have been performed to assess the reach of ATLAS Higgs studies in the HL-LHC era. These analyses are presented, as are Run-2 ATLAS di-Higgs analyses for comparison.
Gunion, John F; Haber, Howard E; Kane, Gordon L
1989-01-01
The Higgs Hunter's Guide is a definitive and comprehensive guide to the physics of Higgs bosons. In particular, it discusses the extended Higgs sectors required by those recent theoretical approaches that go beyond the Standard Model, including supersymmetry and superstring-inspired models.
Geller, Michael; Telem, Ofri
2015-05-15
We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.
Geller, Michael; Telem, Ofri
2015-05-01
We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at mKK , naturally allowing for mKK beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.
DEFF Research Database (Denmark)
Giardino, P. P.; Kannike, K.; Masina, I.
2014-01-01
We perform a state-of-the-art global fit to all Higgs data. We synthesise them into a 'universal' form, which allows to easily test any desired model. We apply the proposed methodology to extract from data the Higgs branching ratios, production cross sections, couplings and to analyse composite...... Higgs models, models with extra Higgs doublets, supersymmetry, extra particles in the loops, anomalous top couplings, and invisible Higgs decays into Dark Matter. Best fit regions lie around the Standard Model predictions and are well approximated by our 'universal' fit. Latest data exclude the dilaton...... as an alternative to the Higgs, and disfavour fits with negative Yukawa couplings. We derive for the first time the SM Higgs boson mass from the measured rates, rather than from the peak positions, obtaining M-h = 124.4 +/- 1.6 GeV....
Giudice, Gian F
2011-01-01
We consider a simple extension of the Standard Model Higgs inflation with one new real scalar field which preserves unitarity up to the Planck scale. The new scalar field (called sigma) completes in the ultraviolet the theory of Higgs inflation by linearizing the Higgs kinetic term in the Einstein frame, just as the non-linear sigma model is unitarized into its linear version. The unitarity cutoff of the effective theory, obtained by integrating out the sigma field, varies with the background value of the Higgs field. In our setup, both the Higgs field and the sigma field participate in the inflationary dynamics, following the flat direction of the potential. We obtain the same slow-roll parameters and spectral index as in the original Higgs inflation but we find that the Hubble rate during inflation depends not only on the Higgs self-coupling, but also on the unknown couplings of the sigma field.
International Nuclear Information System (INIS)
Giudice, Gian F.; Lee, Hyun Min
2011-01-01
We consider a simple extension of the Standard Model Higgs inflation with one new real scalar field which preserves unitarity up to the Planck scale. The new scalar field (called sigma) completes in the ultraviolet the theory of Higgs inflation by linearizing the Higgs kinetic term in the Einstein frame, just as the non-linear sigma model is unitarized into its linear version. The unitarity cutoff of the effective theory, obtained by integrating out the sigma field, varies with the background value of the Higgs field. In our setup, both the Higgs field and the sigma field participate in the inflationary dynamics, following the flat direction of the potential. We obtain the same slow-roll parameters and spectral index as in the original Higgs inflation but we find that the Hubble rate during inflation depends not only on the Higgs self-coupling, but also on the unknown couplings of the sigma field.
Energy Technology Data Exchange (ETDEWEB)
Vargas-Meleza, L.; Valle-Molina, C. [Instituto Mexicano del Petroleo (Mexico)]. E-mails: lvargasm@imp.mx; cvallem@imp.mx
2012-10-15
Integration of the geological and geophysical information with different scale and features is the key point to establish relationships between petrophysical and elastic characteristics of the rocks in the reservoir. It is very important to present the fundamentals and current methodologies of the rock physics analyses applied to hydrocarbons exploration among engineers and Mexican students. This work represents an effort to capacitate personnel of oil exploration through the revision of the subjects of rock physics. The main aim is to show updated improvements and applications of rock physics into seismology for exploration. Most of the methodologies presented in this document are related to the study the physical and geological mechanisms that impact on the elastic properties of the rock reservoirs based on rock specimens characterization and geophysical borehole information. Predictions of the rock properties (lithology, porosity, fluid in the voids) can be performed using 3D seismic data that shall be properly calibrated with experimental measurements in rock cores and seismic well log data. [Spanish] Se discuten los fundamentos de fisica de rocas y las implicaciones analiticas para interpretacion sismica de yacimientos. Se considera conveniente difundir, entre los ingenieros y estudiantes mexicanos, los fundamentos y metodologias actuales sobre el analisis de la fisica de rocas en exploracion de hidrocarburos. Este trabajo representa un esfuerzo de capacitacion profesional en exploracion petrolera en el que se difunde la relevancia de la fisica de rocas. El interes principal es exponer los avances tecnologicos y aplicaciones actuales sobre fisica de rocas en el campo de sismologia de exploracion. La mayoria de las metodologias estudia los mecanismos fisicos y geologicos que controlan las propiedades elasticas de los yacimientos de hidrocarburos, a partir de nucleos de roca y registros geofisicos de pozo. Este conocimiento se usa para predecir propiedades de la
VII Workshop Italiano sulla fisica pp a LHC
LHCpp2016 è la settima edizione dell'incontro nazionale sulla fisica p-p a LHC. Questa serie di incontri è nata a Pisa nel 2003 con lo scopo di stimolare lo scambio di idee tra le comunità sperimentali di ATLAS, CMS e LHCB e la comunità teorica. Caratteristica fondamentale di questi incontri è la preparazione di larga parte dei talk in collaborazione tra i vari esperimenti e la comunità teorica. Largo spazio nella preparazione e presentazione dei talk viene dato ai giovani ricercatori. In questa settima edizione, che si tiene di nuovo a Pisa, vogliamo concentrare l'attenzione sulle potenzialità di scoperta offerte dai dati raccolti durante il runII di LHC.
Il mondo dei quanti la fisica quantistica per tutti
Ford, Kenneth W
2006-01-01
L'autore spiega come le leggi che governano l'enormemente piccolo e l'enormemente rapido sfidino il senso comune e mettano alla prova l'intelletto al limite delle sue possibilità. Ford introduce alle grandi idee di una teoria - la fisica quantistica - che continua a rimanere misteriosa nonostante i numerosi successi: la granularità (la materia e alcune sue proprietà, come l'energia, sono "grumose"), il dualismo onda-particella, il principio di indeterminazione, la natura dei bosoni e dei fermioni, il principio di sovrapposizione e la non separabilità (il fatto che un atomo possa trovarsi simultaneamente in due o più stati di moto diversi).
International Nuclear Information System (INIS)
Dawson, S.; Haber, H.E.; Rindani, S.D.
1989-05-01
This is the summary report of the Higgs Boson Working Group. We discuss a variety of search techniques for a Higgs boson which is lighter than the Z. The processes K → πH, η prime → ηH,Υ → Hγ and e + e - → ZH are examined with particular attention paid to theoretical uncertainties in the calculations. We also briefly examine new features of Higgs phenomenology in a model which contains Higgs triplets as well as the usual doublet of scalar fields. 33 refs., 6 figs., 1 tab
Gonzalez Suarez, Rebeca; Rodrigo Anoro, Teresa
2010-01-01
A prospective analysis for the search of a SM Higgs boson in the Compact Muon Solenoid (CMS) experiment at the LHC is performed in this thesis, focusing in the gg → H → WW∗ → μνμν process. The search channel has a clear signature characterized by the presence of two high PT muons in the final state and a significant amount of missing ET due to the undetected neutrinos. No hard jet activity is expected. The principal sources of background come from several SM processes that may have similar final states as those of the signal, mainly W + jets, Z + jets, tt and the almost irreducible WW. Other sources of background are WZ, ZZ and tW processes. Final states coming from QCD processes have different signatures but very large cross-sections and they have also been studied. Several analysis techniques have been developed in this work. The main one is based on the application of a sequential selection criteria using a set of physical observables which characterize the main kinematic properties of the sign...
2008-01-01
Quantum physicists think they know the answer. Probabilistic calculations reveal than the data provided by previous experiments has been miscalculated and that the Higgs boson has in fact been discovered. Weird! The Higgs boson is the only particle predicted by the Standard Model that hasn't been discovered yet.
Stefania Pandolfi
2016-01-01
CERN celebrated the fourth anniversary of the historical Higgs boson announcement with special pizzas. 400 pizzas were served on Higgs pizza day in Restaurant 1 at CERN to celebrate the fourth anniversary of the announcement of the discovery of the Higgs Boson (Image: Maximilien Brice/ CERN) What do the Higgs boson and a pizza have in common? Pierluigi Paolucci, INFN and CMS collaboration member, together with INFN president Fernando Ferroni found out the answer one day in Naples: the pizza in front of them looked exactly like a Higgs boson event display. A special recipe was then created in collaboration with the chef of the historic “Ettore” pizzeria in the St. Lucia area of Naples, and two pizzas were designed to resemble two Higgs boson decay channel event displays. The “Higgs Boson Pizza Day” was held on Monday, 4 July 2016, on the fourth anniversary of the announcement of the discovery of the Higgs boso...
International Nuclear Information System (INIS)
Jersak, J.
1986-01-01
This year has brought a sudden interest in lattice Higgs models. After five years of only modest activity we now have many new results obtained both by analytic and Monte Carlo methods. This talk is a review of the present state of lattice Higgs models with particular emphasis on the recent development
Energy Technology Data Exchange (ETDEWEB)
Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tsutomu [Kyoto Univ. (Japan). Hakubi Center; Kyoto Univ. (Japan). Dept. of Physics; Takahashi, Tomo [Saga Univ. (Japan). Dept. of Physics; Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics; Yokoyama, Jun' ichi [Tokyo Univ. (JP). Research Center for the Early Universe (RESCEU); Tokyo Univ., Chiba (JP). Inst. for the Physics and Mathematics of the Universe (IPMU)
2012-03-15
We study Higgs inflation in the context of generalized G-inflation, i.e., the most general single-field inflation model with second-order field equations. The four variants of Higgs inflation proposed so far in the literature can be accommodated at one time in our framework. We also propose yet another class of Higgs inflation, the running Einstein inflation model, that can naturally arise from the generalized G-inflation framework. As a result, five Higgs inflation models in all should be discussed on an equal footing. Concise formulas for primordial fluctuations in these generalized Higgs inflation models are provided, which will be helpful to determine which model is favored from the future experiments and observations such as the Large Hadron Collider and the Planck satellite.
Energy Technology Data Exchange (ETDEWEB)
Duerr, Michael; Grohsjean, Alexander; Kahlhoefer, Felix; Schmidt-Hoberg, Kai; Schwanenberger, Christian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Penning, Bjoern [Bristol Univ. (United Kingdom). H.H. Wills Physics Lab.
2017-05-15
We discuss a novel signature of dark matter production at the LHC resulting from the emission of an additional Higgs boson in the dark sector. The presence of such a dark Higgs boson is motivated simultaneously by the need to generate the masses of the particles in the dark sector and the possibility to relax constraints from the dark matter relic abundance by opening up a new annihilation channel. If the dark Higgs boson decays into Standard Model states via a small mixing with the Standard Model Higgs boson, one obtains characteristic large-radius jets in association with missing transverse momentum that can be used to efficiently discriminate signal from backgrounds. We present the sensitivities achievable in LHC searches for dark Higgs bosons with already collected data and demonstrate that such searches can probe large regions of parameter space that are inaccessible to conventional mono-jet or di-jet searches.
Strongly interacting Higgs bosons
International Nuclear Information System (INIS)
Appelquist, T.; Bernard, C.
1980-01-01
The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed
International Nuclear Information System (INIS)
Schlaffer, Matthias; Spannowsky, Michael; Wymant, Chris
2014-05-01
The inclusive Higgs production rate through gluon fusion has been measured to be in agreement with the Standard Model (SM). We show that even if the inclusive Higgs production rate is very SM-like, a precise determination of the boosted Higgs transverse momentum shape offers the opportunity to see effects of natural new physics. These measurements are generically motivated by effective field theory arguments and specifically in extensions of the SM with a natural weak scale, like composite Higgs models and natural supersymmetry. We show in detail how a measurement at high transverse momentum of H→2l+p T via H→ττ and H→WW * could be performed and demonstrate that it offers a compelling alternative to the t anti tH channel. We discuss the sensitivity to new physics in the most challenging scenario of an exactly SM-like inclusive Higgs cross-section.
International Nuclear Information System (INIS)
Duerr, Michael; Grohsjean, Alexander; Kahlhoefer, Felix; Schmidt-Hoberg, Kai; Schwanenberger, Christian; Penning, Bjoern
2017-05-01
We discuss a novel signature of dark matter production at the LHC resulting from the emission of an additional Higgs boson in the dark sector. The presence of such a dark Higgs boson is motivated simultaneously by the need to generate the masses of the particles in the dark sector and the possibility to relax constraints from the dark matter relic abundance by opening up a new annihilation channel. If the dark Higgs boson decays into Standard Model states via a small mixing with the Standard Model Higgs boson, one obtains characteristic large-radius jets in association with missing transverse momentum that can be used to efficiently discriminate signal from backgrounds. We present the sensitivities achievable in LHC searches for dark Higgs bosons with already collected data and demonstrate that such searches can probe large regions of parameter space that are inaccessible to conventional mono-jet or di-jet searches.
Espana entra en un programa de fisica rechazado por los cientificos
Rivera, A
2002-01-01
"El Ministerio de Ciencia y Tecnologia (MCyT) anuncio ayer la aprobacion de un acuerdo de colaboracion con el Laboratorio Europeo de Fisica de Particulas (CERN), junto a Ginebra, para un programa de investigacion de neutrinos (CNGS)" (1 page).
Le avventure di Mr. Tompkins viaggio "scientificamente fantastico" nel mondo della fisica
Gamow, George
1993-01-01
Questo classico della divulgazione scientifica offre al lettore una grande quantità di informazioni e una spiegazione dei concetti fondamentali della fisica moderna: la struttura dell'atomo, la relatività e la teoria quantistica, la fusione e la fissione. La prefazione di Roger Penrose presenta Mr. Tompkins ad una nuova generazione di lettori e rivisita le sue avventure alla luce degli attuali sviluppi della fisica moderna.
Energy Technology Data Exchange (ETDEWEB)
Alonso Diaz, A.
2007-12-28
This note presents a Higgs boson search analysis in the CMS detector of the LHC accelerator (CERN, Geneva, Switzerland) in the H{yields} ZZ{sup (*)}{yields}4{mu} channel, using a multivariate method. This analysis, based in a Higgs boson mass dependent likelihood, constructed from discriminant variables, provides a significant improvement of the Higgs boson discovery potential in a wide mass range with respect to the official analysis published by CMS, based in orthogonal cuts independent of the Higgs boson mass. (Author) 8 refs.
Maccioni, Elena Lucia
Este Trabajo Fin de Master tiene como objeto, el estudio previo de la educacion de la ciencia en la actualidad y mas destacable, del diseno de las unidades didacticas segun las metodologias mas frecuentes aplicadas por los diferentes sistemas educativos en el area de las Ciencias teniendo en cuenta la importancia y el efecto de la psicologia del alumnado y todo ello como no puede ser de otro modo bajo el corse de la Legislacion aplicable, Estatal, Autonomica y europea. Con estos antecedentes, se extrae cuales son las preguntas que deben contestarse en la elaboracion de una unidad didactica de calidad en el contexto, generacional (edad y sexo), del Proyecto Educativo de Centro, y de la Programacion del Departamento, discutiendo y justificando cada uno de los apartados en que estructuradamente dividiremos dicha Unidad, con un formato manejable, util, y dinamico en el tiempo que sea un verdadero instrumento educativo de aula. Teniendo en cuenta estas premisas, se procede a hacer una recopilacion de una misma unidad didactica publicada por diferentes editoriales, elegidas no al azar, sino en funcion de su penetracion editorial en nuestros centros de ESO, siendo las elegidas (SM y Oxford). Las diferentes unidades seleccionadas son analizadas de forma critica, atendiendo a los criterios generales de calidad bajo parametros cientificos y normativos, concluyendo con la aportacion final que es la redaccion de unas pautas cientifico-pedagogicas, para redactar unidades didacticas de calidad en el area de la Ciencias, en concreto en la Asignatura de Fisica y Quimica de 3º de ESO.
Owen, Mark
2009-09-01
The Higgs boson is essential to achieve electroweak symmetry breaking in the Standard Model. Results on searches for the Higgs boson using data collected in pbar p collisions at √ s = 1.96 {TeV} with the DØ detector at the Fermilab Teva-tron collider are presented. The data, corresponding to integrated luminosities between 1 fb-1 and 2 fb-1 show no excess above the expected backgrounds and as such upper limits on the production cross section of Higgs bosons are set at the 95% confidence level.
Energy Technology Data Exchange (ETDEWEB)
Navarro, E.; Garcia, P.; Hernandez, J. M.
2013-02-01
This work presents the search for a Higgs boson-like particle, responsible for the spontaneous breaking of the electroweak symmetry of the Standard Model of particle physics. Proton collision data collected by the CMS experiment of LHC during the year 2011 have been used. The work is focused on the final state with two leptons and two bottom quarks coming from a pair of Z bosons. The analysis of the data tries to isolate a signal from the contribution of known processes, using the characteristic kinematic of the signal. The results allowed to establish limits to the production cross section of a Higgs boson with masses between 200 and 600 GeV. (Author) 22 refs.
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Oleg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lee, Hyun Min [European Organization for Nuclear Research (CERN), Geneva (Switzerland)
2011-05-15
The Higgs sector of the Standard Model offers a unique opportunity to probe the hidden sector. The Higgs squared operator is the only dimension two operator which is Lorentz and gauge invariant. It can therefore couple both to scalar curvature and the hidden sector at the dim-4 level. We consider the possibility that a combination of the Higgs and a singlet from the hidden sector plays the role of inflaton, due to their large couplings to gravity. This implies that the quartic couplings satisfy certain constraints which leads to distinct low energy phenomenology, including Higgs signals at the LHC. We also address the unitarity issues and show that our analysis survives the unitarization procedure. (orig.)
Partially composite Higgs models
DEFF Research Database (Denmark)
Alanne, Tommi; Buarque Franzosi, Diogo; Frandsen, Mads T.
2018-01-01
We study the phenomenology of partially composite-Higgs models where electroweak symmetry breaking is dynamically induced, and the Higgs is a mixture of a composite and an elementary state. The models considered have explicit realizations in terms of gauge-Yukawa theories with new strongly...... interacting fermions coupled to elementary scalars and allow for a very SM-like Higgs state. We study constraints on their parameter spaces from vacuum stability and perturbativity as well as from LHC results and find that requiring vacuum stability up to the compositeness scale already imposes relevant...... constraints. A small part of parameter space around the classically conformal limit is stable up to the Planck scale. This is however already strongly disfavored by LHC results. in different limits, the models realize both (partially) composite-Higgs and (bosonic) technicolor models and a dynamical extension...
Parker, Andy
1996-01-01
The Higgs boson is the most mysterious of all the fundamental particles. It accounts for how other particles acquired mass just after the beginning of the Universe. LEP-2 and the LHC at CERN will hunt it down between them
Lebedev, Oleg
2011-01-01
The Higgs sector of the Standard Model offers a unique opportunity to probe the hidden sector. The Higgs squared operator is the only dimension two operator which is Lorentz and gauge invariant. It can therefore couple both to scalar curvature and the hidden sector at the dim--4 level. We consider the possibility that a combination of the Higgs and a singlet from the hidden sector plays the role of inflaton, due to their large couplings to gravity. This implies that the quartic couplings satisfy certain constraints which leads to distinct low energy phenomenology, including Higgs signals at the LHC. We also address the unitarity issues and show that our analysis survives the unitarization procedure.
Dezso, Horvath
2017-01-01
A részecskefizika általánosan elfogadott és az elmúlt 40 év alatt sokszorosan igazolt elmélete, a standard modell valamennyi alkatrészét sikerült megfigyelni és tanulmányozni a Higgs-bozon kivételével. A CERN nagy hadronütköztetője (LHC), a világ legnagyobb részecskegyorsítója is elsősorban a Higgs-részecske kimutatására épült. 2012 közepére az LHC két óriási mérőberendezése, a sok ezer fizikus részvételével épült CMS és ATLAS megfigyelt egy - a Higgs-bozon elméletileg megjósolt tulajdonságaival rendelkező - új részecskét. A könyv áttekinti a standard modell elméletét és a Higgs-részecske feltételezett tulajdonságait, majd összefoglalja az LHC Higgs-keresési eredményeit és a hozzájuk vezető utat. Függelékben ismerteti a könyvben előforduló fizikusok életrajzát és bizonyos fizikai fogalmak részletesebb leírását. A 2013-as fizikai Nobel-díjat Peter Higgs és François Englert kapták megosztva a Higgs-mechanizmus és a Higgs-bozon elmé...
Hawkes, N
1999-01-01
A conference in the US has suggested that the mass of the Higgs boson may not be as large as previously thought. It may be within the reach of the Tevatron at Fermilab if it operates for longer than the planned two years. If so, the LHC designed specifically to find the Higgs boson may be beaten to the discovery before it is even built (1/2 page).
AUTHOR|(CDS)2073690
2016-01-01
The Compact Linear Collider (CLIC) is an attractive option for a future multi-TeV linear electron-positron collider, offering the potential for a rich precision physics programme, combined with sensitivity to a wide range of new phenomena. The physics reach of CLIC has been studied in the context of three distinct centre-of-mass energies, √s = 350 GeV, 1.4 TeV and 3.0 TeV. This staged scenario provides an excellent environment for precise studies of the properties of the 126 GeV Higgs boson. Operation at √s = 350 GeV allows, on the one hand, for a determination of the couplings and width of the Higgs boson in a model-independent manner through the study of the Higgsstrahlung process, and on the other hand, for a study of Higgs bosons produced in W+W− fusion for the most common Higgs decay modes. Operation at higher centre-of-mass energies, √s = 1.4 TeV and 3 TeV, provides high statistics W+W− fusion samples allowing for high precision measurements of many Higgs couplings and a study of rare Higgs de...
SM Higgs decay branching ratios and total Higgs width
Daniel Denegri
2001-01-01
Upper: Higgs decay ratios as a function of Higgs mass. The largest branching ratio is not necessarily the most usefull one. The most usefull ones are gamma gamma bbar ZZ and WW as in those modes latter signal to background ratios can be achieved. Lower: Total Higgs decay width versus Higgs mass. At low masses the natural width is extremely small, thus observability depends on instrumental resolution primarily.
Working Group Report: Higgs Boson
Energy Technology Data Exchange (ETDEWEB)
Dawson, Sally; Gritsan, Andrei; Logan, Heather; Qian, Jianming; Tully, Chris; Van Kooten, Rick [et al.
2013-10-30
This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $CP$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).
Higgs boson transverse momentum distribution
CERN. Geneva
2018-01-01
I will review the recent progress in understanding Higgs boson transverse momentum distribution focusing on effects that go beyond the point-like approximation for the Higgs-glue interaction vertex.
Tools for charged Higgs bosons
International Nuclear Information System (INIS)
Staal, Oscar
2010-12-01
We review the status of publicly available software tools applicable to charged Higgs physics. A selection of codes are highlighted in more detail, focusing on new developments that have taken place since the previous charged Higgs workshop in 2008. We conclude that phenomenologists now have the tools ready to face the LHC data. A new web page collecting charged Higgs resources is presented. (orig.)
Finite-Temperature Higgs Potentials
International Nuclear Information System (INIS)
Dolgopolov, M.V.; Gurskaya, A.V.; Rykova, E.N.
2016-01-01
In the present article we consider the short description of the “Finite-Temperature Higgs Potentials” program for calculating loop integrals at vanishing external momenta and applications for extended Higgs potentials reconstructions. Here we collect the analytic forms of the relevant loop integrals for our work in reconstruction of the effective Higgs potential parameters in extended models (MSSM, NMSSM and etc.)
Colas, Paul
2003-01-01
The Higgs boson was theoretically created about 40 years ago by a Scott Peter Higgs who wanted to explain why some particles get a mass. Since then the Higgs boson has taken consistency and has become an important point of the standard model theory. Its experimental discovery would be a milestone of modern physics. The search for the Higgs boson is an international challenge that takes place around 2 huge machines: the Tevatron near Chicago and the LHC (large hadron collider) that is being built in CERN. The Tevatron is in fact the upgrading of an old particle accelerator, it is a proton collider and its narrow range of energy is compensated by a low background noise. On the other hand the LHC will begin operating only in 2007 and its full power will be reached a few years later, the energy available to create particles will be then 7 times higher than for the Tevatron. Both machines have chance of succeeding by being the first to detect the Higgs boson. Time plays in favor of the Tevatron but in any case if ...
CERN. Geneva
2011-01-01
The excellent performances of the LHC in the 2011 run are setting the grounds for the final chase of the Higgs boson. The CMS experiment is recording high quality data that are being thoroughly scrutinized. Several decay channels are investigated to probe the entire possible Higgs mass spectrum, from 110 to 600 GeV/c^2. The study of the first 1.5/fb of collected data places already tight limits and excludes large fractions of the Higgs mass range, leaving however still open the search in the theoretically favored low mass region. In this seminar we will report on the diverse CMS analyses that yield to such results describing the experimental challenges that each had to meet.
Brunet, S
2014-01-01
ATLAS Higgs poster targeted to general public, explaining the Brout-Englert-Higgs mechanism and why it is important. It also explains the role of the Higgs Boson, how we look for it, the journey of the discovery and what comes after the discovery. Also available in French (http://cds.cern.ch/record/1697501). Don’t hesitate to use it in your institute’s corridors and in your outreach events! The poster is in A0 format. You can click on the image to download the high-quality .pdf version and print it at your favorite printshop. For any questions or comments you can contact atlas-outreach-coordination@cern.ch.
CERN. Geneva
2015-01-01
After reviewing the nice properties of Higgs inflation and some of its problems, I will discuss a simple unitarization of the scenario that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Inflationary dynamics is not dominated by the Higgs field, but 'Higgs inflation' arises as an approximate 'mirage' picture of the true dynamics. I will speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.
Energy Technology Data Exchange (ETDEWEB)
Anon.
1986-03-15
The unified theory of electromagnetism and the weak nuclear force, crowned with the discovery at CERN in 1983 of the W and Z bosons which carry the weak nuclear force, is one of the great triumphs of modern physics. But the picture is not yet complete. An essential but still elusive ingredient is the so-called 'Higgs boson' (after Edinburgh theorist Peter Higgs), responsible for the vital symmetry breaking in the theory. This gives the carriers of the weak force mass, while the photon, the carrier of electromagnetism, is massless.
Trent'anni che sconvolsero la fisica la storia della teoria dei quanti
Gamow, George
1993-01-01
Gli anni dal 1900 al 1930 hanno portato un profondo mutamento nella visione che l'uomo aveva dell'universo: tra la prima idea di Max Planck dei quanti di luce nel 1900, e la previsione dell'esistenza delle antiparticelle formulata da P. A. M. Dirac nel 1929, corre un periodo di emozionanti progressi nel campo della fisica teorica.
Hein, Till
2005-01-01
CERN's physicists are worried by a great question: does the universe remain stable? Why does the world exist? To answer, they look for the infinitely small and are trying to find the "key": the hypothetical Higgs-boson (4½ pages)
Disentangling a dynamical Higgs
International Nuclear Information System (INIS)
Brivio, I.; Corbett, T.; Éboli, O.J.P.; Gavela, M.B.; Gonzalez-Fraile, J.; Gonzalez-Garcia, M.C.; Merlo, L.; Rigolin, S.
2014-01-01
The pattern of deviations from Standard Model predictions and couplings is different for theories of new physics based on a non-linear realization of the SU(2) L ×U(1) Y gauge symmetry breaking and those assuming a linear realization. We clarify this issue in a model-independent way via its effective Lagrangian formulation in the presence of a light Higgs particle, up to first order in the expansions: dimension-six operators for the linear expansion and four derivatives for the non-linear one. Complete sets of gauge and gauge-Higgs operators are considered, implementing the renormalization procedure and deriving the Feynman rules for the non-linear expansion. We establish the theoretical relation and the differences in physics impact between the two expansions. Promising discriminating signals include the decorrelation in the non-linear case of signals correlated in the linear one: some pure gauge versus gauge-Higgs couplings and also between couplings with the same number of Higgs legs. Furthermore, anomalous signals expected at first order in the non-linear realization may appear only at higher orders of the linear one, and vice versa. We analyze in detail the impact of both type of discriminating signals on LHC physics
Bellazzini, Brando; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John
2016-01-01
The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in AdS space. For both of these models we consider the processes $gg\\to ZZ$ and $gg\\to hh$, which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.
Indian Academy of Sciences (India)
The large hadron collider (LHC) and its detectors, ATLAS and CMS, are being built to study TeV scale physics, and to fully understand the electroweak symmetry breaking mechanism. The Monte-Carlo simulation results for the standard model and minimal super symmetric standard model Higgs boson searches and ...
Bellazzini, Brando; Csáki, Csaba; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John
2016-10-01
The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However, light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper, we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in anti-de Sitter space. For both of these models, we consider the processes g g →Z Z and g g →h h , which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.
Disentangling a dynamical Higgs
Energy Technology Data Exchange (ETDEWEB)
Brivio, I. [Departamento de Física Teórica and Instituto de Física Teórica, IFT-UAM/CSIC,Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid (Spain); Corbett, T. [C.N. Yang Institute for Theoretical Physics and Department of Physics and Astronomy,SUNY at Stony Brook, Stony Brook, NY 11794-3840 (United States); Éboli, O.J.P. [Instituto de Física, Universidade de São Paulo,C.P. 66318, 05315-970, São Paulo SP (Brazil); Gavela, M.B. [Departamento de Física Teórica and Instituto de Física Teórica, IFT-UAM/CSIC,Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid (Spain); Gonzalez-Fraile, J. [Departament d’Estructura i Constituents de la Matèria and ICC-UB, Universitat de Barcelona,647 Diagonal, E-08028 Barcelona (Spain); Gonzalez-Garcia, M.C. [Institució Catalana de Recerca i Estudis Avançats (ICREA),Passeig Lluís Companys, 23, E-08010 Barcelona (Spain); Departament d’Estructura i Constituents de la Matèria and ICC-UB, Universitat de Barcelona,647 Diagonal, E-08028 Barcelona (Spain); C.N. Yang Institute for Theoretical Physics and Department of Physics and Astronomy,SUNY at Stony Brook, Stony Brook, NY 11794-3840 (United States); Merlo, L. [Departamento de Física Teórica and Instituto de Física Teórica, IFT-UAM/CSIC,Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid (Spain); Rigolin, S. [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padua (Italy)
2014-03-05
The pattern of deviations from Standard Model predictions and couplings is different for theories of new physics based on a non-linear realization of the SU(2){sub L}×U(1){sub Y} gauge symmetry breaking and those assuming a linear realization. We clarify this issue in a model-independent way via its effective Lagrangian formulation in the presence of a light Higgs particle, up to first order in the expansions: dimension-six operators for the linear expansion and four derivatives for the non-linear one. Complete sets of gauge and gauge-Higgs operators are considered, implementing the renormalization procedure and deriving the Feynman rules for the non-linear expansion. We establish the theoretical relation and the differences in physics impact between the two expansions. Promising discriminating signals include the decorrelation in the non-linear case of signals correlated in the linear one: some pure gauge versus gauge-Higgs couplings and also between couplings with the same number of Higgs legs. Furthermore, anomalous signals expected at first order in the non-linear realization may appear only at higher orders of the linear one, and vice versa. We analyze in detail the impact of both type of discriminating signals on LHC physics.
Energy Technology Data Exchange (ETDEWEB)
Barbieri, Riccardo [Institute of Theoretical Studies, ETH Zurich,CH-8092 Zurich (Switzerland); Scuola Normale Superiore,Piazza dei Cavalieri 7, 56126 Pisa (Italy); Hall, Lawrence J.; Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States)
2016-11-29
In a Mirror Twin World with a maximally symmetric Higgs sector the little hierarchy of the Standard Model can be significantly mitigated, perhaps displacing the cutoff scale above the LHC reach. We show that consistency with observations requires that the Z{sub 2} parity exchanging the Standard Model with its mirror be broken in the Yukawa couplings. A minimal such effective field theory, with this sole Z{sub 2} breaking, can generate the Z{sub 2} breaking in the Higgs sector necessary for the Twin Higgs mechanism. The theory has constrained and correlated signals in Higgs decays, direct Dark Matter Detection and Dark Radiation, all within reach of foreseen experiments, over a region of parameter space where the fine-tuning for the electroweak scale is 10-50%. For dark matter, both mirror neutrons and a variety of self-interacting mirror atoms are considered. Neutrino mass signals and the effects of a possible additional Z{sub 2} breaking from the vacuum expectation values of B−L breaking fields are also discussed.
Bruno Touschek e l'arte della fisica
Agapito, Enrico
2007-01-01
Bruno Touschek, nato a Vienna nel 1921 e morto a Igls, in Austria, nel 1978, fu il fisico che nel 1960 progettò e portò a compimento, la costruzione di AdA, il primo Anello di Accumulazione di materia e antimateria (elettroni e positroni), presso i Laboratori del CNEN di Frascati.
Electroweak Higgs production with HiggsPO at NLO QCD
International Nuclear Information System (INIS)
Greljo, Admir; Isidori, Gino; Zhang, Hantian; Lindert, Jonas M.; Marzocca, David
2017-01-01
We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus important to be considered in realistic experimental analyses, the QCD higher-order corrections largely factorize. As an additional finding, based on the NLO results, we advocate to consider 2D distributions of the two-jet azimuthal-angle difference and the leading jet p T for new physics searches in VBF Higgs production. The HiggsPO UFO model is publicly available. (orig.)
Electroweak Higgs production with HiggsPO at NLO QCD
Greljo, Admir; Isidori, Gino; Lindert, Jonas M.; Marzocca, David; Zhang, Hantian
2017-12-01
We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus important to be considered in realistic experimental analyses, the QCD higher-order corrections largely factorize. As an additional finding, based on the NLO results, we advocate to consider 2D distributions of the two-jet azimuthal-angle difference and the leading jet p_T for new physics searches in VBF Higgs production. The HiggsPO UFO model is publicly available.
Electroweak Higgs production with HiggsPO at NLO QCD
Energy Technology Data Exchange (ETDEWEB)
Greljo, Admir [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Johannes Gutenberg-Universitaet Mainz, PRISMA Cluster of Excellence and Mainz Institute for Theoretical Physics, Mainz (Germany); University of Sarajevo, Faculty of Science, Sarajevo (Bosnia and Herzegovina); Isidori, Gino; Zhang, Hantian [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Lindert, Jonas M. [Durham University, Department of Physics, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Marzocca, David [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); INFN, Sezione di Trieste(Italy); SISSA, Trieste (Italy)
2017-12-15
We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus important to be considered in realistic experimental analyses, the QCD higher-order corrections largely factorize. As an additional finding, based on the NLO results, we advocate to consider 2D distributions of the two-jet azimuthal-angle difference and the leading jet p{sub T} for new physics searches in VBF Higgs production. The HiggsPO UFO model is publicly available. (orig.)
International Nuclear Information System (INIS)
Hueffel, H.
1980-01-01
In the framework of the minimal SU(5) model of Georgi and Glashow the explicit couplings between the various mass eigenstate Higgs bosons and the gauge fields as well as the Higgs boson self couplings are presented. As an application bounds for the parameters of the Higgs potential and for the Higgs boson masses are derived by applying partial wave unitarity to the tree graphs of Higgs-Higgs scattering. (Auth.)
Le forze della natura il nuovo orizzonte della fisica
Davies, Paul C W
1990-01-01
Vero "cavallo di razza" della divulgazione scientifica, Paul Davies è uno dei rari fisici che sanno farsi seguire dal lettore comune anche quando affrontano argomenti difficili. Ne è una prova il presente volume, una delle migliori illustrazioni disponibili del microcosmo atomico e dell'incredibile fauna che lo abita : non solo la familiare triade protone-elettrone-neutrone, ma le ben più intriganti realtà che vanno sotto il nome di "colore", "incanto", stranezza".
The Higgs portal above threshold
Energy Technology Data Exchange (ETDEWEB)
Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Lou, Hou Keong [Department of Physics, Princeton University,Princeton, NJ 08540 (United States); McCullough, Matthew [Theory Division, CERN,1211 Geneva 23 (Switzerland); Thalapillil, Arun [Department of Physics and Astronomy, Rutgers University,Piscataway, NJ 08854 (United States)
2016-02-18
The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √s=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.
Energy Technology Data Exchange (ETDEWEB)
Barbón, J.L.F.; Casas, J.A. [IFT-UAM/CSIC, Universidad Autónoma de Madrid,C/Nicolás Cabrera 13, 28049 Madrid (Spain); Elias-Miró, J. [Departament de Física/IFAE, Universitat Autònoma de Barcelona,Edifici Cn, 08193 Bellaterra, Barcelona (Spain); Espinosa, J.R. [ICREA/IFAE, Universitat Autònoma de Barcelona,Edifici Cn, 08193 Bellaterra, Barcelona (Spain)
2015-09-04
We discuss a simple unitarization of Higgs inflation that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Despite not being dominated by the Higgs field, inflationary dynamics simulates the ‘Higgs inflation’ one would get by blind extrapolation of the low-energy effective Lagrangian, at least qualitatively. Hence, Higgs inflation arises as an approximate ‘mirage’ picture of the true dynamics. We further speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.
Heavy Higgs searches. Flavour matters
International Nuclear Information System (INIS)
Gori, Stefania; Paul, Ayan
2017-10-01
We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.
The Higgs portal above threshold
International Nuclear Information System (INIS)
Craig, Nathaniel; Lou, Hou Keong; McCullough, Matthew; Thalapillil, Arun
2016-01-01
The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √s=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.
Heavy Higgs searches. Flavour matters
Energy Technology Data Exchange (ETDEWEB)
Gori, Stefania [Cincinnati Univ., OH (United States). Dept. of Physics; Grojean, Christophe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Juste, Aurelio [Institut de Fisica d' Altes Energies (IFAE), Barcelona (Spain); Institucio Catalanade Recerca i Estudis Avancats (ICREA), Barcelona (Spain); Paul, Ayan [INFN, Sezione di Roma (Italy)
2017-10-15
We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.
International Nuclear Information System (INIS)
Barbón, J.L.F.; Casas, J.A.; Elias-Miró, J.; Espinosa, J.R.
2015-01-01
We discuss a simple unitarization of Higgs inflation that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Despite not being dominated by the Higgs field, inflationary dynamics simulates the ‘Higgs inflation’ one would get by blind extrapolation of the low-energy effective Lagrangian, at least qualitatively. Hence, Higgs inflation arises as an approximate ‘mirage’ picture of the true dynamics. We further speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.
Maximally Symmetric Composite Higgs Models.
Csáki, Csaba; Ma, Teng; Shu, Jing
2017-09-29
Maximal symmetry is a novel tool for composite pseudo Goldstone boson Higgs models: it is a remnant of an enhanced global symmetry of the composite fermion sector involving a twisting with the Higgs field. Maximal symmetry has far-reaching consequences: it ensures that the Higgs potential is finite and fully calculable, and also minimizes the tuning. We present a detailed analysis of the maximally symmetric SO(5)/SO(4) model and comment on its observational consequences.
Light Higgs from pole attractor
International Nuclear Information System (INIS)
Matsedonskyi, Oleksii; Montull, Marc
2017-09-01
We propose a new way of explaining the observed Higgs mass, within the cosmological relaxation framework. The key feature distinguishing it from other scanning scenarios is that the scanning field has a non-canonical kinetic term, whose role is to terminate the scan around the desired Higgs mass value. We propose a concrete realisation of this idea with two new singlet fields, one that scans the Higgs mass, and another that limits the time window in which the scan is possible. Within the provided time period, the scanning field does not significantly evolve after the Higgs field gets close to the Standard Model value, due to particle production friction.
International Nuclear Information System (INIS)
Ekspong, G.
1981-11-01
Among possible production reactions for neutral Higgs bosons it is known that e + e - →Z 0 +H 0 offers advantages of relatively high production cross section and low background from other reactions. With Z 0 decaying to two electrons, which are measured, the existence of a Higgs candidate will be seen as a peak in the missing mass spectrum. It is shown that a sufficiently good mass resolution is obtainable to make a search for Higgs feasible at LEP. In its first phase, the energy of LEP limits the search to Higgs bosons of mass around 10 GeV. (Auth.)
Higgs mass bounds from a chirally invariant lattice Higgs-Yukawa model with overlap fermions
International Nuclear Information System (INIS)
Gerhold, Philipp; Kallarackal, Jim
2008-10-01
We study the parameter dependence of the Higgs mass in a chirally invariant lattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure as in the Higgs sector of the electroweak Standard Model. Eventually, the aim is to establish upper and lower Higgs mass bounds. Here we present our preliminary results on the lower Higgs mass bound at several selected values for the cutoff and give a brief outlook towards the upper Higgs mass bound. (orig.)
The limit of the Yang-Mills-Higgs flow on Higgs bundles
Li, Jiayu; Zhang, Xi
2014-01-01
In this paper, we consider the gradient flow of the Yang-Mills-Higgs functional for Higgs pairs on a Hermitian vector bundle $(E, H_{0})$ over a compact K\\"ahler manifold $(M, \\omega )$. We study the asymptotic behavior of the Yang-Mills-Higgs flow for Higgs pairs at infinity, and show that the limiting Higgs sheaf is isomorphic to the double dual of the graded Higgs sheaves associated to the Harder-Narasimhan-Seshadri filtration of the initial Higgs bundle.
Integrating over Higgs branches
International Nuclear Information System (INIS)
Moore, G.; Shatashvili, S.
2000-01-01
We develop some useful techniques for integrating over Higgs branches in supersymmetric theories with 4 and 8 supercharges. In particular, we define a regularized volume for hyperkaehler quotients. We evaluate this volume for certain ALE and ALF spaces in terms of the hyperkaehler periods. We also reduce these volumes for a large class of hyperkaehler quotients to simpler integrals. These quotients include complex coadjoint orbits, instanton moduli spaces on R 4 and ALE manifolds, Hitchin spaces, and moduli spaces of (parabolic) Higgs bundles on Riemann surfaces. In the case of Hitchin spaces the evaluation of the volume reduces to a summation over solutions of Bethe ansatz equations for the non-linear Schroedinger system. We discuss some applications of our results. (orig.)
2001-01-01
This track is an example of real data collected from the DELPHI detector on the Large Electron-Positron (LEP) collider at CERN, which ran between 1989 and 2000. Its topology is compatible with what is expected from the associated production of a Z boson and Higgs boson of mass 113 GeV that each decay into two jets. A different pairing of the jets could lead to an interpretation compatible with the production of two Z bosons.
Indian Academy of Sciences (India)
2012-10-06
Oct 6, 2012 ... confidence level (CL) established at LEP2 [4]. ... particle is not self-consistent at high energies as it leads to ... matter and thus impact their density in the Universe today. ... s = 7 TeV LHC, lead to a K-factor KNLO ∼ 1.8 in the low Higgs mass ...... See Michael Spira, http://people.web.psi.ch/spira/proglist.html.
Energy Technology Data Exchange (ETDEWEB)
Dobrescu, Bogdan A.; Fox, Patrick J.; Kearney, John [Fermilab, Theoretical Physics Department, Batavia, IL (United States)
2017-10-15
We study models that produce a Higgs boson plus photon (h{sup 0}γ) resonance at the LHC. When the resonance is a Z{sup '} boson, decays to h{sup 0}γ occur at one loop. If the Z{sup '} boson couples at tree level to quarks, then the h{sup 0}γ branching fraction is typically of order 10{sup -5} or smaller. Nevertheless, there are models that would allow the observation of Z{sup '} → h{sup 0}γ at √(s) = 13 TeV with a cross section times branching fraction larger than 1 fb for a Z{sup '} mass in the 200-450 GeV range, and larger than 0.1 fb for a mass up to 800 GeV. The one-loop decay of the Z{sup '} into lepton pairs competes with h{sup 0}γ, even if the Z{sup '} couplings to leptons vanish at tree level. We also present a model in which a Z{sup '} boson decays into a Higgs boson and a pair of collimated photons, mimicking an h{sup 0}γ resonance. In this model, the h{sup 0}γ resonance search would be the discovery mode for a Z{sup '} as heavy as 2 TeV. When the resonance is a scalar, although decay to h{sup 0}γ is forbidden by angular momentum conservation, the h{sup 0} plus collimated photons channel is allowed. We comment on prospects of observing an h{sup 0}γ resonance through different Higgs decays, on constraints from related searches, and on models where h{sup 0} is replaced by a nonstandard Higgs boson. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Buchmueller, O. [Imperial College, London (United Kingdom). High Energy Physics Group; Cavanaugh, R. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Illinois Univ, Chicago, IL (United States). Physics Dept.; Roeck, A. de [CERN, Geneva (Switzerland); Antwerp Univ., Wilrijk (BE)] (and others)
2011-12-15
Global frequentist fits to the CMSSM and NUHM1 using the MasterCode framework predicted M{sub h}{approx_equal}119 GeV in fits incorporating the (g-2){mu} constraint and {approx_equal}126 GeV without it. Recent results by ATLAS and CMS could be compatible with a Standard Model-like Higgs boson around M{sub h}{approx_equal}125 GeV. We use the previous MasterCode analysis to calculate the likelihood for a measurement of any nominal Higgs mass within the range of 115 to 130 GeV. Assuming a Higgs mass measurement at M{sub h}{approx_equal}125 GeV, we display updated global likelihood contours in the (m{sub 0},m{sub 1/2}) and other parameter planes of the CMSSM and NUHM1, and present updated likelihood functions for m{sub g}, m{sub q{sub R}}, BR(B{sub s} {yields} {mu}{sup +}{mu}{sup -}) and the spin-independent dark matter cross section {sigma}{sup SI}{sub p}. The implications of dropping (g-2){sub {mu}} from the fits are also discussed. We furthermore comment on a hypothetical measurement of M{sub h}{approx_equal}119 GeV. (orig.)
Vector Higgs-portal dark matter and the invisible Higgs
International Nuclear Information System (INIS)
Lebedev, Oleg; Lee, Hyun Min; Mambrini, Yann
2011-11-01
The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z 2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stueckelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson. (orig.)
Vector Higgs-portal dark matter and the invisible Higgs
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Oleg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lee, Hyun Min [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Mambrini, Yann [Paris-Sud Univ., 91 - Orsay (France). Lab. de Physique Theorique
2011-11-15
The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z{sub 2} parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stueckelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson. (orig.)
Vector Higgs portal dark matter and the invisible Higgs
International Nuclear Information System (INIS)
Lebedev, Oleg; Lee, Hyun Min; Mambrini, Yann
2012-01-01
The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z 2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stückelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson.
Roberts, Alex
2016-08-01
Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and outcomes of particular experiments, according to a single probability formula. This provides complete unification of the eternally inflating multiverse and many worlds in quantum mechanics. We elucidate how cosmological parameters can be calculated in this framework, and study the probability distribution for the value of the cosmological constant. We consider both positive and negative values, and find that the observed value is consistent with the calculated distribution at an order of magnitude level. In particular, in contrast to the case of earlier measure proposals, our framework prefers a positive cosmological constant over a negative one. These results depend only moderately on how we model galaxy formation and life evolution therein. We explore supersymmetric theories in which the Higgs mass is boosted by the non-decoupling D-terms of an extended U(1) X gauge symmetry, defined here to be a general linear combination of hypercharge, baryon number, and lepton number. Crucially, the gauge coupling, gX, is bounded from below to accommodate the Higgs mass, while the quarks and leptons are required by gauge invariance to carry non-zero charge under U(1)X. This induces an irreducible rate, sigmaBR, for pp → X → ll relevant to existing and future resonance searches, and gives rise to higher dimension operators that are stringently constrained by precision electroweak measurements. Combined, these bounds define a maximally allowed region in the space of observables, (sigmaBR, mX), outside of which is excluded by naturalness and experimental limits. If natural supersymmetry utilizes non-decoupling D-terms, then the associated X boson can only be observed within this window, providing a model independent 'litmus test' for this broad
Learning from Higgs physics at future Higgs factories
Energy Technology Data Exchange (ETDEWEB)
Gu, Jiayin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chinese Academy of Sciences, Beijing (China). Center for Future High Energy Physics; Li, Honglei [Jinan Univ., Shandong (China). School of Physics and Technology; Arizona Univ., Tucson, AZ (United States). Dept. of Physics; Liu, Zhen [Fermi National Accelerator Laboratory, Batavia, IL (United States). Theoretical Physics Dept.; Su, Shufang [Arizona Univ., Tucson, AZ (United States). Dept. of Physics; Su, Wei [Arizona Univ., Tucson, AZ (United States). Dept. of Physics; Chinese Academy of Sciences, Beijing (China). Inst. of Theoretical Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physics
2017-09-15
Future Higgs factories can reach impressive precision on Higgs property measurements. In this paper, instead of conventional focus of Higgs precision in certain interaction bases, we explored its sensitivity to new physics models at the electron-positron colliders. In particular, we studied two categories of new physics models, Standard Model (SM) with a real scalar singlet extension, and Two Higgs Double Model (2HDM) as examples of weakly-interacting models, Minimal Composite Higgs Model (MCHM) and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We performed a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter space. In the SM with a singlet extension, we obtained the limits on the singlet-doublet mixing angle sinθ, as well as the more general Wilson coefficients of the induced higher dimensional operators. In the 2HDM, we analyzed tree level effects in tanβ vs. cos(β-α) plane, as well as the one-loop contributions from the heavy Higgs bosons in the alignment limit to obtain the constraints on heavy Higgs masses for different types of 2HDM. In strong dynamics models, we obtained lower limits on the strong dynamics scale. In addition, once deviations of Higgs couplings are observed, they can be used to distinguish different models. We also compared the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).
Learning from Higgs physics at future Higgs factories
International Nuclear Information System (INIS)
Gu, Jiayin; Chinese Academy of Sciences, Beijing; Li, Honglei; Arizona Univ., Tucson, AZ; Liu, Zhen; Su, Shufang; Su, Wei; Chinese Academy of Sciences, Beijing; Univ. of Chinese Academy of Sciences, Beijing
2017-09-01
Future Higgs factories can reach impressive precision on Higgs property measurements. In this paper, instead of conventional focus of Higgs precision in certain interaction bases, we explored its sensitivity to new physics models at the electron-positron colliders. In particular, we studied two categories of new physics models, Standard Model (SM) with a real scalar singlet extension, and Two Higgs Double Model (2HDM) as examples of weakly-interacting models, Minimal Composite Higgs Model (MCHM) and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We performed a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter space. In the SM with a singlet extension, we obtained the limits on the singlet-doublet mixing angle sinθ, as well as the more general Wilson coefficients of the induced higher dimensional operators. In the 2HDM, we analyzed tree level effects in tanβ vs. cos(β-α) plane, as well as the one-loop contributions from the heavy Higgs bosons in the alignment limit to obtain the constraints on heavy Higgs masses for different types of 2HDM. In strong dynamics models, we obtained lower limits on the strong dynamics scale. In addition, once deviations of Higgs couplings are observed, they can be used to distinguish different models. We also compared the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).
Fisica e oltre incontri con i protagonisti (1920-1965)
Heisenberg, Werner
1984-01-01
In quest'opera, a un tempo rievocazione storica e autobiografia scientifica, Heisenberg intreccia in un'unica trama tre fili distinti: la propria vicenda personale di uomo e di scienziato, la nascita e lo sviluppo della meccanica quantistica e dei suoi corollari filosofici, la grande storia dal 1920 agli anni sessanta, con il nazismo, la guerra e la pace. Le date che contrassegnano i vari capitoli scandiscono i punti di svolta di un cinquantennio cruciale per i destini dell'Europa e del mondo. Ma ad Heisenberg esse ricordano soprattutto incontri e confronti con altre figure eminenti di scienziati - da Planck ad Einstein, da Bohr a Pauli - che lo intrattengono in dialoghi di stampo platonico sui massimi problemi della scienza, della filosofia e della politica. Prefazione di Eugenio Scalfari.
Manuale di Relatività Ristretta Per la Laurea Triennale in Fisica
Gasperini, Maurizio
2010-01-01
Una moderna presentazione della teoria della Relatività Ristretta, specificatamente progettata per i nuovi corsi della Laurea Triennale in Fisica. Un testo essenziale ma autosufficiente, che adotta lo stile e il linguaggio delle lezioni svolte in aula, e che introduce alle trasformazioni di Lorentz, alla formulazione covariante dell'elettromagnetismo e alle basi della cinematica e dinamica relativistiche. Include una discussione della cinematica dei processi d'urto e una derivazione dettagliata dell'effetto Cherenkov.
The Physical Protection of Nuclear Material; Proteccion Fisica Delos Materiales Nucleares
Energy Technology Data Exchange (ETDEWEB)
NONE
1993-09-15
Physical protection against the theft or unauthorized diversion of nuclear materials and against the sabotage of nuclear facilities by individuals or groups has long been a matter of national and international concern. Although responsibility for establishing and operating a comprehensive physical protection system for nuclear materials and facilities within a State rests entirely with the Government of that State, it is not a matter of indifference to other States whether and to what extent that responsibility is fulfilled. Physical protection has therefore become a matter of international concern and co-operation. The need for international cooperation becomes evident in situations where the effectiveness of physical protection in one State depends on the taking by other States also of adequate measures to deter or defeat hostile actions against nuclear facilities and materials, particularly when such materials are transported across national frontiers [French] La proteccion fisica contra el robo o la desviacion no autorizada de materiales nucleares y contra el sabotaje de las instalaciones nucleares por parte de individuos o de grupos ha sido durante largo tiempo motivo de preocupacion nacional e internacional. Aunque la obligacion de crear y hacer funcionar un sistema completo de proteccion fisica para las instalaciones y materiales nucleares en el territorio de un Estado determinado incumbe enteramente al Gobierno de dicho Estado, el que esa obligacion se cumpla o no, y si se cumple, en que medida o hasta que punto, es cosa que no deja indiferentes a los demas Estados. De aqui que la proteccion fisica se haya convertido en motivo de interes y cooperacion internacional. La necesidad de cooperacion internacional se hace evidente en los casos en que la eficacia de la proteccion fisica en el territorio de un Estado depende de que otros Estados tomen tambien medidas apropiadas para evitar o hacer fracasar los actos hostiles dirigidos contra instalaciones y
Fisica. I progressi nello studio delle particelle piu' abbondanti ma piu mistriose
Bilenky, Samoil Mikhelevich
2003-01-01
"Caccia ai neutrino conferme all'inutizione di Pontecorvo: hanno una masa (sia pure minima) e i loro 3 tipi si mutano l'uno nell'altro fisica i progressi nello studio delle particelle piu' abbondanti ma piu' misteriose". [The hunt for the neutrinos. Pontecorvo's theory has been confirmed: the neutrino has a mass (though minimal). It switches from one of the 3 types into the others].
Fundamental Composite (Goldstone) Higgs Dynamics
DEFF Research Database (Denmark)
Cacciapaglia, G.; Sannino, Francesco
2014-01-01
We provide a unified description, both at the effective and fundamental Lagrangian level, of models of composite Higgs dynamics where the Higgs itself can emerge, depending on the way the electroweak symmetry is embedded, either as a pseudo-Goldstone boson or as a massive excitation of the conden...... searches of new physics at the Large Hadron Collider....
Origins of inert Higgs doublets
Directory of Open Access Journals (Sweden)
Thomas W. Kephart
2016-05-01
Full Text Available We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated Z2 symmetry can occur automatically. Several examples are discussed.
Higgs particle searches at LEP
International Nuclear Information System (INIS)
Martin, J.P.
1996-01-01
Results on searches for the Higgs particle performed by the four LEP experiments are received in the framework of the Standard Model, Two Doublet Model, and Minimal Supersymmetric Model. The combined mass lower limit for the standard Higgs boson is 66 GeV/c 2 at 95 % CL for a statistics of 14.6 Million hadronic Z decays. (authors)
Higgs Portal into Hidden Sectors
CERN. Geneva
2007-01-01
Several attractive theoretical ideas suggest the existence of one or more 'hidden sectors' consisting of standard model singlet fields, some of which may not be too heavy. There is a profound reason to think that the Higgs sector might provide the first access to these hidden sectors. This scenario could affect Higgs phenomenology in drastic ways.
Mariotti, Chiara
2017-01-01
The first measurements of the mass, the width, and the couplings of the newly discovered Higgs boson at LHC at 7 and 8 TeV center of mass energy will be reviewed. Recent results at 13 TeV center of mass energy will be presented. Finally, searches for additional Higgs bosons in models beyond the standard model will be summarised.
International Nuclear Information System (INIS)
Hanninger, Guilherme Nunes
2012-01-01
Full text: The Standard Model of particle physics (SM) has been extremely successful describing the elementary particles and their interactions. It also features a theory describing the origin of particle masses: the 'Higgs mechanism', which postulates the existence of a new particle called the 'Higgs boson'. In 2011 and 2012, tantalising hints of the Higgs boson were reported by the experiments at the Large Hadron Collider (LHC). The results of the search for the Standard Model Higgs Boson with the ATLAS detector in proton-proton collisions at the LHC at 7 and 8 TeV center-of-mass energies are presented. A large number of the Higgs Boson decay channels, such as photon, tau, W and Z pairs, as well as for combined channels in the mass range from 110 GeV to 600 GeV are reviewed and discussed. The combined upper limits on the production cross section as a function of the Higgs Boson mass are derived. Practical methods to estimate the backgrounds using control samples in real data are discussed. Validation of some of the data driven background estimation methods using the early 7 TeV ATLAS data at the LHC is also presented. In addition, searches for Higgs Bosons in scenarios beyond the Standard Model (BSM) lead to improved constraints on the Higgs sector of BSM theories such as Supersymmetry. (author)
Standard model without Higgs particles
International Nuclear Information System (INIS)
Kovalenko, S.G.
1992-10-01
A modification of the standard model of electroweak interactions with the nonlocal Higgs sector is proposed. Proper form of nonlocality makes Higgs particles unobservable after the electroweak symmetry breaking. They appear only as a virtual state because their propagator is an entire function. We discuss some specific consequences of this approach comparing it with the conventional standard model. (author). 12 refs
International Nuclear Information System (INIS)
Dawson, S.
1988-01-01
Experimental limits on light Higgs bosons (M/sub H/ < 5 GeV) are examined. Particular attention is paid to the process K → πH. It is shown that there may be an allowed window for light Higgs bosons between about 100 and 210 MeV. 13 refs., 2 figs
Sasakian and Parabolic Higgs Bundles
Biswas, Indranil; Mj, Mahan
2018-03-01
Let M be a quasi-regular compact connected Sasakian manifold, and let N = M/ S 1 be the base projective variety. We establish an equivalence between the class of Sasakian G-Higgs bundles over M and the class of parabolic (or equivalently, ramified) G-Higgs bundles over the base N.
Future prospects of Higgs Physics at CMS
Marono, Miguel Vidal
2014-01-01
The Higgs boson physics reach of the CMS detector with 300(0) fb-1 of proton-proton collisions at sqrt{s} = 14 TeV is presented. Precision measurements of the Higgs boson properties, Higgs boson pair production and self-coupling, rare Higgs boson decays, and the potential for additional Higgs bosons are discussed. The Higgs boson physics reach of the CMS detector with 300(0) fb-1 of proton-proton collisions at sqrt{s} = 14 TeV is presented. Precision measurements of the Higgs boson propert...
Higgs mass in the gauge-Higgs unification
International Nuclear Information System (INIS)
Haba, Naoyuki; Takenaga, Kazunori; Yamashita, Toshifumi
2005-01-01
The gauge-Higgs unification theory identifies the zero mode of the extra-dimensional component of the gauge field as the usual Higgs doublet. Since this degree of freedom is the Wilson line phase, the Higgs does not have the mass term nor quartic coupling at the tree level. Through quantum corrections, the Higgs can take a vacuum expectation value, and its mass is induced. The radiatively induced mass tends to be small, although it can be lifted to O(100) GeV by introducing the O(10) numbers of bulk fields. Perturbation theory becomes unreliable when a large number of bulk fields are introduced. We reanalyze the Higgs mass based on useful expansion formulae for the effective potential and find that even a small number of bulk field can have the suitable heavy Higgs mass. We show that a small (large) number of bulk fields are enough (needed) when the SUSY breaking mass is large (small). We also study the case of introducing the soft SUSY breaking scalar masses in addition to the Scherk-Schwarz SUSY breaking and obtain the heavy Higgs mass due to the effect of the scalar mass
Handbook of LHC Higgs Cross Sections: 3. Higgs Properties
Energy Technology Data Exchange (ETDEWEB)
Heinemeyer, S; et al.
2013-01-01
This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered particle such as couplings to SM particles, spin and CP-quantum numbers etc.
Mori, T
2001-01-01
As the LEP experiments veriﬁed the gauge interactions more and more rigorously, searches for the Higgs boson, which forms the very basis of the gauge theories, were taking on more and more importance in LEP physics. How this last missing particle in the Standard Model may be discovered (or totally excluded) will be the key to new physics beyond the Standard Model. Here I briefly describe how the LEP experiments together have closed in on this God particle during their 11 year running.
Bluj, Michal Jacek
2018-01-01
In this report we review recent Higgs boson results obtained with pp collisions at $\\sqrt{s}=\\,$13 TeV recorded by the CMS detector in 2016 for an integrated luminosity of 35.9fb$^{\\text{-1}}$. The 2016 data allowed the observation of the $H \\to \\tau\\tau$ and $H \\to WW$ decays with high significance. We also present a combined measurement based on a full set of CMS analyses performed with 2016 data. These results are compatible with the standard model predictions with precision of several measurements exceeding results from combination of ATLAS and CMS data collected in 2011 and 2012.
Grossatesta e la matematica dell'infinitoUna lettura del Commento alla Fisica
Directory of Open Access Journals (Sweden)
Massimiliano Luce
2008-07-01
Full Text Available Un fondamento teologico per la matematica dell'infinito: Dio come primo matematico in grado di numerare gli infiniti punti delle grandezze geometriche. A theological foundation for the mathematics of the infinity: God as the first mathematician, who is able to number the endless points of the geometrical size.
Higgs and confinement phases in the fundamental SU(2) Higgs model: Mean field analysis
International Nuclear Information System (INIS)
Damgaard, P.H.; Heller, U.M.
1985-01-01
The phase diagram of the four-dimensional SU(2) gauge-Higgs model with Higgs field in the fundamental representation is derived by mean field techniques. When the Higgs field is allowed to fluctuate in. Magnitude, the analytic connection between Higgs and confinement phases breaks down for sufficiently small values of the quark Higgs coupling, indicating that the Higgs and confinement phases for these couplings are strictly distinct phases. (orig.)
The Higgs Portal and Cosmology
Energy Technology Data Exchange (ETDEWEB)
Assamagan, Ketevi [Brookhaven National Lab. (BNL), Upton, NY (United States); Chen, Chien-Yi [Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada); Univ. of Victoria, BC (Canada); Chou, John Paul [Rutgers Univ., Piscataway, NJ (United States); Curtin, David [Univ. of Maryland, College Park, MD (United States); Fedderke, Michael A. [Univ. of Chicago, IL (United States); Gershtein, Yuri [Rutgers Univ., Piscataway, NJ (United States); He, Xiao-Gang [Shanghai Jiao Tong Univ. (China); Klute, Markus [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kozaczuk, Jonathon [TRIUMF, Vancouver, BC (Canada); Kotwal, Ashutosh [Duke Univ., Durham, NC (United States); Lowette, Steven [Vrije Univ., Brussels (Belgium); No, Jose Miguel [Univ. of Sussex, Brighton (United Kingdom); Plehn, Tilman [Heidelberg Univ. (Germany); Qian, Jianming [Univ. of Michigan, Ann Arbor, MI (United States); Ramsey-Musolf, Michael [Univ. of Massachusetts, Amherst, MA (United States); Safonov, Alexei [Texas A & M Univ., College Station, TX (United States); Shelton, Jessie [Univ. of Illinois, Urbana-Champaign, IL (United States); Spannowsky, Michael [Durham Univ. (United Kingdom); Su, Shufang [Univ. of Arizona, Tucson, AZ (United States); Walker, Devin G. E. [Univ. of Washington, Seattle, WA (United States); Willocq, Stephane [Univ. of Massachusetts, Amherst, MA (United States); Winslow, Peter [Univ. of Massachusetts, Amherst, MA (United States)
2016-04-18
Higgs portal interactions provide a simple mechanism for addressing two open problems in cosmology: dark matter and the baryon asymmetry. In the latter instance, Higgs portal interactions may contain the ingredients for a strong first-order electroweak phase transition as well as new CP-violating interactions as needed for electroweak baryogenesis. These interactions may also allow for a viable dark matter candidate. We survey the opportunities for probing the Higgs portal as it relates to these questions in cosmology at the LHC and possible future colliders.
Searching for additional Higgs bosons via Higgs cascades
Gao, Christina; Luty, Markus A.; Mulhearn, Michael; Neill, Nicolás A.; Wang, Zhangqier
2018-04-01
The discovery of a 125 GeV Higgs boson at the Large Hadron Collider strongly motivates direct searches for additional Higgs bosons. In a type I two Higgs doublet model there is a large region of parameter space at tan β ≳5 that is currently unconstrained experimentally. We show that the process g g →H →A Z →Z Z h can probe this region, and can be the discovery mode for an extended Higgs sector at the LHC. We analyze 9 promising decay modes for the Z Z h state, and we find that the most sensitive final states are ℓℓℓℓb b , ℓℓj j b b , ℓℓν ν γ γ and ℓℓℓℓ+ missing energy.
Santacruz Sarmiento, Neida M.
Este estudio se enfoco en los "misconception" y lagunas conceptuales en temas fundamentales de Fisica como son Equilibrio Termodinamico y Estatica de fluidos. En primer lugar se trabajo con la identificacion de "misconceptions" y lagunas conceptuales y se analizo en detalle la forma en que los estudiantes construyen sus propias teorias de fenomenos relacionados con los temas. Debido a la complejidad en la que los estudiantes asimilan los conceptos fisicos, se utilizo el metodo de investigacion mixto de tipo secuencial explicativo en dos etapas, una cuantitativa y otra cualitativa. La primera etapa comprendio cuatro fases: (1) Aplicacion de una prueba diagnostica para identificar el conocimiento previo y lagunas conceptuales. (2) Identificacion de "misconceptions" y lagunas del concepto a partir del conocimiento previo. (3) Implementacion de la intervencion por medio de modulos en el topico de Equilibrio Termodinamico y Estatica de Fluidos. (4) Y la realizacion de la pos prueba para analizar el impacto y la efectividad de la intervencion constructivista. En la segunda etapa se utilizo el metodo de investigacion cualitativo, por medio de una entrevista semiestructurada que partio de la elaboracion de un mapa conceptual y se finalizo con un analisis de datos conjuntamente. El desarrollo de este estudio permitio encontrar "misconceptions" y lagunas conceptuales a partir del conocimiento previo de los estudiantes participantes en los temas trabajados, que fueron atendidos en el desarrollo de las distintas actividades inquisitivas que se presentaron en el modulo constructivista. Se encontro marcadas diferencias entre la pre y pos prueba en los temas, esto se debio al requerimiento de habilidades abstractas para el tema de Estatica de Fluidos y al desarrollo intuitivo para el tema de Equilibrio Termodinamico, teniendo mejores respuestas en el segundo. Los participantes demostraron una marcada evolucion y/o cambio en sus estructuras de pensamiento, las pruebas estadisticas
Higgs properties and decays, searches for high mass Higgs boson and di-Higgs production
Cadamuro, Luca
2018-01-01
The study of the scalar sector of the standard model of particle physics is one of the main goals of the LHC physics programme.A precise characterisation of the Higgs boson, searches for extensions of the scalar sector, and the study of Higgs boson pair production are complementary in this exploration.This document describes the status of Higgs boson physics analyses performed by the ATLAS and CMS Collaborations, focusing on the latest results from pp collisions at sqrt(s) = 13 TeV recorded in 2016, for an integrated luminosity of about 36 fb-1.
Energy Technology Data Exchange (ETDEWEB)
Duerr, Michael [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fileviez Perez, Pavel [Case Western Reserve Univ., Cleveland, OH (United States). CERCA, Physics Dept.; Smirnov, Juri [INFN, Sezione di Firenze (Italy); Florence Univ., Sesto Fiorentino (Italy). Dept. of Physics and Astronomy
2017-04-15
We investigate the possible collider signatures of a new Higgs in simple extensions of the Standard Model where baryon number is a local symmetry spontaneously broken at the low scale. We refer to this new Higgs as ''Baryonic Higgs''. This Higgs has peculiar properties since it can decay into all Standard Model particles, the leptophobic gauge boson, and the vector-like quarks present in these theories to ensure anomaly cancellation. We investigate in detail the constraints from the γγ, Zγ, ZZ, and WW searches at the Large Hadron Collider, needed to find a lower bound on the scale at which baryon number is spontaneously broken. The di-photon channel turns out to be a very sensitive probe in the case of small scalar mixing and can severely constrain the baryonic scale. We also study the properties of the leptophobic gauge boson in order to understand the testability of these theories at the LHC.
Supersymmetric Higgs bosons and beyond
International Nuclear Information System (INIS)
Carena, Marcela; Kong, Kyoungchul; Ponton, Eduardo; Zurita, Jose
2010-01-01
We consider supersymmetric models that include particles beyond the minimal supersymmetric standard model (MSSM) with masses in the TeV range, and that couple significantly to the MSSM Higgs sector. We perform a model-independent analysis of the spectrum and couplings of the MSSM Higgs fields, based on an effective theory of the MSSM degrees of freedom. The tree-level mass of the lightest CP-even state can easily be above the LEP bound of 114 GeV, thus allowing for a relatively light spectrum of superpartners, restricted only by direct searches. The Higgs spectrum and couplings can be significantly modified compared to the MSSM ones, often allowing for interesting new decay modes. We also observe that the gluon fusion production cross section of the SM-like Higgs can be enhanced with respect to both the standard model and the MSSM.
Partially composite Goldstone Higgs boson
DEFF Research Database (Denmark)
Alanne, Tommi; Franzosi, Diogo Buarque; Frandsen, Mads T.
2017-01-01
We consider a model of dynamical electroweak symmetry breaking with a partially composite Goldstone Higgs boson. The model is based on a strongly interacting fermionic sector coupled to a fundamental scalar sector via Yukawa interactions. The SU(4)×SU(4) global symmetry of these two sectors...... is broken to a single SU(4) via Yukawa interactions. Electroweak symmetry breaking is dynamically induced by condensation due to the strong interactions in the new fermionic sector which further breaks the global symmetry SU(4)→Sp(4). The Higgs boson arises as a partially composite state which is an exact...... Goldstone boson in the limit where SM interactions are turned off. Terms breaking the SU(4) global symmetry explicitly generate a mass for the Goldstone Higgs boson. The model realizes in different limits both (partially) composite Higgs and (bosonic) technicolor models, thereby providing a convenient...
Phenomenology of the Higgs boson
International Nuclear Information System (INIS)
Ali, A.
1981-09-01
The phenomenology of the standard Weinberg-Salam Higgs boson is reviewed with particular emphasis on production mechanisms in high energy e + e - and hadron-hadron collisions. The production processes relevant for the ISABELLE and TEVATRON energies are discussed and their backgrounds estimated. It is argued that the toponium production and radiative decay provides the most hopeful reaction to detect a Higgs in both the e + e - and the hadron-hadron machines. (orig.)
Phenomenologies of Higgs messenger models
Energy Technology Data Exchange (ETDEWEB)
Zheng Sibo; Yu Yao; Wu Xinggang [Department of Physics, Chongqing University, Chongqing 401331 (China)
2011-08-11
In this Letter, we investigate the phenomenologies of models where the Higgs sector plays the role of messengers in gauge mediation. The minimal Higgs sector and its extension are considered respectively. We find that there exist viable models when an appropriate parity is imposed. Phenomenological features in these kind of models include three sum rules for scalar masses, light gluino as well as one-loop {mu} and two-loop B{mu} terms.
International Nuclear Information System (INIS)
Aranda, A.; Balazs, C.; Diaz-Cruz, J.L.
2003-01-01
Electroweak precision measurements indicate that the standard model Higgs boson is light and that it could have already been discovered at LEP 2, or might be found at the Tevatron run 2. In the context of a TeV -1 size extra-dimensional model, we argue that the Higgs boson production rates at LEP and the Tevatron are suppressed, while they might be enhanced at the LHC or at CLIC. This is due to the possible mixing between brane and bulk components of the Higgs boson, that is, the non-trivial brane-bulk 'location' of the lightest Higgs. To parametrize this mixing, we consider two Higgs doublets, one confined to the usual space dimensions and the other propagating in the bulk. Calculating the production and decay rates for the lightest Higgs boson, we find that compared to the standard model (SM), the cross section receives a suppression well below but an enhancement close to and above the compactification scale M c . This impacts the discovery of the lightest (SM like) Higgs boson at colliders. To find a Higgs signal in this model at the Tevatron run 2 or at the LC with √s=1.5 TeV, a higher luminosity would be required than in the SM case. Meanwhile, at the LHC or at CLIC with √s∼3-5 TeV one might find highly enhanced production rates. This will enable the latter experiments to distinguish between the extra-dimensional and the SM for M c up to about 6 TeV
The Nobel Prize winner in physics 2013--Peter Higgs
International Nuclear Information System (INIS)
Liu Jinyan
2014-01-01
Peter Higgs is a famous English physicist who was known for his works on Higgs mechanism and Higgs particle. He won the 2013 Noble Prize in physics. This paper briefly outlines his life, the proposition of Higgs mechanism and the origin of the name of Higgs particle. The discovery of Higgs particle is also given here. (author)
International Nuclear Information System (INIS)
Gregoire, Thomas; Wacker, Jay G.
2002-01-01
New theories of electroweak symmetry breaking have recently been constructed that stabilize the weak scale and do not rely upon supersymmetry. In these theories the Higgs boson is a weakly coupled pseudo-Goldstone boson. In this note we study the class of theories that can be described by theory spaces and show that the fundamental group of theory space describes all the relevant classical physics in the low energy theory. The relationship between the low energy physics and the topological properties of theory space allow a systematic method for constructing theory spaces that give any desired low energy particle content and potential. This provides us with tools for analyzing and constructing new theories of electroweak symmetry breaking. (author)
Searches for BSM Higgs Bosons with ATLAS
Navarro, Gabriela; The ATLAS collaboration
2015-01-01
The discovery of a Higgs-like boson with a mass of about 125GeV has prompted the question of whether or not this particle is part of a much larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS Experiment regarding Beyond-the-Standard Model (BSM) Higgs hypothesis tests are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal Supersymmetric Standard Model.
Vacuum stability in neutrinophilic Higgs doublet model
International Nuclear Information System (INIS)
Haba, Naoyuki; Horita, Tomohiro
2011-01-01
A neutrinophilic Higgs model has tiny vacuum expectation value (VEV), which can naturally explain tiny masses of neutrinos. There is a large energy scale hierarchy between a VEV of the neutrinophilic Higgs doublet and that of usual standard model-like Higgs doublet. In this Letter we at first analyze vacuum structures of Higgs potential in both supersymmetry (SUSY) and non-SUSY neutrinophilic Higgs models, and next investigate a stability of this VEV hierarchy against radiative corrections. We will show that the VEV hierarchy is stable against radiative corrections in both Dirac neutrino and Majorana neutrino scenarios in both SUSY and non-SUSY neutrinophilic Higgs doublet models.
Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson ...
Indian Academy of Sciences (India)
We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tan and A. We observe that at fixed ...
Invisible Higgs decays from Higgs-graviscalar mixing
International Nuclear Information System (INIS)
Dominici, Daniele; Gunion, John F.
2009-01-01
We recompute the invisible Higgs decay width arising from Higgs-graviscalar mixing in the Arkani-Hamed, Dimopoulos, Dvali model, comparing the original derivation in the nondiagonal mass basis to that in a diagonal mass basis. The results obtained are identical (and differ by a factor of 2 from the original calculation) but the diagonal-basis derivation is pedagogically useful for clarifying the physics of the invisible width from mixing. We emphasize that both derivations make it clear that a direct scan in energy for a process such as WW→WW mediated by Higgs plus graviscalar intermediate resonances would follow a single Breit-Wigner form with total width given by Γ tot =Γ h SM +Γ invisible . We also compute the additional contributions to the invisible width due to direct Higgs to graviscalar-pair decays. We find that the invisible width due to the latter is relatively small, unless the Higgs mass is comparable to or larger than the effective extra-dimensional Planck mass.
The search for a heavy Higgs boson
International Nuclear Information System (INIS)
Dawson, S.
1989-02-01
Theoretical limits on the mass of the Higgs boson from vacuum stability and perturbative unitarity are examined. Search techniques for heavy Higgs bosons, M/sub H/ > 200 GeV, are also reviewed. 8 refs., 5 figs
Higgs Particle: The Origin of Mass
Okada, Yasuhiro
2007-01-01
The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments, LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generat...
THE HIGGS WORKING GROUP: SUMMARY REPORT.
Energy Technology Data Exchange (ETDEWEB)
DAWSON, S.; ET AL.
2005-08-01
This working group has investigated Higgs boson searches at the Tevatron and the LHC. Once Higgs bosons are found their properties have to be determined. The prospects of Higgs coupling measurements at the LHC and a high-energy linear e{sup +}e{sup -} collider are discussed in detail within the Standard Model and its minimal supersymmetric extension (MSSM). Recent improvements in the theoretical knowledge of the signal and background processes are presented and taken into account. The residual uncertainties are analyzed in detail. Theoretical progress is discussed in particular for the gluon-fusion processes gg {yields} H(+j), Higgs-bremsstrahlung off bottom quarks and the weak vector-boson-fusion (VBF) processes. Following the list of open questions of the last Les Houches workshop in 2001 several background processes have been calculated at next-to-leading order, resulting in a significant reduction of the theoretical uncertainties. Further improvements have been achieved for the Higgs sectors of the MSSM and NMSSM. This report summarizes our work performed before and after the workshop in Les Houches. Part A describes the theoretical developments for signal and background processes. Part B presents recent progress in Higgs boson searches at the Tevatron collider. Part C addresses the determination of Higgs boson couplings, part D the measurement of tan {beta} and part E Higgs boson searches in the VBF processes at the LHC. Part F summarizes Higgs searches in supersymmetric Higgs decays, part G photonic Higgs decays in Higgs-strahlung processes at the LHC, while part H concentrates on MSSM Higgs bosons in the intense-coupling regime at the LHC. Part I presents progress in charged Higgs studies and part J the Higgs discovery potential in the NMSSM at the LHC. The last part K describes Higgs coupling measurements at a 1 TeV linear e{sup +}e{sup -} collider.
THE HIGGS WORKING GROUP: SUMMARY REPORT
International Nuclear Information System (INIS)
DAWSON, S.
2005-01-01
This working group has investigated Higgs boson searches at the Tevatron and the LHC. Once Higgs bosons are found their properties have to be determined. The prospects of Higgs coupling measurements at the LHC and a high-energy linear e + e - collider are discussed in detail within the Standard Model and its minimal supersymmetric extension (MSSM). Recent improvements in the theoretical knowledge of the signal and background processes are presented and taken into account. The residual uncertainties are analyzed in detail. Theoretical progress is discussed in particular for the gluon-fusion processes gg → H(+j), Higgs-bremsstrahlung off bottom quarks and the weak vector-boson-fusion (VBF) processes. Following the list of open questions of the last Les Houches workshop in 2001 several background processes have been calculated at next-to-leading order, resulting in a significant reduction of the theoretical uncertainties. Further improvements have been achieved for the Higgs sectors of the MSSM and NMSSM. This report summarizes our work performed before and after the workshop in Les Houches. Part A describes the theoretical developments for signal and background processes. Part B presents recent progress in Higgs boson searches at the Tevatron collider. Part C addresses the determination of Higgs boson couplings, part D the measurement of tan β and part E Higgs boson searches in the VBF processes at the LHC. Part F summarizes Higgs searches in supersymmetric Higgs decays, part G photonic Higgs decays in Higgs-strahlung processes at the LHC, while part H concentrates on MSSM Higgs bosons in the intense-coupling regime at the LHC. Part I presents progress in charged Higgs studies and part J the Higgs discovery potential in the NMSSM at the LHC. The last part K describes Higgs coupling measurements at a 1 TeV linear e + e - collider
International Nuclear Information System (INIS)
Franzini, P.J.
1986-04-01
Bounds from B 0 - anti B 0 mixing on charged-Higgs-boson masses and couplings in two-Higgs-doublet models are presented. These bounds are comparable to those obtained, with additional assumptions, from the neutral-K-system. The effects of the neutral Higgs bosons of these models on the spectrum and wave function of toponium are discussed. These effects could, in the future, lead to limits on, or the discovery of, these Higgs bosons. 8 refs., 3 figs
HiggsSignals. Confronting arbitrary Higgs sectors with measurements at the Tevatron and the LHC
Energy Technology Data Exchange (ETDEWEB)
Bechtle, Philip [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). The Oskar Klein Centre; Stefaniak, Tim [Bonn Univ. (Germany). Physikalisches Inst.; Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2013-05-15
HiggsSignals is a Fortran90 computer code that allows to test the compatibility of Higgs sector predictions against Higgs rates and masses measured at the LHC or the Tevatron. Arbitrary models with any number of Higgs bosons can be investigated using a model-independent input scheme based on HiggsBounds. The test is based on the calculation of a {chi}{sup 2} measure from the predictions and the measured Higgs rates and masses, with the ability of fully taking into account systematics and correlations for the signal rate predictions, luminosity and Higgs mass predictions. It features two complementary methods for the test. First, the peak-centered method, in which each observable is defined by a Higgs signal rate measured at a specific hypothetical Higgs mass, corresponding to a tentative Higgs signal. Second, the mass-centered method, where the test is evaluated by comparing the signal rate measurement to the theory prediction at the Higgs mass predicted by the model. The program allows for the simultaneous use of both methods, which is useful in testing models with multiple Higgs bosons. The code automatically combines the signal rates of multiple Higgs bosons if their signals cannot be resolved by the experimental analysis. We compare results obtained with HiggsSignals to official ATLAS and CMS results for various examples of Higgs property determinations and find very good agreement. A few examples of HiggsSignals applications are provided, going beyond the scenarios investigated by the LHC collaborations. For models with more than one Higgs boson we recommend to use HiggsSignals and HiggsBounds in parallel to exploit the full constraining power of Higgs search exclusion limits and the measurements of the signal seen at m{sub H} {approx} 125.5 GeV.
Higgs friends and counterfeits at hadron colliders
International Nuclear Information System (INIS)
Fox, Patrick J.; Tucker-Smith, David; Weiner, Neal
2011-01-01
We consider the possibility of 'Higgs counterfeits' - scalars that can be produced with cross sections comparable to the SM Higgs, and which decay with identical relative observable branching ratios, but which are nonetheless not responsible for electroweak symmetry breaking. We also consider a related scenario involving 'Higgs friends,' fields similarly produced through gg fusion processes, which would be discovered through diboson channels WW,ZZ,γγ, or even γZ, potentially with larger cross sections times branching ratios than for the Higgs. The discovery of either a Higgs friend or a Higgs counterfeit, rather than directly pointing towards the origin of the weak scale, would indicate the presence of new colored fields necessary for the sizable production cross section (and possibly new colorless but electroweakly charged states as well, in the case of the diboson decays of a Higgs friend). These particles could easily be confused for an ordinary Higgs, perhaps with an additional generation to explain the different cross section, and we emphasize the importance of vector boson fusion as a channel to distinguish a Higgs counterfeit from a true Higgs. Such fields would naturally be expected in scenarios with 'effective Z's,' where heavy states charged under the SM produce effective charges for SM fields under a new gauge force. We discuss the prospects for discovery of Higgs counterfeits, Higgs friends, and associated charged fields at the LHC.
Goldstone bosons and a dynamical Higgs field
Mooij, S.; Postma, M.
2011-01-01
Higgs inflation uses the gauge variant Higgs field as the inflaton. During inflation the Higgs field is displaced from its minimum, which results in associated Goldstone bosons that are apparently massive. Working in a minimally coupled U(1) toy model, we use the closed-time-path formalism to show
Higgs physics at the Large Hadron Collider
Indian Academy of Sciences (India)
Higgs boson; Large Hadron Collider; electroweak symmetry; spin and CP of the Higgs boson ... I shall then give a short description of the pre-LHC constraints on the Higgs mass and the theoretical predictions for the LHC along with a discussion of the current experimental results, ending with prospects in the near future at ...
Introduction to the physics of Higgs bosons
International Nuclear Information System (INIS)
Dawson, S.
1994-11-01
A basic introduction to the physics of the Standard Model Higgs boson is given. We discuss Higgs boson production in e + e - and hadronic collisions and survey search techniques at future accelerators. The Higgs bosons of the minimal SUSY model are briefly considered. Indirect limits from triviality arguments, vacuum stability and precision measurements at LEP are also presented
Higgs into the heart of imagination
Van den Bergh, Hannie
2010-01-01
Higgs is the documentary about the quest for the Higgs particle, also known as "The God Particle". It is considered the missing link in particle physics. Higgs is a film about the curiosity, the passion, and the imaginative power of silence.
Higgs bosons in extra dimensions
Quiros, Mariano
2015-05-01
In this paper, motivated by the recent discovery of a Higgs-like boson at the Large Hadron Collider (LHC) with a mass mH≃125 GeV, we review different models where the hierarchy problem is solved by means of a warped extra dimension. In the Randall-Sundrum (RS) model electroweak observables provide very strong bounds on the mass of KK modes which motivates extensions to overcome this problem. Two extensions are briefly discussed. One particular extension is based on the deformation of the metric such that it strongly departs from the AdS5 structure in the IR region while it goes asymptotically to AdS5 in the UV brane. This model has the IR brane close to a naked metric singularity (which is outside the physical interval) characteristic of soft-walls constructions. The proximity of the singularity provides a strong wave function renormalization for the Higgs field which suppresses the T and S parameters. The second class of considered extensions are based on the introduction of an extra gauge group in the bulk such that the custodial SU(2)R symmetry is gauged and protects the T parameter. By further enlarging the bulk gauge symmetry one can find models where the Higgs is identified with the fifth component of gauge fields and for which the Higgs potential along with the Higgs mass can be dynamically determined by the Coleman-Weinberg mechanism.
The Higgs of the Higgs and the diphoton channel
Kannike, Kristjan
2016-07-20
LHC results do not confirm conventional natural solutions to the Higgs mass hierarchy problem, motivating alternative interpretations where a hierarchically small weak scale is generated from a dimension-less quantum dynamics. We propose weakly and strongly-coupled models where the field that breaks classical scale invariance giving mass to itself and to the Higgs is identified with a possible new resonance within the LHC reach. As an example, we identify such resonance with the 750 GeV diphoton excess recently reported by ATLAS and CMS. Such models can be extrapolated up to the Planck scale, provide Dark Matter candidates and eliminate the SM vacuum instability.
Energy Technology Data Exchange (ETDEWEB)
Ema, Yohei [Department of Physics, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Karčiauskas, Mindaugas [University of Jyväskylä, Department of Physics, P.O. Box 35 (YFL), FI-40014, Jyväskylä (Finland); Lebedev, Oleg; Zatta, Marco, E-mail: ema@hep-th.phys.s.u-tokyo.ac.jp, E-mail: mindaugas.m.karciauskas@jyu.fi, E-mail: oleg.lebedev@helsinki.fi, E-mail: marco.zatta@helsinki.fi [University of Helsinki and Helsinki Institute of Physics, P.O. Box 64, FI-00014, Helsinki (Finland)
2017-06-01
Apparent metastability of the electroweak vacuum poses a number of cosmological questions. These concern evolution of the Higgs field to the current vacuum, and its stability during and after inflation. Higgs-inflaton and non-minimal Higgs-gravity interactions can make a crucial impact on these considerations potentially solving the problems. In this work, we allow for these couplings to be present simultaneously and study their interplay. We find that different combinations of the Higgs-inflaton and non-minimal Higgs-gravity couplings induce effective Higgs mass during and after inflation. This crucially affects the Higgs stability considerations during preheating. In particular, a wide range of the couplings leading to stable solutions becomes allowed.
De Curtis, Stefania; Tesi, Andrea
2012-01-01
We propose a four dimensional description of Composite Higgs Models which represents a complete framework for the physics of the Higgs as a pseudo-Nambu-Goldstone boson. Our setup captures all the relevant features of 5D models and more in general of composite Higgs models with partial compositeness. We focus on the minimal scenario where we include a single multiplet of resonances of the composite sector, as these will be the only degrees of freedom which might be accessible at the LHC. This turns out to be sufficient to compute the effective potential and derive phenomenological consequences of the theory. Moreover our simplified approach is well adapted to simulate these models at the LHC. We also consider the impact of non-minimal terms in the effective lagrangian which do not descend from a 5D theory and could be of phenomenological relevance, for example contributing to the S-parameter.
Semialigned two Higgs doublet model
Haba, Naoyuki; Umeeda, Hiroyuki; Yamada, Toshifumi
2018-02-01
In the left-right symmetric model based on S U (2 )L×S U (2 )R×U (1 )B -L gauge symmetry, there appear heavy neutral scalar particles mediating quark flavor changing neutral currents (FCNCs) at tree level. We consider a situation where such FCNCs give the only sign of the left-right model while WR gauge boson is decoupled, and name it "semialigned two Higgs doublet model" because the model resembles a two Higgs doublet model with mildly aligned Yukawa couplings to quarks. We predict a correlation among processes induced by quark FCNCs in the model, and argue that future precise calculation of meson-antimeson mixings and C P violation therein may hint at the semialigned two Higgs doublet model and the left-right model behind it.
Four generations and Higgs physics
Energy Technology Data Exchange (ETDEWEB)
Kribs, Graham D. [Department of Physics and Institute of Theoretical Science, University of Oregon, Eugene (United States); Plehn, Tilman [SUPA, School of Physics, University of Edinburgh (United Kingdom); Spannowsky, Michael [Institut fuer Theoretische Physik, Universitaet Karlsruhe (Germany); Tait, Tim M.P. [HEP Division, Argonne National Laboratory (United States)
2008-07-01
A fourth generation has been considered and forgotten or discarded several times, wrongly leaving the impression that it is either ruled out or disfavored by experimental data. We revisit a fourth generation of chiral matter in the light of present electroweak precision data and deduce effects on Higgs phenomenology. We find a chiral fourth generation to be a viable model which can yield interesting signatures at the LHC, e.g. production rates are enhanced, weak-boson-fusion channels are suppressed, angular distributions are modified and Higgs pairs can be observed.
International Nuclear Information System (INIS)
Low, I.; Schwaller, P.; Shaughnessy, G.; Wagner, C.E.M.
2012-01-01
Current limits from the Large Hadron Collider exclude a standard model-like Higgs mass above 150 GeV, by placing an upper bound on the Higgs production rate. We emphasize that, alternatively, the limit could be interpreted as a lower bound on the total decay width of the Higgs boson. If the invisible decay width of the Higgs is of the same order as the visible decay width, a heavy Higgs boson could be consistent with null results from current searches. We propose a method to infer the invisible decay of the Higgs by using the width of the measured h → ZZ → 4 (ell) line shape, and study the effect on the width extraction due to a reduced signal strength. Assuming the invisible decay product is the dark matter, we show that minimal models are tightly constrained by limits from Higgs searches at the LHC and direct detection experiments of dark matter, unless the relic density constraint is relaxed.
Higgs searches and prospects at CDF
International Nuclear Information System (INIS)
Pavel A Murat
2003-01-01
The Standard model of electroweak interactions (SM) has been extremely successful in describing interactions of elementary particles over the last decades. The Higgs scalar boson is one of the key elements of the SM: Higgs interactions with the other particles generate the particle masses and allow to keep the theory renormalizable at electroweak scale. All the particles predicted by the SM but the Higgs boson have already been observed experimentally and therefore search for the Higgs is one of the most important scientific goals for high energy physics. The current lower limit on the SM Higgs mass M H > 114.4 GeV at 95% CL has been established by LEP experiments. In this paper we review CDF Run I results on Higgs searches including the Higgs bosons predicted by the minimal supersymmetric extention of the Standard Model (MSSM) and discuss the Run II prospects
Higgs-Palatini inflation and unitarity
International Nuclear Information System (INIS)
Bauer, Florian; Demir, Durmus A.
2011-01-01
In the Higgs inflation scenario the Higgs field is strongly coupled to the Ricci scalar in order to drive primordial inflation. However, in its original form in pure metric formulation of gravity, the ultraviolet (UV) cutoff of the Higgs interactions and the Hubble rate are of the same magnitude, and this makes the whole inflationary evolution dependent of the unknown UV completion of the Higgs sector. This problem, the unitarity violation, plagues the Higgs inflation scenario. In this Letter we show that, in the Palatini formulation of gravitation, Higgs inflation does not suffer from unitarity violation since the UV cutoff lies parametrically much higher than the Hubble rate so that unknown UV physics does not disrupt the inflationary dynamics. Higgs-Palatini inflation, as we call it, is, therefore, UV-safe, minimal and endowed with predictive power.
Incontri di Fisica delle Alte Energie Italian Meeting on High Energy Physics Napoli
Carlino, Gianpaolo; Merola, Leonardo; Paolucci, Pierluigi; Ricciardi, Giulia; IFAE 2007
2008-01-01
This book collects the Proceedings of the Workshop "Incontri di Fisica delle Alte Energie (IFAE) 2007, Napoli, 11-13 April 2007". This is the sixth edition of a series of meetings on fundamental research in particle physics and was attended by about 160 researchers. Presentations, both theoretical and experimental, addressed the status of Physics of the Standard Model and beyond, Flavour phyisc, Neutrino and Astroparticle physics, new technology in high energy physics. Special emphasis was given to the expectations of the forthcoming Large Hadron Collider, due in operation at the end of 2007. The venue of plenary sessions interleaved with parallel ones allowed for a rich exchange of ideas, presented in these Proceedings, that form a coherent picture of the findings and of the open questions in this extremely challenging cultural field. The venue of plenary sessions interleaved with parallel ones allowed for a rich exchange of ideas, presented in these Proceedings, that form a coherent picture of the findings ...
LEP Higgs boson searches beyond the standard model
Indian Academy of Sciences (India)
These include the searches for charged Higgs bosons, models with two Higgs field doublets, searches for 'fermiophobic' Higgs decay, invisible Higgs boson decays, decay-mode independent searches, and limits on Yukawa and anomalous Higgs couplings. I review the searches done by the four LEP experiments and ...
2016-01-01
A subject of major importance in fundamental physics is the investigation of the origin of Electroweak Symmetry Breaking. The mechanism of mass generation through the spontaneous breaking of a gauge symmetry is called the Brout-Englert-Higgs mechanism and is associated with the appearance of a physical scalar boson. The discovery announced at CERN on 4th July 2012 by the ATLAS and CMS Collaborations of a boson at a mass close to 125 GeV/c2, compatible with this scalar boson of the Standard Model, the so-called Higgs boson, mainly in γγ, ZZ and WW decay modes, with compatible evidence also found at Fermilab in the bb mode, changed the landscape. This important discovery was acknowledged as decisive for the attribution of the 2013 Nobel Prize in Physics awarded jointly to François Englert and Peter Higgs . This 7th workshop of the "Higgs Hunting" series organized in Paris on August 31 - September 2, 2016 will discuss the developments of LHC run 2 analyses, detailed studies of the new boson and possible de...
New ATLAS Higgs physics results
CERN. Geneva
2014-01-01
New Higgs physics results from the ATLAS experiment using the full Run-1 LHC dataset, corresponding to an integrated luminosity of approximately 25 fb-1, of proton-proton collisions at 7 TeV and 8 TeV, will be presented.
Higgs mass determination in supersymmetry
Energy Technology Data Exchange (ETDEWEB)
Vega, Javier Pardo [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy); SISSA International School for Advanced Studies and INFN Trieste, Via Bonomea 265, 34136, Trieste (Italy); Villadoro, Giovanni [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy)
2015-07-29
We present the state-of-the-art of the effective field theory computation of the MSSM Higgs mass, improving the existing ones by including extra threshold corrections. We show that, with this approach, the theoretical uncertainty is within 1 GeV in most of the relevant parameter space. We confirm the smaller value of the Higgs mass found in the EFT computations, which implies a slightly heavier SUSY scale. We study the large tan β region, finding that sbottom thresholds might relax the upper bound on the scale of SUSY. We present SUSYHD, a fast computer code that computes the Higgs mass and its uncertainty for any SUSY scale, from the TeV to the Planck scale, even in Split SUSY, both in the (DR)-bar and in the on-shell schemes. Finally, we apply our results to derive bounds on some well motivated SUSY models, in particular we show how the value of the Higgs mass allows to determine the complete spectrum in minimal gauge mediation.
International Nuclear Information System (INIS)
Sutherland, D.G.
2005-01-01
Most recent models assuming the Higgs boson is a pseudo-Nambu-Goldstone boson (pNGb) are motivated by the indication from Standard Model fits that its mass is = SU(3) model we use is briefly discussed. Some potential theoretical and phenomenological problems are mentioned briefly
The Higgs boson and cosmology.
Shaposhnikov, Mikhail
2015-01-13
I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.
Higgs boson properties in ATLAS
Mansoulie, Bruno; The ATLAS collaboration
2017-01-01
The measurement by the ATLAS collaboration of Higgs boson properties is presented, in terms of production cross-sections, simplified template cross-sections, couplings. The measurements are based on the analysis of the H decay channels to diphoton and 4 leptons, using 36.1 fb-1 of 13 TeV data recorded in 2015 and 2016.
Frequently Asked Questions: The Higgs!
CERN Bulletin
2012-01-01
Why have we tried so hard to find the Higgs particle? How does the Higgs mechanism work? What is the difference in physics between strong evidence and a discovery? Why do physicists speak in terms of "sigmas"? Find out here! Why have we tried so hard to find the Higgs particle? Because it could be the answer to the question: how does Nature decide whether or not to assign mass to particles? All the fundamental particles making up matter – the electron, the quarks, etc. – have masses. Moreover, quantum physics requires that forces are also carried by particles. The W and Z particles that carry the weak force responsible for radioactivity must also have masses, whereas the photon, the carrier of the electromagnetic force, has no mass at all. This is the root of the “Higgs problem”: how to give masses to the fundamental particles and break the symmetry between the massive W and Z and the massless photon? Just assigning masses by hand...
Shaposhnikov, Mikhail
2015-01-01
I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.
Energy Technology Data Exchange (ETDEWEB)
Maldonado, J. L. [Centro de Investigacion en Optica, Leon, Guanajuato (Mexico); Garcia M, J. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)
2001-12-01
This paper is a review about the new photo refractive organic materials and their potential photonic applications, the photo refractive polymers. The physical properties required for observing photo refractivity, including charge generation, transport, and nonlinear optical properties are discussed for amorphous polymers. The nonlinear optical properties on a macroscopic level are related to the microscopic properties by using the Oriented Gas model. Four Wave Mixing (FWM) and Two Beam Coupling (TBC) experiments, to investigate the photo refractive properties of the material by measuring the diffraction efficiency {eta} of the polymeric gratings, and the optical gain coefficient {eta} are described. Kogelnik's Coupled Wave model to describe the photo refractive polymeric gratings is reviewed. Finally some applications of these new polymers are presented. [Spanish] Este articulo es una revision sobre los nuevos materiales organicos fotorrrefractivos y sus potenciales aplicaciones fotonicas: los polimeros fotorrefractivos. Se discuten las propiedades fisicas requeridas para observar fotorrefractividad, incluyendo la generacion de cargas, el transporte y las propiedades opticas no lineales en polimeros amorfos. Usando el modelo de gas orientado, se muestra como se relacionan las propiedades opticas no lineales a nivel marcoscopico con las propiedades microscopicas. Se describen los experimentos de mezcla de cuatro ondas (FWM) y dos ondas (TBC) para investigar las propiedades fotorrefractivas del material, midiendo la eficiencia de difraccion {eta} de las rejillas polimericas y el coeficiente de ganancia optica {eta}. Se revisa el modelo de ondas acopladas de Kogelnik para describir las rejillas polimericas fotorrefractivas. Finalmente se presentan algunas aplicaciones de estos nuevos polimeros.
Effect of multiple Higgs fields on the phase structure of the SU(2)-Higgs model
International Nuclear Information System (INIS)
Wurtz, Mark; Steele, T. G.; Lewis, Randy
2009-01-01
The SU(2)-Higgs model, with a single Higgs field in the fundamental representation and a quartic self-interaction, has a Higgs region and a confinement region which are analytically connected in the parameter space of the theory; these regions thus represent a single phase. The effect of multiple Higgs fields on this phase structure is examined via Monte Carlo lattice simulations. For the case of N≥2 identical Higgs fields, there is no remaining analytic connection between the Higgs and confinement regions, at least when Lagrangian terms that directly couple different Higgs flavors are omitted. An explanation of this result in terms of enhancement from overlapping phase transitions is explored for N=2 by introducing an asymmetry in the hopping parameters of the Higgs fields. It is found that an enhancement of the phase transitions can still occur for a moderate (10%) asymmetry in the resulting hopping parameters.
Higher-order corrected Higgs bosons in FeynHiggs2.4
Indian Academy of Sciences (India)
treatment of loop-corrected Higgs-boson mass eigenstates as external (on-shell) or internal .... This gives rise to finite wave function normalization factors. [22]. .... The elements of Un can be interpreted as effective couplings of internal Higgs.
Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider
International Nuclear Information System (INIS)
Singhal, Jai Kumar; Singh, Sardar; Nagawat, Ashok K.
2007-01-01
We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tanβ and m A . We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson. (author)
Smoking-gun signatures for little Higgs models
International Nuclear Information System (INIS)
Han, Tao
2004-01-01
The little Higgs idea is a new way to solve the 'little hierarchy' problem by protecting the Higgs mass from quadratically divergent one-loop corrections. After a general introduction, I first describe the Littlest Higgs model to illustrate the little Higgs idea. I then present certain phenomenological signatures of two classes of little Higgs theories for future colliders. I emphasize to test the cancellation mechanism and how to distinguish different little Higgs models. (author)
Finding the Higgs boson: A status report
International Nuclear Information System (INIS)
Dawson, S.
1995-01-01
The search for the Higgs boson of the minimal Standard Model has been a major focus of experimental high energy physics for some years now. Here, the authors review the current experimental limits and discuss the prospects for finding the Higgs boson at future accelerators, such as LEPII and the LHC. They consider only the Standard Model Higgs boson. Since a null result which definitively excluded a Higgs boson below some mass scale would be extremely important, they emphasize the case where the Higgs boson is much heavier than the relevant collider energy (or where there is no Higgs boson at all). Many of the results given here are a summary of those obtained by the DPF Committee on Long Term Planning
Collider signatures of flavorful Higgs bosons
International Nuclear Information System (INIS)
Altmannshofer, Wolfgang; Eby, Joshua; Gori, Stefania; Lotito, Matteo
2016-01-01
Motivated by our limited knowledge of the Higgs couplings to the first two generation fermions, we analyze the collider phenomenology of a class of two Higgs doublet models (2HDMs) with a nonstandard Yukawa sector. One Higgs doublet is mainly responsible for the masses of the weak gauge bosons and the third-generation fermions, while the second Higgs doublet provides mass for the lighter fermion generations. The characteristic collider signatures of this setup differ significantly from well-studied 2HDMs with natural flavor conservation, flavor alignment, or minimal flavor violation. New production mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving second-generation quarks can become dominant. The most interesting decay modes include H/A → cc,tc,μμ,τμ and H"± → cb,cs,μν. As a result, searches for low-mass dimuon resonances are currently among the best probes of the heavy Higgs bosons in this setup.
A Historical Profile of the Higgs Boson
Energy Technology Data Exchange (ETDEWEB)
Ellis, John; Gaillard, Mary K.; Nanopoulos, Dimitri V.
2012-01-31
The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible productionin e{sup +} e{sup -}, {anti p}p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented bysearches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs bosonis accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.
Effective Field Theory with Two Higgs Doublets
Crivellin, Andreas; Procura, Massimiliano
2016-01-01
In this article we extend the effective field theory framework describing new physics effects to the case where the underlying low-energy theory is a Two-Higgs-Doublet model. We derive a complete set of independent operators up to dimension six assuming a $Z_2$-invariant CP-conserving Higgs potential. The effects on Higgs and gauge boson masses, mixing angles in the Higgs sector as well as couplings to fermions and gauge bosons are computed. At variance with the case of a single Higgs doublet, we find that pair production of SM-like Higgses, arising through dimension-six operators, is not fixed by fermion-fermion-Higgs couplings and can therefore be sizable.
Machine Learning wins the Higgs Challenge
Abha Eli Phoboo
2014-01-01
The winner of the four-month-long Higgs Machine Learning Challenge, launched on 12 May, is Gábor Melis from Hungary, followed closely by Tim Salimans from the Netherlands and Pierre Courtiol from France. The challenge explored the potential of advanced machine learning methods to improve the significance of the Higgs discovery. Winners of the Higgs Machine Learning Challenge: Gábor Melis and Tim Salimans (top row), Tianqi Chen and Tong He (bottom row). Participants in the Higgs Machine Learning Challenge were tasked with developing an algorithm to improve the detection of Higgs boson signal events decaying into two tau particles in a sample of simulated ATLAS data* that contains few signal and a majority of non-Higgs boson “background” events. No knowledge of particle physics was required for the challenge but skills in machine learning - the training of computers to recognise patterns in data – were essential. The Challenge, hosted by Ka...
Extended Higgs sectors in radiative neutrino models
Directory of Open Access Journals (Sweden)
Oleg Antipin
2017-05-01
Full Text Available Testable Higgs partners may be sought within the extensions of the SM Higgs sector aimed at generating neutrino masses at the loop level. We study a viability of extended Higgs sectors for two selected models of radiative neutrino masses: a one-loop mass model, providing the Higgs partner within a real triplet scalar representation, and a three-loop mass model, providing it within its two-Higgs-doublet sector. The Higgs sector in the one-loop model may remain stable and perturbative up to the Planck scale, whereas the three-loop model calls for a UV completion around 106 GeV. Additional vector-like lepton and exotic scalar fields, which are required to close one- and three-loop neutrino-mass diagrams, play a decisive role for the testability of the respective models. We constrain the parameter space of these models using LHC bounds on diboson resonances.
Graceful exit from Higgs G-inflation
Energy Technology Data Exchange (ETDEWEB)
Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tsutomu [Rikkyo Univ., Tokyo (Japan). Dept. of Physics; Kunimitsu, Taro [Tokyo Univ. (Japan). Dept. of Physics; Tokyo Univ. (Japan). Research Center for the Early Universe (RESCEU); Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics; Yokoyama, Jun' ichi [Tokyo Univ. (Japan). Research Center for the Early Universe (RESCEU); Tokyo Univ., Chiba (Japan). Kavli Inst. for the Physics and Mathematics of the Universe (Kavli IPMU)
2013-09-15
Higgs G-inflation is a Higgs inflation model with a generalized Galileon term added to the standard model Higgs field, which realizes inflation compatible with observations. Recently, it was claimed that the generalized Galileon term induces instabilities during the oscillation phase, and that the simplest Higgs G-inflation model inevitably suffers from this problem. In this paper, we extend the original Higgs G-inflation Lagrangian to a more general form, namely introducing a higher-order kinetic term and generalizing the form of the Galileon term, so that the Higgs field can oscillate after inflation without encountering instabilities. Moreover, it accommodates a large region of the n{sub s}-r plane, most of which is consistent with current observations, leading us to expect the detection of B-mode polarization in the cosmic microwave background in the near future.
Higgs bosons in supersymmetric models. Pt. 1
International Nuclear Information System (INIS)
Gunion, J.F.
1986-01-01
We describe the properties of Higgs bosons in a class of supersymmetric theories. We consider models in which the low-energy sector contains two weak complex doublets and perhaps one complex gauge-singlet Higgs field. Supersymmetry is assumed to be either softly or spontaneously broken, thereby imposing a number of restrictions on the Higgs boson parameters. We elucidate the Higgs boson masses and present Feynman rules for their couplings to the gauge bosons, fermions and scalars of the theory. We also present Feynman rules for vertices which are related by supersymmetry to the above couplings. Exact analytic expressions are given in two useful limits - one corresponding to the absence of the gauge-singlet Higgs field and the other corresponding to the absence of a supersymmetric Higgs mass term. (orig.)
Cosmological perturbations in the new Higgs inflation
Energy Technology Data Exchange (ETDEWEB)
Germani, Cristiano [Arnold Sommerfeld Center, Ludwig-Maximilians-University, Theresienstr, 37 80333 Muenchen (Germany); Kehagias, Alex, E-mail: cristiano.germani@lmu.de, E-mail: kehagias@central.ntua.gr [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece)
2010-05-01
We study the cosmological perturbations created during the New Higgs inflationary phase. In the New Higgs Inflation, the Higgs boson is kinetically coupled to the Einstein tensor and only three perturbative degrees of freedom, a scalar and two tensorial (gravitational waves), propagate during Inflation. Scalar perturbations are found to match the latest WMAP-7yrs data within Standard Model Higgs parameters. Primordial gravitational waves also, although propagating with superluminal speed, are consistent with present data. Finally, we estimate the values of the parameter of the New Higgs Inflation in relation to the Higgs mass, the spectral index and amplitude of the primordial scalar perturbations showing that the unitarity bound of the theory is not violated.
Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector
Energy Technology Data Exchange (ETDEWEB)
de Florian, D. [National Univ. of San Martin, Buenos Aires (Argentina); et al.
2016-10-25
This Report summarizes the results of the activities of the LHC Higgs Cross Section Working Group in the period 2014-2016. The main goal of the working group was to present the state-of-the-art of Higgs physics at the LHC, integrating all new results that have appeared in the last few years. The first part compiles the most up-to-date predictions of Higgs boson production cross sections and decay branching ratios, parton distribution functions, and off-shell Higgs boson production and interference effects. The second part discusses the recent progress in Higgs effective field theory predictions, followed by the third part on pseudo-observables, simplified template cross section and fiducial cross section measurements, which give the baseline framework for Higgs boson property measurements. The fourth part deals with the beyond the Standard Model predictions of various benchmark scenarios of Minimal Supersymmetric Standard Model, extended scalar sector, Next-to-Minimal Supersymmetric Standard Model and exotic Higgs boson decays. This report follows three previous working-group reports: Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002), Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002), and Handbook of LHC Higgs Cross Sections: 3. Higgs properties (CERN-2013-004). The current report serves as the baseline reference for Higgs physics in LHC Run 2 and beyond.
Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson ...
Indian Academy of Sciences (India)
The Higgs sector of the MSSM contains two scalar doublet fields leading to five ... At tree level, the masses and couplings of the MSSM Higgs bosons ..... J F Gunion, H E Haber, G Kane and S Dawson, The Higgs Hunters Guide (Addison-.
Signatures of Higgs dilaton and critical Higgs inflation.
García-Bellido, Juan
2018-03-06
We test the Higgs dilaton inflation model (HDM) using the latest cosmological datasets, including the cosmic microwave background temperature, polarization and lensing data from the Planck satellite (2015), the BICEP and Keck Array experiments, the type Ia supernovae from the JLA catalogue, the baryon acoustic oscillations from CMASS, LOWZ and 6dF, the weak lensing data from the CFHTLenS survey and the matter power spectrum measurements from the latest SDSS data release. We find that the values of all cosmological parameters allowed by the HDM are well within the Planck satellite (2015) constraints. In particular, we determine [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] (at 95.5% c.l.). We also place new stringent constraints on the couplings of the HDM, ξ χ Higgs inflation model, taking into account the running of both the self-coupling λ( μ ) and the non-minimal coupling to gravity ξ ( μ ). We find peaks in the curvature power spectrum at scales corresponding to the critical value μ that re-enter during the radiation era and collapse to form a broad distribution of clustered primordial black holes, which could constitute today the main component of dark matter.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).
International Nuclear Information System (INIS)
Brown, N.
1990-01-01
If the standard Higgs particle is very light (≤50 MeV) then it will be sufficiently long lived that it could decay outside the detectors at LEP. This could give a signal of two final state leptons which are not back-to-back, with missing transverse momentum. We show that with suitable cuts this Higgs signal can be distinguished from backgrounds with a large enough rate that such a light Higgs will either be discovered or completely ruled out. (author)
A Brief Survey of Higgs Bundles
Zúñiga-Rojas, Ronald Alberto
2018-01-01
Considering a compact Riemann surface of genus greater than two, a Higgs~bundle is a pair composed of a holomorphic bundle over the Riemann surface, joint with an auxiliar vector field, so-called Higgs field. This theory started around thirty years ago, with Hitchin's work, when he reduced the self-duality equations from dimension four to dimension two, and so, studied those equations over Riemann surfaces. Hitchin baptized those fields as "Higgs fields" beacuse in the context of physics and ...
Stability of infinite derivative Abelian Higgs models
Ghoshal, Anish; Mazumdar, Anupam; Okada, Nobuchika; Villalba, Desmond
2018-04-01
Motivated by the stringy effects by modifying the local kinetic term of an Abelian Higgs field by the Gaussian kinetic term, we show that the Higgs field does not possess any instability; the Yukawa coupling between the scalar and the fermion, the gauge coupling, and the self interaction of the Higgs yields exponentially suppressed running at high energies, showing that such class of theory never suffers from vacuum instability. We briefly discuss its implications for the early Universe cosmology.
Improved formalism for precision Higgs coupling fits
Barklow, Tim; Fujii, Keisuke; Jung, Sunghoon; Karl, Robert; List, Jenny; Ogawa, Tomohisa; Peskin, Michael E.; Tian, Junping
2018-03-01
Future e+e- colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e+e- data, based on the effective field theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e+e- colliders.
Improved formalism for precision Higgs coupling fits
International Nuclear Information System (INIS)
Barklow, Tim; Peskin, Michael E.; Jung, Sunghoon; Tian, Junping
2017-08-01
Future e + e - colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e + e - data, based on the Effective Field Theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e + e - colliders.
Cohen, Timothy; Giudice, Gian F.; Mccullough, Matthew
2018-05-15
We introduce the Hyperbolic Higgs, a novel solution to the little hierarchy problem that features Standard Model neutral scalar top partners. At one-loop order, the protection from ultraviolet sensitivity is due to an accidental non-compact symmetry of the Higgs potential that emerges in the infrared. Once the general features of the effective description are detailed, a completion that relies on a five dimensional supersymmetric framework is provided. Novel phenomenology is compared and contrasted with the Twin Higgs scenario.
Spontaneous parity violation and minimal Higgs models
International Nuclear Information System (INIS)
Chavez, H.; Martins Simoes, J.A.
2007-01-01
In this paper we present a model for the spontaneous breaking of parity with two Higgs doublets and two neutral Higgs singlets which are even and odd under D-parity. The condition υ R >>υ L can be satisfied without introducing bidoublets, and it is induced by the breaking of D-parity through the vacuum expectation value of the odd Higgs singlet. Examples of left-right symmetric and mirror fermions models in grand unified theories are presented. (orig.)
Higgs Mass Textures in Flipped SU(5)
Ellis, Jonathan Richard; Rizos, J; Ellis, John
1999-01-01
We analyze the Higgs doublet-triplet mass splitting problem in the version of flipped SU(5) derived from string theory. Analyzing non-renormalizable terms up to tenth order in the superpotential, we identify a pattern of field vev's that keeps one pair of electroweak Higgs doublets light, while all other Higgs doublets and all Higgs triplets are kept heavy, with the aid of the economical missing-doublet mechanism found in the field-theoretical version of flipped SU(5). The solution predicts that second-generation charge -1/3 quarks and charged leptons are much lighter than those in the third generation.
Higgs decays and brane gravi-vectors
International Nuclear Information System (INIS)
Clark, T. E.; Liu Boyang; Love, S. T.; Xiong, C.; Veldhuis, T. ter
2008-01-01
Higgs boson decays in flexible brane world models with stable, massive gravi-vectors are considered. Such vectors couple bilinearly to the standard model fields through either the standard model energy-momentum tensor, the weak hypercharge field strength, or the Higgs scalar. The role of the coupling involving the extrinsic curvature is highlighted. It is found that within the presently allowed parameter space, the decay rate of the Higgs into two gravi-vectors (which would appear as an invisible Higgs decay) can be comparable to the rate for any of the standard model decay modes.
Higgs Particle: The Origin of Mass
Okada, Yasuhiro
2007-11-01
The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments, LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics.
Higgs particle. The origin of mass
International Nuclear Information System (INIS)
Okada, Yasuhiro
2007-01-01
The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments. LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics. (author)
Rayan, Steven
2010-01-01
Co-Higgs bundles are Higgs bundles in the sense of Simpson, but with Higgs fields that take values in the tangent bundle instead of the cotangent bundle. Given a vector bundle on P^1, we find necessary and sufficient conditions on its Grothendieck splitting for it to admit a stable Higgs field. We characterize the rank-2, odd-degree moduli space as a universal elliptic curve with a globally-defined equation. For ranks r=2,3,4, we explicitly verify the conjectural Betti numbers emerging from t...
New Physics and novel Higgs signals
International Nuclear Information System (INIS)
Diaz-Cruz, J. Lorenzo
2003-01-01
We review some of the results of our recent work dealing with the novel type of Higgs signals that arise when one considers extensions of the standard model. We discuss first possible deviations on the Higgs couplings due to heavy particles, in the context of the MSSM and with large extra-dimensions. Then, we present several models where it is possible to induce flavor violating Higgs couplings, and probe them at future hadron colliders through the LFV Higgs decay h → τμ or with rare top decays
Strongly interacting Higgs sector without technicolor
International Nuclear Information System (INIS)
Liu Chuan; Kuti, J.
1994-12-01
Simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with a higher derviative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection. As a finite and unitary theory in the continuum, this model serves as an explicit and simple example of a strong interacting Higgs sector without technicolor. (orig.)
The hunt for the Higgs particle
CERN. Geneva
2007-01-01
With the advent of the LHC, the hunt for the Higgs boson enters its crucial phase. These three lectures will review: the Higgs mechanism; its implementation in the minimal Standard Model; possible alternatives with and without elementary scalar fields; the presently available information on electroweak gauge symmetry breaking and the Higgs particle; the properties of the Higgs boson(s) in the Standard Model and its supersymmetric extensions; the strategies for direct searches at colliders, with emphasis on the LHC, and comments on the possible scenarios that may emerge.
Light Higgs bosons in phenomenological NMSSM
Energy Technology Data Exchange (ETDEWEB)
Mahmoudi, F. [CERN, Geneva (Switzerland); Clermont Univ., CNRS/IN2P3, LPC, Clermont-Ferrand (France); Rathsman, J. [Uppsala Univ. (Sweden). High-Energy Physics; Lund Univ. (Sweden). Theoretical High Energy Physics; Staal, O. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zeune, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Goettingen Univ. (Germany). II. Physikalisches Inst.
2010-12-15
We consider scenarios in the next-to-minimal supersymmetric model (NMSSM) where the CP-odd and charged Higgs bosons are very light. As we demonstrate, these can be obtained as simple deformations of existing phenomenological MSSM benchmarks scenarios with parameters defined at the weak scale. This offers a direct and meaningful comparison to the MSSM case. Applying a wide set of up-to-date constraints from both high-energy collider and flavour physics, the Higgs boson masses and couplings are studied in viable parts of parameter space. The LHC phenomenology of the light Higgs scenario for neutral and charged Higgs boson searches is discussed. (orig.)
Light Higgs bosons in phenomenological NMSSM
International Nuclear Information System (INIS)
Mahmoudi, F.; Rathsman, J.; Zeune, L.; Goettingen Univ.
2010-12-01
We consider scenarios in the next-to-minimal supersymmetric model (NMSSM) where the CP-odd and charged Higgs bosons are very light. As we demonstrate, these can be obtained as simple deformations of existing phenomenological MSSM benchmarks scenarios with parameters defined at the weak scale. This offers a direct and meaningful comparison to the MSSM case. Applying a wide set of up-to-date constraints from both high-energy collider and flavour physics, the Higgs boson masses and couplings are studied in viable parts of parameter space. The LHC phenomenology of the light Higgs scenario for neutral and charged Higgs boson searches is discussed. (orig.)
Electroweak symmetry breaking: Higgs/whatever
International Nuclear Information System (INIS)
Chanowitz, M.S.
1990-01-01
In these two lectures the author discusses electroweak symmetry breaking from a general perspective, stressing properties that are model independent and follow just from the assumption that the electroweak interactions are described by a spontaneously broken gauge theory. This means he assumes the Higgs mechanism though not necessarily the existence of Higgs bosons. The first lecture presents the general framework of a spontaneously broken gauge theory: (1) the Higgs mechanism sui generis, with or without Higgs boson(s) and (2) the implications of symmetry and unitarity for the mass scale and interaction strength of the new physics that the Higgs mechanism requires. In addition he reviews a softer theoretical argument based on the naturalness problem which leads to a prejudice against Higgs bosons unless they are supersymmetric. This is a prejudice, not a theorem, and it could be overturned in the future by a clever new idea. In the second lecture he illustrates the general framework by reviewing some specific models: (1) the Weinberg-Salam model of the Higgs sector; (2) the minimal supersymmetric extension of the Weinberg-Salam model; and (3) technicolor as an example of the Higgs mechanism without Higgs bosons. He concludes the second lecture with a discussion of strong WW scattering that must occur if L SB lives above 1 TeV. In particular he describes some of the experimental signals and backgrounds at the SSC. 57 refs., 12 figs
Numerical simulation of Higgs models
International Nuclear Information System (INIS)
Jaster, A.
1995-10-01
The SU(2) Higgs and the Schwinger model on the lattice were analysed. Numerical simulations of the SU(2) Higgs model were performed to study the finite temperature electroweak phase transition. With the help of the multicanonical method the distribution of an order parameter at the phase transition point was measured. This was used to obtain the order of the phase transition and the value of the interface tension with the histogram method. Numerical simulations were also performed at zero temperature to perform renormalization. The measured values for the Wilson loops were used to determine the static potential and from this the renormalized gauge coupling. The Schwinger model was simulated at different gauge couplings to analyse the properties of the Kaplan-Shamir fermions. The prediction that the mass parameter gets only multiplicative renormalization was tested and verified. (orig.)
Sharma, Vivek
2016-01-01
The recent observation of the Higgs boson has been hailed as the scientific discovery of the century and led to the 2013 Nobel Prize in physics. This book describes the detailed science behind the decades-long search for this elusive particle at the Large Electron Positron Collider at CERN and at the Tevatron at Fermilab and its subsequent discovery and characterization at the Large Hadron Collider at CERN. Written by physicists who played leading roles in this epic search and discovery, this book is an authoritative and pedagogical exposition of the portrait of the Higgs boson that has emerged from a large number of experimental measurements. As the first of its kind, this book should be of interest to graduate students and researchers in particle physics.
Energy Technology Data Exchange (ETDEWEB)
NONE
1999-06-15
Physical protection against the theft or unauthorized diversion of nuclear materials and against the sabotage of nuclear facilities by individuals or groups has long been a matter of national and international concern. Although responsibility for establishing and operating a comprehensive physical protection system for nuclear materials and facilities within a State rests entirely with the Government of that State, it is not a matter of indifference to other States whether and to what extent that responsibility is fulfilled. Physical protection has therefore become a matter of international concern and co-operation. The need for international co-operation becomes evident in situations where the effectiveness of physical protection in one State depends on the taking by other States also of adequate measures to deter or defeat hostile actions against nuclear facilities and nuclear materials, particularly when such materials are transported across national frontiers [Spanish] La proteccion fisica contra el robo o la desviacion no autorizada de materiales nucleares y contra el sabotaje de las instalaciones nucleares por parte de individuos o grupos es motivo de preocupacion nacional e internacional desde hace mucho tiempo. Aunque la obligacion de crear y hacer funcionar un sistema completo de proteccion fisica de las instalaciones y materiales nucleares en el territorio de un Estado determinado incumbe exclusivamente al Gobierno de dicho Estado, el que esa obligacion se cumpla o no, y si se cumple, en que medida o hasta que punto, son cosas que no dejan indiferentes a los demas Estados. Por ello, la proteccion fisica se ha convertido en motivo de interes y cooperacion internacional. La necesidad de la cooperacion internacional se hace evidente en los casos en que la eficacia de la proteccion fisica en el territorio de un Estado depende de que otros Estados tomen tambien medidas apropiadas para evitar o hacer fracasar los actos hostiles dirigidos contra instalaciones y
LHCb Exotica and Higgs searches
Lucchesi, Donatella
2016-01-01
The unique phase space coverage and features of the LHCb detector at the LHC makes it an ideal environment to probe complementary New Physics parameter regions. In particular, recently developed jet tagging algorithms are ideal for searches involving $b$ and $c$ jets. This poster will review different jet-related exotica searches together with the efforts in the search for a Higgs boson decaying to a pair of heavy quarks.
Inflation and the Higgs Scalar
Energy Technology Data Exchange (ETDEWEB)
Green, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2014-12-05
This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A simple scalar model of inflation is evaluated which provides the solution of those problems and makes predictions which will soon be definitively tested. The possibility that the recently discovered fundamental Higgs scalar field drives inflation is explored.
Barbieri, Riccardo; Kannike, Kristjan; Sala, Filippo; Tesi, Andrea
2013-01-01
Now that one has been found, the search for signs of more scalars is a primary task of current and future experiments. In the motivated hypothesis that the extra Higgs bosons of the next-to-minimal supersymmetric Standard Model (NMSSM) be the lightest new particles around, we outline a possible overall strategy to search for signs of the CP-even states. This work complements Ref. arXiv:1304.3670.
Number theory meets Higgs physics
CERN. Geneva
2014-01-01
Inspired by results from modern number theory and algebraic geometry, a lot of progress has recently been made regarding the computation of multi-loop integrals and scattering amplitudes. I will discuss various new approaches to the computation of loop integrals, and illustrate them on the first computation of a quantity at N3LO in perturbative QCD, the soft-virtual part of the inclusive Higgs-boson cross section in gluon fusion at N3LO.
Exploring holographic Composite Higgs models
Energy Technology Data Exchange (ETDEWEB)
Croon, Djuna [Department of Physics and Astronomy, University of Sussex,BN1 9QH Brighton (United Kingdom); Perimeter Institute for Theoretical Physics,Waterloo, ON (Canada); Dillon, Barry M.; Huber, Stephan J.; Sanz, Veronica [Department of Physics and Astronomy, University of Sussex,BN1 9QH Brighton (United Kingdom)
2016-07-13
Simple Composite Higgs models predict new vector-like fermions not too far from the electroweak scale, yet LHC limits are now sensitive to the TeV scale. Motivated by this tension, we explore the holographic dual of the minimal model, MCHM{sub 5}, to try and alleviate this tension without increasing the fine-tuning in the Higgs potential. Interestingly, we find that lowering the UV cutoff in the 5D picture allows for heavier top partners and less fine-tuning. In the 4D dual this corresponds to increasing the number of “colours” N, thus increasing the decay constant of the Goldstone Higgs. This is essentially a ‘Little Randall-Sundrum Model’, which are known to reduce some flavour and electroweak constraints. Furthermore, in anticipation of the ongoing efforts at the LHC to put bounds on the top Yukawa, we demonstrate that deviations from the SM can be suppressed or enhanced with respect to what is expected from mere symmetry arguments in 4D. We conclude that the 5D holographic realisation of the MCHM{sub 5} with a small UV cutoff is not in tension with the current experimental data.
Espinosa, J.R.; Muhlleitner, M.; Trott, M.
2012-01-01
The 8 TeV LHC Higgs search data just released indicates the existence of a scalar resonance with mass ~ 125 GeV. We examine the implications of the data reported by ATLAS, CMS and the Tevatron collaborations on understanding the properties of this scalar by performing joint fits on its couplings to other Standard Model particles. We discuss and characterize to what degree this resonance has the properties of the Standard Model (SM) Higgs, and consider what implications can be extracted for New Physics in a (mostly) model-independent fashion. We find that, if the Higgs couplings to fermions and weak vector bosons are allowed to differ from their standard values, the SM is ~ 2 sigma from the best fit point to current data. Fitting to a possible invisible decay branching ratio, we find BR_{inv} = 0.05\\pm 0.32\\ (95% C.L.) We also discuss and develop some ways of using the data in order to bound or rule out models which modify significantly the properties of this scalar resonance and apply these techniques to the ...
2008-01-01
Like his eponymous particle, Peter Higgs can be elusive. However, for the momentous occasion of the Open Days there was a chance, if you were lucky, to catch a glimpse of him. Peter Higgs marvels at the enormity of the ATLAS experiment. Taking a closer look at CMS.Visiting CERN for the first time in more than 20 years, Peter Higgs has become something of a celebrity in the world of particle physics. During his visit he showed genuine amazement at the sight of the LHC and its experiments. On seeing CMS he said, "It’s very impressive, very dramatic. I’d seen pictures of course, but they can’t compare." Surrounded for most of his stay by an entourage of physicists, the notoriously modest scientist laughs at the almost mythical quality his boson has taken on. For him though, it is just one of many aspects of physics that the CMS and ATLAS experiments can shine a light on. Besides finding ...
Difficult scenarios for NMSSM Higgs discovery at the LHC
International Nuclear Information System (INIS)
Ellwanger, Ulrich; Gunion, John F.; Hugonie, Cyril
2005-01-01
We identify scenarios not ruled out by LEP data in which NMSSM Higgs detection at the LHC will be particularly challenging. We first review the 'no-lose' theorem for Higgs discovery at the LHC that applies if Higgs bosons do not decay to other Higgs bosons - namely, with L = 300 fb -1 , there is always one or more 'standard' Higgs detection channel with at least a 5σ signal. However, we provide examples of no-Higgs-to-Higgs cases for which all the standard signals are no larger than 7σ implying that if the available L is smaller or the simulations performed by ATLAS and CMS turn out to be overly optimistic, all standard Higgs signals could fall below 5σ even in the no-Higgs-to-Higgs part of NMSSM parameter space. In the vast bulk of NMSSM parameter space, there will be Higgs-to-Higgs decays. We show that when such decays are present it is possible for all the standard detection channels to have very small significance. In most such cases, the only strongly produced Higgs boson is one with fairly SM-like couplings that decays to two lighter Higgs bosons (either a pair of the lightest CP-even Higgs bosons, or, in the largest part of parameter space, a pair of the lightest CP-odd Higgs bosons). A number of representative bench-mark scenarios of this type are delineated in detail and implications for Higgs discovery at various colliders are discussed
Higgs inflation and the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Jegerlehner, Fred [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2014-02-15
The Higgs not only induces the masses of all SM particles, the Higgs, given its special mass value, is the natural candidate for the inflaton and in fact is ruling the evolution of the early universe, by providing the necessary dark energy which remains the dominant energy density. SM running couplings not only allow us to extrapolate SM physics up to the Planck scale, but equally important they are triggering the Higgs mechanism. This is possible by the fact that the bare mass term in the Higgs potential changes sign at about μ{sub 0}≅1.40 x 10{sup 16} GeV and in the symmetric phase is enhanced by quadratic terms in the Planck mass. Such a huge Higgs mass term is able to play a key role in triggering inflation in the early universe. In this article we extend our previous investigation by working out the details of a Higgs inflation scenario. We show how different terms contributing to the Higgs Lagrangian are affecting inflation. Given the SM and its extrapolation to scales μ>μ{sub 0} we find a calculable cosmological constant V(0) which is weakly scale dependent and actually remains large during inflation. This is different to the Higgs fluctuation field dependent ΔV(φ), which decays exponentially during inflation, and actually would not provide a sufficient amount of inflation. The fluctuation field has a different effective mass which shifts the bare Higgs transition point to a lower value μ'{sub 0} ≅7.7 x 10{sup 14} GeV. The vacuum energy V(0) being proportional to M{sub Pl}{sup 4} has a coefficient which vanishes near the Higgs transition point, such that the bare and the renormalized cosmological constant match at this point. The role of the Higgs in reheating and baryogenesis is emphasized.
Status of the charged Higgs boson in two Higgs doublet models
Arbey, A.; Mahmoudi, F.; Stål, O.; Stefaniak, T.
2018-03-01
The existence of charged Higgs boson(s) is inevitable in models with two (or more) Higgs doublets. Hence, their discovery would constitute unambiguous evidence for new physics beyond the Standard Model (SM). Taking into account all relevant results from direct charged and neutral Higgs boson searches at LEP and the LHC, as well as the most recent constraints from flavour physics, we present a detailed analysis of the current phenomenological status of the charged Higgs sector in a variety of well-motivated two Higgs doublet models (2HDMs). We find that charged Higgs bosons as light as 75 GeV can still be compatible with the combined data, although this implies severely suppressed charged Higgs couplings to all fermions. In more popular models, e.g. the 2HDM of Type II, we find that flavour physics observables impose a combined lower limit on the charged Higgs mass of M_{H^± } ≳ 600 GeV - independent of tan β - which increases to M_{H^± } ≳ 650 GeV for tan β < 1. We furthermore find that in certain scenarios, the signature of a charged Higgs boson decaying into a lighter neutral Higgs boson and a W boson provides a promising experimental avenue that would greatly complement the existing LHC search programme for charged Higgs boson(s).
Trilinear Higgs couplings in the two Higgs doublet model with CP violation
International Nuclear Information System (INIS)
Osland, Per; Pandita, P. N.; Selbuz, Levent
2008-01-01
We carry out a detailed analysis of the general two Higgs doublet model with CP violation. We describe two different parametrizations of this model, and then study the Higgs boson masses and the trilinear Higgs couplings for these two parametrizations. Within a rather general model, we find that the trilinear Higgs couplings have a significant dependence on the details of the model, even when the lightest Higgs boson mass is taken to be a fixed parameter. We include radiative corrections in the one-loop effective potential approximation in our analysis of the Higgs boson masses and the Higgs trilinear couplings. The one-loop corrections to the trilinear couplings of the two Higgs doublet model also depend significantly on the details of the model, and can be rather large. We study quantitatively the trilinear Higgs couplings, and show that these couplings are typically several times larger than the corresponding standard model trilinear Higgs coupling in some regions of the parameter space. We also briefly discuss the decoupling limit of the two Higgs doublet model.
Status of the charged Higgs boson in two Higgs doublet models
International Nuclear Information System (INIS)
Arbey, A.; Mahmoudi, F.; Stefaniak, T.; Staal, O.
2018-01-01
The existence of charged Higgs boson(s) is inevitable in models with two (or more) Higgs doublets. Hence, their discovery would constitute unambiguous evidence for new physics beyond the Standard Model (SM). Taking into account all relevant results from direct charged and neutral Higgs boson searches at LEP and the LHC, as well as the most recent constraints from flavour physics, we present a detailed analysis of the current phenomenological status of the charged Higgs sector in a variety of well-motivated two Higgs doublet models (2HDMs). We find that charged Higgs bosons as light as 75 GeV can still be compatible with the combined data, although this implies severely suppressed charged Higgs couplings to all fermions. In more popular models, e.g. the 2HDM of Type II, we find that flavour physics observables impose a combined lower limit on the charged Higgs mass of M H ± > or similar 600 GeV - independent of tan β - which increases to M H ± > or similar 650 GeV for tan β < 1. We furthermore find that in certain scenarios, the signature of a charged Higgs boson decaying into a lighter neutral Higgs boson and a W boson provides a promising experimental avenue that would greatly complement the existing LHC search programme for charged Higgs boson(s). (orig.)
Recent developments in HiggsBounds and a preview of HiggsSignals
Energy Technology Data Exchange (ETDEWEB)
Bechtle, Philip; Stefaniak, Tim; Williams, Karina [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). Dept. of Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver
2013-01-15
We report on recent developments in the public computer code HiggsBounds, which confronts arbitrary Higgs sector predictions with 95% C.L. exclusion limits from Higgs searches at the LEP, Tevatron and LHC experiments. We discuss in detail the performance of the Standard Model (SM) likeness test as implemented in the latest version HiggsBounds-3.8.0, whose outcome decides whether a search for a SM Higgs boson can be applied to a model beyond the SM. Furthermore, we give a preview of features in the upcoming version HiggsBounds-4.0.0 and the new program HiggsSignals, which performs a {chi}{sup 2} test of Higgs sector predictions against the signal rate and mass measurements from Higgs boson analyses at the Tevatron and LHC. This is illustrated with an example where the heavier CP-even Higgs boson of the Minimal Supersymmetric Standard Model (MSSM) is considered as an explanation of the LHC Higgs signal at {approx_equal} 126 GeV.
Neutral Supersymmetric Higgs Boson Searches
Energy Technology Data Exchange (ETDEWEB)
Robinson, Stephen Luke [Imperial College, London (United Kingdom)
2008-07-01
In some Supersymmetric extensions of the Standard Model, including the Minimal Supersymmetric Standard Model (MSSM), the coupling of Higgs bosons to b-quarks is enhanced. This enhancement makes the associated production of the Higgs with b-quarks an interesting search channel for the Higgs and Supersymmetry at D0. The identification of b-quarks, both online and offline, is essential to this search effort. This thesis describes the author's involvement in the development of both types of b-tagging and in the application of these techniques to the MSSM Higgs search. Work was carried out on the Level-3 trigger b-tagging algorithms. The impact parameter (IP) b-tagger was retuned and the effects of increased instantaneous luminosity on the tagger were studied. An extension of the IP-tagger to use the z-tracking information was developed. A new b-tagger using secondary vertices was developed and commissioned. A tool was developed to allow the use of large multi-run samples for trigger studies involving b-quarks. Offline, a neural network (NN) b-tagger was trained combining the existing offline lifetime based b-tagging tools. The efficiency and fake rate of the NN b-tagger were measured in data and MC. This b-tagger was internally reviewed and certified by the Collaboration and now provides the official b-tagging for all analyses using the Run IIa dataset at D0. A search was performed for neutral MSSM Higgs bosons decaying to a b{bar b} pair and produced in association with one or more b-quarks. Limits are set on the cross-section times the branching ratio for such a process. The limits were interpreted in various MSSM scenarios. This analysis uses the NN b-tagger and was the first to use this tool. The analysis also relies on triggers using the Level-3 IP b-tagging tool described previously. A likelihood discriminant was used to improve the analysis and a neural network was developed to cross-check this technique. The result of the analysis has been submitted to PRL
Can we distinguish an MSSM Higgs from a SM Higgs at a linear collider?
International Nuclear Information System (INIS)
Logan, Heather E.
2001-01-01
We study the prospects for distinguishing the CP-even Higgs boson of the minimal supersymmetric extension of the Standard Model (MSSM) from the Standard Model (SM) Higgs boson by measuring its branching ratios at an e + e - linear collider. The regions of the M A -tan β plane in which an MSSM Higgs boson can be distinguished from the SM Higgs boson depend strongly upon the supersymmetric parameters that enter the radiative corrections to the Higgs mass matrix and the Higgs couplings to fermions. In some regions of parameter space it is possible to extract the supersymmetric correction to the relation between the b quark mass and its Yukawa coupling from Higgs branching ratio measurements
Can the 125 GeV Higgs be the Little Higgs?
Energy Technology Data Exchange (ETDEWEB)
Reuter, J.; Tonini, M
2012-12-15
After the discovery of the Higgs-like boson by the LHC 2012 it is the most important task to check whether this new particle is the Standard Model Higgs boson or something else. In this paper, we study whether the 125 GeV boson could be the pseudo- Goldstone boson of Little Higgs models. We derive limits on the parameter space of several Little Higgs models (simple group and product group models, with and without T-parity), both from the experimental data from ATLAS and CMS about the different Higgs discovery channel and the electroweak precision observables. We perform a fit of several Little Higgs models to all electroweak parameters from measurements of SLC, LEP, Tevatron, and LHC. For the Higgs searches, we include all available data from the summer conferences 2012 as well as the update from December 2012.
Analisi del decadimento $W -> \\tau \
Coscetti, Simone
Questo lavoro di tesi si e' svolto nell'ambito dell'esperimento CMS a LHC, ed in particolare verte sullo studio delle strategie di identificazione off-line del leptone tau, atteso tra i prodotti di decadimento del bosone di Higgs, cosi' come di altre particelle previste in altri modelli teorici. Il canale utilizzato per testare la procedura di identificazione del tau e' il decadimento semileptonico del bosone vettore W. Infine, sulla base dei risultati ottenuti viene presentata una stima quantitativa della sezione d'urto di produzione pp-> W + X
The Vortex Oscillations and Abelian Higgs Model
International Nuclear Information System (INIS)
Karkowski, J.; Swierczynski, Z.
2000-01-01
The excitations of the vortex in Abelian Higgs model with small ratio of vector and Higgs particle masses are considered. Three main modes encountered in numerical computations are described in detail. They are also compared to analytic results obtained recently by Arodz and Hadasz in Phys. Rev. D54, 4004 (1996). (author)
A Philosophical Look at the Higgs Mechanism
Friederich, Simon
2014-01-01
On the occasion of the recent experimental detection of a Higgs-type particle at the Large Hadron Collider at CERN, the paper reviews philosophical aspects of the Higgs mechanism as the presently preferred account of the generation of particle masses in the Standard Model of elementary particle
Bounding the Higgs boson width through interferometry.
Dixon, Lance J; Li, Ye
2013-09-13
We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.
Composite Higgs Dynamics on the Lattice
DEFF Research Database (Denmark)
Pica, Claudio; Drach, Vincent; Hansen, Martin Rasmus Lundquist
2017-01-01
from composite (Goldstone) Higgs models to intriguing types of dark matter candidates, such as the SIMPs. Here we will focus on the composite Goldstone Higgs paradigm, for which this model provides a minimal UV complete realization in terms of a new strong sector with fermionic matter. After...
Higgs and SUSY searches at future colliders
Indian Academy of Sciences (India)
... searches at future colliders, particularly comparing and contrasting the capabilities of LHC and next linear collider (NLC), including the aspects of Higgs searches in supersymmetric theories. I will also discuss how the search and study of sparticles other than the Higgs can be used to give information about the parameters ...
Baryogenesis via Elementary Goldstone Higgs Relaxation
DEFF Research Database (Denmark)
Gertov, Helene; Pearce, Lauren; Sannino, Francesco
2016-01-01
We extend the relaxation mechanism to the Elementary Goldstone Higgs framework. Besides studying the allowed parameter space of the theory we add the minimal ingredients needed for the framework to be phenomenologically viable. The very nature of the extended Higgs sector allows to consider very ...... but radiatively generated, it is possible to generate the observed matter-antimatter asymmetry via the relaxation mechanism....
Signatures of Higgs dilaton and critical Higgs inflation
García-Bellido, Juan
2018-01-01
We test the Higgs dilaton inflation model (HDM) using the latest cosmological datasets, including the cosmic microwave background temperature, polarization and lensing data from the Planck satellite (2015), the BICEP and Keck Array experiments, the type Ia supernovae from the JLA catalogue, the baryon acoustic oscillations from CMASS, LOWZ and 6dF, the weak lensing data from the CFHTLenS survey and the matter power spectrum measurements from the latest SDSS data release. We find that the values of all cosmological parameters allowed by the HDM are well within the Planck satellite (2015) constraints. In particular, we determine , , , and (at 95.5% c.l.). We also place new stringent constraints on the couplings of the HDM, ξχ (at 95.5% c.l.). We find that the HDM is only slightly better than the w0waCDM model, with . Given that the HDM has two fewer parameters, we find Bayesian evidence favouring the HDM over the w0waCDM model. We also study the critical Higgs inflation model, taking into account the running of both the self-coupling λ(μ) and the non-minimal coupling to gravity ξ(μ). We find peaks in the curvature power spectrum at scales corresponding to the critical value μ that re-enter during the radiation era and collapse to form a broad distribution of clustered primordial black holes, which could constitute today the main component of dark matter. This article is part of the Theo Murphy meeting issue `Higgs cosmology'.
Flavor with a light dynamical "Higgs particle"
Alonso, R.; Merlo, L.; Rigolin, S.; Yepes, J.
2013-01-01
The Higgs-fermion couplings are sensitive probes of possible new physics behind a stable light Higgs particle. It is then essential to identify the flavour pattern of those interactions. We consider the case in which a strong dynamics lies behind a light Higgs, and explore the implications within the Minimal Flavour Violation ansatz. The dominant effects on flavour-changing Higgs-fermion couplings stem in this context from operators with mass dimension <6, and we analyze all relevant chiral operators up to that order, including loop-corrections induced by 4-dimensional ones. Bounds on the operator coefficients are derived from a plethora of low-energy flavour transitions, providing a guideline on which flavour-changing Higgs interactions may be open to experimental scrutiny. In particular, the coefficient of a genuinely CP-odd operator is only softly constrained and therefore its impact is potentially interesting.
Minimal composite Higgs models at the LHC
Carena, Marcela; Da Rold, Leandro; Pontón, Eduardo
2014-06-01
We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5) → SO(4) symmetry breaking pattern, assuming the "partial compositeness" paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the coupling, i.e. the 5, 10 and 14. We find a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.
The problem with false vacuum Higgs inflation
International Nuclear Information System (INIS)
Fairbairn, Malcolm; Grothaus, Philipp; Hogan, Robert
2014-01-01
We investigate the possibility of using the only known fundamental scalar, the Higgs, as an inflaton with minimal coupling to gravity. The peculiar appearance of a plateau or a false vacuum in the renormalised effective scalar potential suggests that the Higgs might drive inflation. For the case of a false vacuum we use an additional singlet scalar field, motivated by the strong CP problem, and its coupling to the Higgs to lift the barrier allowing for a graceful exit from inflation by mimicking hybrid inflation. We find that this scenario is incompatible with current measurements of the Higgs mass and the QCD coupling constant and conclude that the Higgs can only be the inflaton in more complicated scenarios
Higgs triplets in the standard model
International Nuclear Information System (INIS)
Gunion, J.F.; Vega, R.; Wudka, J.
1990-01-01
Even though the standard model of the strong and electroweak interactions has proven enormously successful, it need not be the case that a single Higgs-doublet field is responsible for giving masses to the weakly interacting vector bosons and the fermions. In this paper we explore the phenomenology of a Higgs sector for the standard model which contains both doublet and triplet fields [under SU(2) L ]. The resulting Higgs bosons have many exotic features and surprising experimental signatures. Since a critical task of future accelerators will be to either discover or establish the nonexistence of Higgs bosons with mass below the TeV scale, it will be important to keep in mind the alternative possibilities characteristic of this and other nonminimal Higgs sectors
CMS presents new boundary of Higgs width
Katarina Anthony
2014-01-01
At last year's Moriond conference, CERN physicists announced the retirement of the "Higgs-like" particle and the arrival of "boson, Higgs boson". Now, one year later, at the same session in the same conference, physicists are back with more exciting news about the famed particle. This time: the best constraint yet of the Higgs Boson “width”, a parameter that determines the particle’s lifetime. Rencontres de Moriond 2014. As a key indicator for new physics, the Higgs “width” has long been on the LHC "to-do" list. Now less than two years post-discovery, the CMS experiment has gotten the closest yet to pinning it down, constraining the parameter to < 17 MeV with 95% confidence. This result is some two orders of magnitude better than previous limits: stronger evidence that this boson looks like the Standard Model Higgs boson. "It's been exciting to see how wel...
Seeking heavy Higgs bosons through cascade decays
Coleppa, Baradhwaj; Fuks, Benjamin; Poulose, P.; Sahoo, Shibananda
2018-04-01
We investigate the LHC discovery prospects for a heavy Higgs boson decaying into the standard model Higgs boson and additional weak bosons. We consider a generic model-independent new physics configuration where this decay proceeds via a cascade involving other intermediate scalar bosons and focus on an LHC final-state signature comprised either of four b -jets and two charged leptons or of four charged leptons and two b -jets. We design two analyses of the corresponding signals, and demonstrate that a 5 σ discovery at the 14 TeV LHC is possible for various combinations of the parent and daughter Higgs-boson masses. We moreover find that the standard model backgrounds can be sufficiently rejected to guarantee the reconstruction of the parent Higgs boson mass. We apply our analyses to the Type-II two-Higgs-doublet model and identify the regions of the parameter space to which the LHC is sensitive.
Minimal composite Higgs models at the LHC
International Nuclear Information System (INIS)
Carena, Marcela; Rold, Leandro Da; Pontón, Eduardo
2014-01-01
We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5)→SO(4) symmetry breaking pattern, assuming the “partial compositeness" paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the Zb-barb coupling, i.e. the 5, 10 and 14. We find a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.
Character Profile of the Higgs boson
AUTHOR|(INSPIRE)INSPIRE-00386479; Bentvelsen, Stan; Ferrari, Pamela
Elementary particle physics describes and measures the properties of the smallest, most fundamental particles that make up the universe. The Standard Model of elementary particle physics provides a fundamental description of particles, their dynamics and interactions. The particles embedded into the theory are, a priori, massless, while observed particles have mass. In order to explain the origin of the elementary particle masses, the Brout-Englert-Higgs mechanism is introduced. The mechanism introduces the existence of one real scalar field, with the Higgs boson as excitation, however it does not predict its mass. To verify that the Higgs mechanism is the origin of elementary particle masses is one of the main goals of the Large Hadron Collider (LHC) programs at CERN. Higgs physics at the ATLAS detector has reached an exciting new phase of precision measurements, but the analyses are still mostly set up for conducting searches. The research shown in this thesis has provided measurements in the Higgs sector, ...
Higgs versus matter in the heterotic landscape
International Nuclear Information System (INIS)
Buchmueller, W.; Schmidt, J.
2009-01-01
In supersymmetric extensions of the standard model there is no basic difference between Higgs and matter fields, which leads to the well-known problem of potentially large baryon and lepton number violating interactions. Although these unwanted couplings can be forbidden by continuous or discrete global symmetries, a theoretical guiding principle for their choice is missing. We examine this problem for a class of vacua of the heterotic string compactified on an orbifold. As expected, in general there is no difference between Higgs and matter. However, certain vacua happen to possess unbroken matter parity and discrete R-symmetries which single out Higgs fields in the low energy effective field theory. We present a method how to identify maximal vacua in which the perturbative contribution to the μ-term and the expectation value of the superpotential vanish. Two vacua are studied in detail, one with two pairs of Higgs doublets and one with partial gauge-Higgs unification
Search for Charged Higgs Bosons with the ATLAS Detector
Barak, L; The ATLAS collaboration
2014-01-01
Several non-minimal Higgs scenarios, e.g. Two Higgs Doublet Models (2HDM), predict the existence of charged Higgs bosons. This talk describes searches for charged Higgs bosons produced in top quark decays, in association with a top quark, or decaying to a tau lepton and a neutrino using the Run I data collected by the ATLAS detector at the LHC.
Probing the non-minimal Higgs sector at the SSC
International Nuclear Information System (INIS)
Gunion, J.F.; Haber, H.E.; Komamiya, S.; Yamamoto, H.; Barbaro-Galtieri, A.
1987-11-01
Non-minimal Higgs sectors occur in the Standard Model with more than one Higgs doublet, as well as in theories that go beyond the Standard Model. In this report, we discuss how Higgs search strategies must be altered, with respect to the Standard Model approaches, in order to probe the non-minimal Higgs sectors at the SSC
CP violation in supersymmetry, Higgs sector and the large hadron ...
Indian Academy of Sciences (India)
I would then point out some interesting aspects of the phenomenology of a moderately light charged Higgs boson, consistent with the LEP constraints, in this scenario. Decay of such a charged Higgs boson would also allow a probe of a light (≲ 50 GeV), CP-violating (CPV) Higgs boson. Such a light neutral Higgs boson ...
Rare decays of the Higgs boson with the CMS detector
Marini, Andrea Carlo
2018-01-01
The CMS collaboration reports the latest update on the searches of invisible and rare decays of the Higgs boson. The searches for the standard model Higgs boson decaying into two muons, for the standard model Higgs boson decaying into $\\ell\\ell\\gamma$, and for invisible decay of the Higgs boson in the vector boson fusion production channel are presented.
Higgs pair production in the CP-violating two-Higgs-doublet model
Bian, Ligong; Chen, Ning; Jiang, Yun
2017-12-01
The SM-like Higgs pair production is discussed in the framework of the general CP-violating two-Higgs-doublet model, where we find that the CP-violating mixing angles can be related to the Higgs self-couplings. Therefore, the future experimental searches for Higgs boson pairs can be constrained by the improved precision of the electric dipole moment measurements. Based on a series of constraints of the SM-like Higgs boson signal fits, the perturbative unitarity and stability bounds to the Higgs potential, and the most recent LHC searches for heavy Higgs bosons, we suggest a set of benchmark models for the future high-energy collider searches for Higgs pair production. The e+e- colliders operating at s = (500GeV,1 TeV) are capable of measuring the Higgs cubic self-couplings of the benchmark models directly. We also estimate the cross sections of the resonance contributions to the Higgs pair productions for the benchmark models at the future LHC and SppC/FCC-hh runs.
125 GeV Higgs boson mass from 5D gauge-Higgs unification
Carson, Jason; Okada, Nobuchika
2018-03-01
In the context of a simple gauge-Higgs unification (GHU) scenario based on the gauge group SU(3)×U(1)^' in a 5D flat space-time, we investigate the possibility of reproducing the observed Higgs boson mass of around 125 GeV. We introduce bulk fermion multiplets with a bulk mass and a (half-)periodic boundary condition. In our analysis, we adopt a low-energy effective theoretical approach of the GHU scenario, where the running Higgs quartic coupling is required to vanish at the compactification scale. Under this "gauge-Higgs condition," we investigate the renormalization group evolution of the Higgs quartic coupling and find a relation between the bulk mass and the compactification scale so as to reproduce the 125 GeV Higgs boson mass. Through quantum corrections at the one-loop level, the bulk fermions contribute to the Higgs boson production and decay processes and deviate the Higgs boson signal strengths at the Large Hadron Collider experiments from the Standard Model (SM) predictions. Employing the current experimental data that show that the Higgs boson signal strengths for a variety of Higgs decay modes are consistent with the SM predictions, we obtain lower mass bounds on the lightest mode of the bulk fermions to be around 1 TeV.
Corrections to di-Higgs boson production with light stops and modified Higgs couplings
Huang, Peisi; Joglekar, Aniket; Li, Min; Wagner, Carlos E. M.
2018-04-01
The Higgs pair production in gluon fusion is a sensitive probe of beyond-standard model (BSM) phenomena and its detection is a major goal for the LHC and higher energy hadron collider experiments. In this work we reanalyze the possible modifications of the Higgs pair production cross section within low energy supersymmetry models. We show that the supersymmetric contributions to the Higgs pair production cross section are strongly correlated with the ones of the single Higgs production in the gluon fusion channel. Motivated by the analysis of ATLAS and CMS Higgs production data, we show that the scalar superpartners' contributions may lead to significant modification of the di-Higgs production rate and invariant mass distribution with respect to the SM predictions. We also analyze the combined effects on the di-Higgs production rate of a modification of the Higgs trilinear and top-quark Yukawa couplings in the presence of light stops. In particular, we show that due to the destructive interference of the triangle and box amplitude contributions to the di-Higgs production cross section, even a small modification of the top-quark Yukawa coupling can lead to a significant increase of the di-Higgs production rate.
AUTHOR|(CDS)2068901
2016-01-01
In quel preciso momento, un centesimo di miliardesimo di secondo dopo il Big Bang, si è deciso il nostro destino. In un universo in cui materia e antimateria si equivalevano, e che quindi avrebbe potuto, in ogni istante, tornare a essere pura energia, può essere bastata una leggerissima preferenza del bosone di Higgs per la materia anziché per l'antimateria ed ecco che si è prodotto il mondo che abbiamo sotto gli occhi. "Ecco qua il minuscolo difetto, la sottile imperfezione da cui è nato tutto. Un'anomalia che dà origine a un universo che può evolvere per miliardi di anni." Se tutto nasce da lì, dobbiamo capire in ogni dettaglio quel momento cruciale, ricostruirlo fotogramma per fotogramma, al rallentatore e da diverse angolature. Per questo al Cern di Ginevra è stato realizzato Lhc, l'acceleratore di particelle più potente del mondo, il posto più simile al primo istante di vita dell'universo che l'uomo sia stato in grado di costruire. Per questo da anni i migliori fisici del mondo lavorano giorno...
Batendo à porta do céu o bóson de Higgs e como a física modern ilumina o universo
Randall, Lisa
2013-01-01
Nesta obra a autora conduz seu mais novo trabalho, seduzindo o leitor pelas descobertas e teorias mais recentes da fisica, conforme realiza uma apaixonada - e necessaria - defesa da importancia da ciencia em nossas vidas. Na veia de autores como Stephen Hawking, Michio Kaku, Brian Greene e Carl Sagan, Randall explora seculos de conhecimento cientifico para tracar uma rica e esclarecedora historia do nosso Universo - do seu nascimento ate a inevitavel morte. Explica tambem o funcionamento do LHC, o maior acelerador de particulas do mundo, uma estrutura gigantesca construida na Suica que vem ajudando cientistas de todo o mundo a solucionar os misterios da materia e da origem da vida. Num capitulo feito especialmente apos a descoberta do boson de Higgs, a chamada 'particula de Deus', Randall elucida as consequencias deste que e um dos mais importantes avancos da historia da fisica. Valendo-se de uma prosa agil e explicativa, e travando um dialogo com profissionais de diversas areas, como roteiristas de cinema, c...
Heinemeyer, S; Passarino, G; Tanaka, R; Andersen, J R; Artoisenet, P; Bagnaschi, E A; Banfi, A; Becher, T; Bernlochner, F U; Bolognesi, S; Bolzoni, P; Boughezal, R; Buarque, D; Campbell, J; Caola, F; Carena, M; Cascioli, F; Chanon, N; Cheng, T; Choi, S Y; David, A; de Aquino, P; Degrassi, G; Del Re, D; Denner, A; van Deurzen, H; Diglio, S; Di Micco, B; Di Nardo, R; Dittmaier, S; Dührssen, M; Ellis, R K; Ferrera, G; Fidanza, N; Flechl, M; de Florian, D; Forte, S; Frederix, R; Frixione, S; Gangal, S; Gao, Y; Garzelli, M V; Gillberg, D; Govoni, P; Grazzini, M; Greiner, N; Griffiths, J; Gritsan, A V; Grojean, C; Hall, D C; Hays, C; Harlander, R; Hernandez-Pinto, R; Höche, S; Huston, J; Jubb, T; Kadastik, M; Kallweit, S; Kardos, A; Kashif, L; Kauer, N; Kim, H; Klees, R; Krämer, M; Krauss, F; Laureys, A; Laurila, S; Lehti, S; Li, Q; Liebler, S; Liu, X; Logan, E; Luisoni, G; Malberti, M; Maltoni, F; Mawatari, K; Maierhoefer, F; Mantler, H; Martin, S; Mastrolia, P; Mattelaer, O; Mazzitelli, J; Mellado, B; Melnikov, K; Meridiani, P; Miller, D J; Mirabella, E; Moch, S O; Monni, P; Moretti, N; Mück, A; Mühlleitner, M; Musella, P; Nason, P; Neu, C; Neubert, M; Oleari, C; Olsen, J; Ossola, G; Peraro, T; Peters, K; Petriello, F; Piacquadio, G; Potter, C T; Pozzorini, S; Prokofiev, K; Puljak, I; Rauch, M; Rebuzzi, D; Reina, L; Rietkerk, R; Rizzi, A; Rotstein-Habarnau, Y; Salam, G P; Sborlini, G; Schissler, F; Schönherr, M; Schulze, M; Schumacher, M; Siegert, F; Slavich, P; Smillie, J M; Stål, O; von Soden-Fraunhofen, J F; Spira, M; Stewart, I W; Tackmann, F J; Taylor, P T E; Tommasini, D; Thompson, J; Thorne, R S; Torrielli, P; Tramontano, F; Tran, N V; Trócsányi, Z; Ubiali, M; Vazquez Acosta, M; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Wagner, C; Walsh, J R; Wang, J; Weiglein, G; Whitbeck, A; Williams, C; Yu, J; Zanderighi, G; Zanetti, M; Zaro, M; Zerwas, P M; Zhang, C; Zirke, T J E; Zuberi, S
2013-01-01
This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered p...
Searches for Higgs and Higgs-like particles at LHCb
Kucharczyk, Marcin
2014-01-01
A set of results related to the new particles searches in LHCb are reported. Upper limits on the cross section times branching fraction of neutral Higgs bos on decaying into two tau leptons have been set in the model independent search and in the Minimal Su persymmetric Model. Many theo- retical models predict the existence of the Higgs bosons dec aying into heavy long-lived particles. The upper limit on their production cross section has been de termined for several combinations of parameters. A measurement of the cross section for the produ ction of b ̄ b and c ̄ c pairs based on in- clusive final states has been performed in a region of pseudor apidity 2.5 5 GeV of the b hadron candidate, resulting in σ ( b ̄ b ) = 7.7 ± 0.12 (stat) ± 0.84 (syst) and σ ( c ̄ c ) = 104.6 ± 2.7 (stat) ± 11.4 (syst). The forward-central b ̄ b production asymme- try, based on the selection of high p T jet pairs tagged by the presence of a displaced muon with high momentum, has been determined to be A b ̄ b FC = (0...
Searches for Higgs and Higgs-like particles at LHCb
AUTHOR|(SzGeCERN)477437
2013-01-01
A set of results related to the new particles searches in LHCb are reported. Upper limits on the cross section times branching fraction of neutral Higgs boson decaying into two tau leptons have been set in the model independent search and in the Minimal Supersymmetric Model. Many theoretical models predict the existence of the Higgs bosons decaying into heavy long-lived particles. The upper limit on their production cross section has been determined for several combinations of parameters. A measurement of the cross section for the production of $b\\overline{b}$ and $c\\overline{c}$ pairs based on inclusive ﬁnal states has been performed in a region of pseudorapidity 2.5 5 GeV of the $b$ hadron candidate, resulting in $\\sigma$ $(b\\overline{b})$ = $7.7 \\pm 0.12 (stat) \\pm 0.84 (syst)$ and $\\sigma$ $(c\\overline{c})$ = $104.6 \\pm 2.7 (stat) \\pm 11.4 (syst)$. The forward-central $b\\overline{b}$ production asymmetry, based on the selection of high $p_T$ jet pairs tagged by the presence of a displaced muon with hig...
Black holes and Higgs stability
Tetradis, Nikolaos
2016-09-20
We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.
Invisible Higgs and Dark Matter
DEFF Research Database (Denmark)
Heikinheimo, Matti; Tuominen, Kimmo; Virkajärvi, Jussi Tuomas
2012-01-01
We investigate the possibility that a massive weakly interacting fermion simultaneously provides for a dominant component of the dark matter relic density and an invisible decay width of the Higgs boson at the LHC. As a concrete model realizing such dynamics we consider the minimal walking...... technicolor, although our results apply more generally. Taking into account the constraints from the electroweak precision measurements and current direct searches for dark matter particles, we find that such scenario is heavily constrained, and large portions of the parameter space are excluded....
Hunting the hidden standard Higgs
International Nuclear Information System (INIS)
Akhundov, A.A.; Bardin, D.Yu.; Riemann, T.
1985-01-01
In the framework of the standard theory of electroweak interactions the Msub(Z) t(the weak neutral gauge form mass) sin sup(2)THETAsub(W) interdependence with account of radiative corrections is investigated as a function of the Higgs boson mass Msub(H) at fixed m sub(t) (mass of heavy up-type quarn). It is shown that precision measurements of Msub(XZ) and sub sup(2)THETAsub(W) at SLC and LEP will allow one to estimate Msub(H) with an accuracy of about 100 GeV
Toponium Tests Of Top-Quark Higgs Bags
Macpherson, Alick L.; Campbell, Bruce A.
1993-01-01
Recently it has been suggested that top quarks, or very massive fourth generation quarks, might surround themselves with a Higgs "bag" of deformation of the Higgs expectation value from its vacuum magnitude. In this paper we address the question of whether such nonlinear Higgs-top interaction effects are subject to experimental test. We first note that if top quarks were necessarily accompanied by Higgs "bags", then top quark weak decay would involve the sudden disruption of the Higgs "bag", ...
Energy Technology Data Exchange (ETDEWEB)
Lora, F de [Direccion de Plantas Piloto e Industriales, Junta de Energia Nuclear, Madrid (Spain)
1967-06-15
A study was made of a sample of radioactive material from Santa Elena (Jaen) containing 130 ppm U{sub 3}O{sub 8}, 300 ppm ThO{sub 2}, 4.96% ZrO{sub 2} and 14.29% TiO{sub 2}. Over 150 million tons of material were examined. In the light of the studies carried out the material can be defined as a rutilo-zirconiferous quartzite with a double radioactivity source due to the uranium enclosed in the zircon lattice structure and to the presence of monazite. The possibility of brannerite or davidite being present can be discarded. There is likewise no conclusive evidence of the presence of sphene, rutile being the most abundant titanium mineral. The author determined the features of the ore with a view to its physical concentration and applied magnetic and gravimetric separation and the flotation process. The use of oleic acid as collector has permitted good zircon recovery. (author) [Spanish] Se ha estudiado una muestra de material radiactivo procedente de Santa Elena (Jaen) con 130 ppm de U{sub 3}O{sub 8}, 600 ppm de ThO{sub 2}, 4,96% de ZrO{sub 2} y 14,29% de TiO{sub 2}. El material examinado es considerable: mas de 150 millones de toneladas. De acuerdo con los estudios realizados se puede definir como una cuarcita rutilo-circonifera con dos fuentes de radiactividad debidas al uranio englobado en la red del circon y a la presencia de monacita. Se descarta la posibilidad de existencia de brannerita o davidita. Tampoco existen pruebas concluyentes de que contenga esfena, siendo el ratilo el mineral de titanio mas abundante. Se han determinado las caracteristicas de la mena con vistas a su concentracion fisica. Se ha ensayado la separacion magnetica, gravimetrica y flotacion. El empleo de acido oleico, como colector, ha dado buenas recuperaciones de circon. (author)
Who will catch the Higgs boson?
International Nuclear Information System (INIS)
Colas, P.; Tuchming, B.
2004-01-01
The Higgs boson was theoretically created about 40 years ago by a Scott Peter Higgs who wanted to explain why some particles get a mass. Since then the Higgs boson has taken consistency and has become an important point of the standard model theory. Its experimental discovery would be a milestone of modern physics. The search for the Higgs boson is an international challenge that takes place around 2 huge machines: the Tevatron near Chicago and the LHC (large hadron collider) that is being built in CERN. The Tevatron is in fact the upgrading of an old particle accelerator, it is a proton collider and its narrow range of energy is compensated by a low background noise. On the other hand the LHC will begin operating only in 2007 and its full power will be reached a few years later, the energy available to create particles will be then 7 times higher than for the Tevatron. Both machines have chance of succeeding by being the first to detect the Higgs boson. Time plays in favor of the Tevatron but in any case if the Higgs boson exists it will be detected at LHC because this equipment covers completely the energy range in which the Higgs boson is suspected to exist. (A.C.)
Higgs Production in a Warped Extra Dimension
Energy Technology Data Exchange (ETDEWEB)
Carena, Marcela [Chicago U., EFI; Casagrande, Sandro [Munich, Tech. U., Universe; Goertz, Florian [Zurich, ETH; Haisch, Ulrich [Oxford U., Theor. Phys.; Neubert, Matthias [Mainz U., Inst. Phys.
2012-04-01
Measurements of the Higgs-boson production cross section at the LHC are an important tool for studying electroweak symmetry breaking at the quantum level, since the main production mechanism gg-->h is loop-suppressed in the Standard Model (SM). Higgs production in extra-dimensional extensions of the SM is sensitive to the Kaluza-Klein (KK) excitations of the quarks, which can be exchanged as virtual particles in the loop. In the context of the minimal Randall-Sundrum (RS) model with bulk fields and a brane-localized Higgs sector, we derive closed analytical expressions for the gluon-gluon fusion process, finding that the effect of the infinite tower of virtual KK states can be described in terms of a simple function of the fundamental (5D) Yukawa matrices. Given a specific RS model, this will allow one to easily constrain the parameter space, once a Higgs signal has been established. We explain that discrepancies between existing calculations of Higgs production in RS models are related to the non-commutativity of two limits: taking the number of KK states to infinity and removing the regulator on the Higgs-boson profile, which is required in an intermediate step to make the relevant overlap integrals well defined. Even though the one-loop gg-->h amplitude is finite in RS scenarios with a brane-localized Higgs sector, it is important to introduce a consistent ultraviolet regulator in order to obtain the correct result.
A theoretical limit on the Higgs mass
International Nuclear Information System (INIS)
Temiraliev, A.T.
2007-01-01
Full text: The standard model of particle physics, which describes masses through the Higgs mechanism, contains parameters - such as particle masses - whose origins are still unknown and which cannot be exactly predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark and W boson constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. Several more or less precise arguments can set the upper limit for a standard model Higgs particle. All of them follows the line that the standard model breaks down of the Higgs mass is pushed too far upwards. The theoretical bounds will be reviewed. With gauge-top quark Yukawa coupling unification the standard model Higgs boson mass is estimated to be about 135 GeV. In the article will be consider an approximation of 4-fermion interactions. And as a result, the most likely Higgs mass is 150 GeV. The upper limit on the Higgs mass at the 90 % confidence level is about 250 GeV
NMSSM interpretations of the observed Higgs signal
International Nuclear Information System (INIS)
Domingo, Florian; Weiglein, Georg
2015-01-01
While the properties of the signal that was discovered in the Higgs searches at the LHC are consistent so far with the Higgs boson of the Standard Model (SM), it is crucial to investigate to what extent other interpretations that may correspond to very different underlying physics are compatible with the current results. We use the Next-to-Minimal Supersymmetric Standard Model (NMSSM) as a well-motivated theoretical framework with a sufficiently rich Higgs phenomenology to address this question, making use of the public tools HiggsBounds and HiggsSignals in order to take into account comprehensive experimental information on both the observed signal and on the existing limits from Higgs searches at LEP, the TeVatron and the LHC. We find that besides the decoupling limit resulting in a single light state with SM-like properties, several other configurations involving states lighter or quasi-degenerate with the one at about 125 GeV turn out to give a competitive fit to the Higgs data and other existing constraints. We discuss the phenomenology and possible future experimental tests of those scenarios, and compare the features of specific scenarios chosen as examples with those arising from a more global fit.
Off-Shell Higgs Probe of Naturalness
Gonçalves, Dorival; Han, Tao; Mukhopadhyay, Satyanarayan
2018-03-01
Examining the Higgs sector at high energy scales through off-shell Higgs production can potentially shed light on the naturalness problem of the Higgs boson mass. We propose such a study at the LHC by utilizing a representative model with a new scalar field (S ) coupled to the standard model Higgs doublet (H ) in a form |S |2|H |2. In the process p p →h*→Z Z , the dominant momentum-dependent part of the one-loop scalar singlet corrections, especially above the new threshold at 2 mS, leads to a measurable deviation in the differential distribution of the Z -pair invariant mass, in accordance with the quadratic divergence cancellation to the Higgs mass. We find that it is conceivable to probe such new physics at the 5 σ level at the high-luminosity LHC, improving further with the upgraded 27 TeV LHC, without requiring the precise measurement of the Higgs boson total width. The discovery of such a Higgs portal could also have important implications for thermal dark matter as well as for electroweak baryogenesis.
CP Violation in Heavy MSSM Higgs Scenarios
Carena, M; Lee, J S; Pilaftsis, A; Wagner, C E M
2016-01-01
We introduce and explore new heavy Higgs scenarios in the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation, which have important phenomenological implications that may be testable at the LHC. For soft supersymmetry-breaking scales M_S above a few TeV and a charged Higgs boson mass M_H+ above a few hundred GeV, new physics effects including those from explicit CP violation decouple from the light Higgs boson sector. However, such effects can significantly alter the phenomenology of the heavy Higgs bosons while still being consistent with constraints from low-energy observables, for instance electric dipole moments. To consider scenarios with a charged Higgs boson much heavier than the Standard Model (SM) particles but much lighter than the supersymmetric particles, we revisit previous calculations of the MSSM Higgs sector. We compute the Higgs boson masses in the presence of CP violating phases, implementing improved matching and renormalization group (RG) effects, as well as two-loop RG...
A tale of twin Higgs: natural twin two Higgs doublet models
International Nuclear Information System (INIS)
Yu, Jiang-Hao
2016-01-01
In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit ℤ 2 breaking term. Introducing additional twin Higgs could accommodate spontaneous ℤ 2 breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and ℤ 2 symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit ℤ 2 breaking, radiative ℤ 2 breaking, tadpole-induced ℤ 2 breaking, and quartic-induced ℤ 2 breaking. We investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.
Probing the Higgs self coupling via single Higgs production at the LHC
Energy Technology Data Exchange (ETDEWEB)
Degrassi, G. [Dipartimento di Matematica e Fisica, Università di Roma Tre andINFN, sezione di Roma Tre,Via della Vasca Navale 84, I-00146 Rome (Italy); Giardino, P.P. [Physics Department, Brookhaven National Laboratory,20 Pennsylvania St., Upton NY 11742 (United States); Maltoni, F.; Pagani, D. [Centre for Cosmology, Particle Physics and Phenomenology (CP3),Université Catholique de Louvain,B-1348 Louvain-la-Neuve (Belgium)
2016-12-16
We propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. The method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production (ggF, VBF, WH, ZH, tt̄H) and decay (γγ, WW{sup ∗}/ZZ{sup ∗}→4f, bb̄, ττ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We find that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.
A tale of twin Higgs: natural twin two Higgs doublet models
Energy Technology Data Exchange (ETDEWEB)
Yu, Jiang-Hao [Amherst Center for Fundamental Interactions, Department of Physics,University of Massachusetts Amherst,710 North Pleasant St., Amherst, MA 01002 (United States)
2016-12-28
In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit ℤ{sub 2} breaking term. Introducing additional twin Higgs could accommodate spontaneous ℤ{sub 2} breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and ℤ{sub 2} symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit ℤ{sub 2} breaking, radiative ℤ{sub 2} breaking, tadpole-induced ℤ{sub 2} breaking, and quartic-induced ℤ{sub 2} breaking. We investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.
Two Higgs Doublet Model and Model Independent Interpretation of Neutral Higgs Boson Searches
Abbiendi, G.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, John; Anderson, K.J.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Bailey, I.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Baumann, S.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; de Roeck, A.; de Wolf, E.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanti, M.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Glenzinski, D.; Goldberg, J.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauke, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lawson, I.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; Lillich, J.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rembser, C.; Renkel, P.; Rick, H.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Stoll, K.; Strom, David M.; Strohmer, R.; Stumpf, L.; Surrow, B.; Talbot, S.D.; Tarem, S.; Taylor, R.J.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Vachon, B.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.
2001-01-01
Searches for the neutral Higgs bosons h0 and A0, are used to obtain limits on the Type II Two Higgs Doublet Model (2HDM(II)) with no CP-violation in the Higgs sector and no additional particles besides the five Higgs bosons. The analysis combines approximately 170 pb-1 of data collected with the OPAL detector at sqrt{s} ~ 189 GeV with previous runs at sqrt{s} ~ mZ and sqrt{s} ~ 183 GeV. The searches are sensitive to the h0, A0 -> qq, gg, tau+tau- and h0 -> A0A0 decay modes of the Higgs bosons. For the first time, the 2HDM(II) parameter space is explored in a detailed scan, and new flavour independent analyses are applied to examine regions in which the neutral Higgs bosons decay predominantly into light quarks or gluons. Model-independent limits are also given.
Falkowski, A.; Kaminska, A.; Pokorski, S.; Weiler, A.
2011-01-01
In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully identify regions of parameter space where a minimal addition - a single spin-1 custodial SU(2) triplet resonance - allows one to retain perturbative control in all channels. Elastic scattering of longitudinal W and Z bosons alone seems to permit a very large cut-off beyond the Naive Dimensional Analysis expectation. We find however that including scattering of the spin-1 resonances then leads to an earlier onset of strong coupling. Most importantly for LHC searches, we define a self-consistent set-up with a well-defined range of validity without recourse to unitarization schemes whose physical meaning is obscure. We discuss the LHC phenomenology and the discovery reach for these electroweak resonances and mention the possibility of a nightmare scenario with no Higgs nor resonan...
Twin Higgs Asymmetric Dark Matter.
García García, Isabel; Lasenby, Robert; March-Russell, John
2015-09-18
We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20 GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.
Energy Technology Data Exchange (ETDEWEB)
Falkowski, A. [Paris-Sud, Orsay (France). Lab. de Physique Theorique d' Orsay; Grojean, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Institut de Physique Theorique, CEA/Saclay, Gif-sur-Yvette (France); Kaminska, A. [Warsaw Univ. (Poland). Inst. of Theoretical Physics; Pokorski, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Warsaw Univ. (Poland). Inst. of Theoretical Physics; Weiler, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2011-09-15
In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully identify regions of parameter space where a minimal addition - a single spin-1 SU(2){sub custodial}-triplet resonance - allows one to retain perturbative control in all channels. Elastic scattering of longitudinal W and Z bosons alone seems to permit a very large cut-off beyond the Naive Dimensional Analysis expectation. We find however that including scattering of the spin-1 resonances then leads to an earlier onset of strong coupling. Most importantly for LHC searches, we define a self-consistent set-up with a well-defined range of validity without recourse to unitarization schemes whose physical meaning is obscure. We discuss the LHC phenomenology and the discovery reach for these electroweak resonances and mention the possibility of a nightmare scenario with no Higgs nor resonance within the LHC reach. Finally, we discuss the effects of parity breaking in the heavy resonance sector which reduces the contributions to the S parameter. (orig.)
Alchemical inflation: inflaton turns into Higgs
Nakayama, Kazunori; Takahashi, Fuminobu
2012-11-01
We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field.
Alchemical inflation: inflaton turns into Higgs
International Nuclear Information System (INIS)
Nakayama, Kazunori; Takahashi, Fuminobu
2012-01-01
We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field
Spacetime Curvature and Higgs Stability after Inflation.
Herranen, M; Markkanen, T; Nurmi, S; Rajantie, A
2015-12-11
We investigate the dynamics of the Higgs field at the end of inflation in the minimal scenario consisting of an inflaton field coupled to the standard model only through the nonminimal gravitational coupling ξ of the Higgs field. Such a coupling is required by renormalization of the standard model in curved space, and in the current scenario also by vacuum stability during high-scale inflation. We find that for ξ≳1, rapidly changing spacetime curvature at the end of inflation leads to significant production of Higgs particles, potentially triggering a transition to a negative-energy Planck scale vacuum state and causing an immediate collapse of the Universe.
Higgs measurements in the diboson final state
Nomidis, Ioannis; The ATLAS collaboration
2018-01-01
This article summarises recent measurements of the Higgs boson properties using its diboson final states performed with 36.1 fb$^{−1}$ of data collected with the ATLAS detector in 13 TeV proton-proton collisions at the LHC. Two most recent results are highlighted: the measurement of the Higgs production cross-section from gluon-gluon fusion and vector-boson-fusion modes with the $H \\to WW^*$ decay and also a measurement of the Higgs boson production combining the differential cross-sections of $H \\to ZZ^∗$ and $H \\to \\gamma\\gamma$ decay channels.
Improved formalism for precision Higgs coupling fits
Energy Technology Data Exchange (ETDEWEB)
Barklow, Tim; Peskin, Michael E. [Stanford Univ., Menlo Park, CA (United States). Stanford Linear Accelerator Center; Fujii, Keisuke; Ogawa, Tomohisa [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Jung, Sunghoon [Stanford Univ., Menlo Park, CA (United States). Stanford Linear Accelerator Center; Seoul National Univ. (Korea, Republic of). Dept. of Physics and Astronomy; Karl, Robert; List, Jenny [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Tian, Junping [Tokyo Univ. (Japan). International Center for Elementary Particle Physics (ICEPP)
2017-08-15
Future e{sup +}e{sup -} colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e{sup +}e{sup -} data, based on the Effective Field Theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e{sup +}e{sup -} colliders.
Measuring the Higgs mass at TESLA
International Nuclear Information System (INIS)
Garcia-Abia, P.; Lohmann, W.; Raspereza, A.
2001-01-01
We report on the accuracy of the measurement of the Higgs boson mass that would be achieved in a linear collider operating at a center-of-mass energy of 350 GeV, assuming an integrated luminosity of 500 fb-1. For that we have exploited the exclusive Higgs decays into b quarks and W bosons. The Higgs mass is determined with an accuracy of about 40 MeV for m H =120 GeV and 80 MeV for m H =180 GeV
Neutral Naturalness from Orbifold Higgs Models
Craig, Nathaniel; Knapen, Simon; Longhi, Pietro
2015-02-01
We present a general class of natural theories in which the Higgs boson is a pseudo-Goldstone boson in an orbifolded gauge theory. The symmetry protecting the Higgs boson at low energies is an accidental global symmetry of the quadratic action, rather than a full continuous symmetry. The lightest degrees of freedom protecting the weak scale carry no standard model (SM) quantum numbers and interact with visible matter principally through the Higgs portal. This opens the door to the systematic study of "neutral naturalness": natural theories with SM-neutral states that are as yet untested by the LHC.
The hunt for the Higgs particle
CERN. Geneva
2003-01-01
This series of lectures will cover experimental search strategies for the Higgs boson from LEP to LHC/Tevatron and to a possible e+e- linear collider (NLC). The emphasis will be on specific benchmark decay channels, e.g. H->bb, H->ZZ->4 leptons, H->WW->lvjj, in terms of signal reconstruction and background rejection, on Higgs boson searches in supersymmetric models, and on precise measurements of the Higgs boson properties if it were to be discovered at one of the future machines.
A light Higgs Boson would invite Supersymmmetry
Ellis, Jonathan Richard; Ellis, John; Ross, Douglas
2001-01-01
If the Higgs boson weighs about 115 GeV, the effective potential of the Standard Model becomes unstable above a scale of about 10^6 GeV. This instability may be rectified only by new bosonic particles such as stop squarks. However, avoiding the instability requires fine-tuning of the model couplings, in particular if the theory is not to become non-perturbative before the Planck scale. Such fine-tuning is automatic in a supersymmetric model, but is lost if there are no Higgsinos. A light Higgs boson would be prima facie evidence for supersymmetry in the top-quark and Higgs sectors.
Standard model Higgs physics at colliders
International Nuclear Information System (INIS)
Rosca, A.
2007-01-01
In this report we briefly review the experimental status and prospects to verify the Higgs mechanism of spontaneous symmetry breaking. The focus is on the most relevant aspects of the phenomenology of the Standard Model Higgs boson at current (Tevatron) and future (Large Hadron Collider, LHC and International Linear Collider, ILC) particle colliders. We review the Standard Model searches: searches at the Tevatron, the program planned at the LHC and prospects at the ILC. Emphasis is put on what follows after a candidate discovery at the LHC: the various measurements which are necessary to precisely determine what the properties of this Higgs candidate are. (author)
Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa Model
Energy Technology Data Exchange (ETDEWEB)
Gerhold, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany); Jansen, K. [John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany)
2010-02-15
We establish the cutoff-dependent upper Higgs boson mass bound by means of direct lattice computations in the framework of a chirally invariant lattice Higgs-Yukawa model emulating the same chiral Yukawa coupling structure as in the Higgs-fermion sector of the Standard Model. As expected from the triviality picture of the Higgs sector, we observe the upper mass bound to decrease with rising cutoff parameter {lambda}. Moreover, the strength of the fermionic contribution to the upper mass bound is explored by comparing to the corresponding analysis in the pure {phi}{sup 4}-theory. (orig.)
Higgs Production and Decay in Models of a Warped Extra Dimension with a Bulk Higgs
Archer, Paul R.; Carena, Marcela; Carmona, Adrian; Neubert, Matthias
2014-01-01
Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS$_5$ space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusio...
Some decays of neutral Higgs bosons in the NMSSM
International Nuclear Information System (INIS)
Cuong, Nguyen Chinh; Trang, Do Thi Thu; Thuy, Nguyen Thi Phuong
2014-01-01
To solve the μ problem of the Minimal Supersymmetric Standard Model (MSSM), a single field S is added to build the Next Minimal Supersymmetric Standard Model (NMSSM). Vacuum enlarged with non-zero vevs of the neutral-even CP is the combination of H u , H d and S. In the NMSSM, the higgs sector is increased to 7 higgs (compared with 5 higgs in the MSSM), including three higgs which are even-CP h 1,2,3 (m h1 < m h2 < m h3 ), two higgs which are odd-CP a 1,2 (m a1 < m a2 ) and a couple of charged higgs H ± . The decays higgs into higgs is one of the remarkable new points of the NMSSM. In this paper we study some decays of neutral Higgs bosons. The numerical results are also presented together with evaluations.
Stable Higgs Bosons - new candidate for cold dark matter
International Nuclear Information System (INIS)
Hosotani, Yutaka
2010-01-01
The Higgs boson is in the backbone of the standard model of electroweak interactions. It must exist in some form for achieving unification of interactions. In the gauge-Higgs unification scenario the Higgs boson becomes a part of the extra-dimensional component of gauge fields. The Higgs boson becomes absolutely stable in a class of the gauge-Higgs unification models, serving as a promising candidate for cold dark matter in the universe. The observed relic abundance of cold dark matter is obtained with the Higgs mass around 70 GeV. The Higgs-nucleon scattering cross section is found to be close to the recent CDMS II XENON10 bounds in the direct detection of dark matter. In collider experiments stable Higgs bosons are produced in a pair, appearing as missing energies momenta so that the way of detecting Higgs bosons must be altered.
Are Higgs particles strongly interacting(question mark)
International Nuclear Information System (INIS)
Shanker, O.
1982-02-01
The order of magnitude of Yukawa couplings in some theories with flavour violating Higgs particles is estimated. Based on these couplings, mass bounds for flavour violating Higgs particles are derived from the Ksub(L)-Ksub(S) mass difference. The Higgs particles have to be very heavy, implying that the Higgs sector quartic couplings are very large. Thus, these theories seem to require a strongly interacting Higgs sector unless one adjusts to the Higgs-fermion Yukawa couplings to within two orders of magnitude, so as to suppress the coupling of Higgs particles to the flavour-violating anti sd current. Most models with flavour violating Higgs particles have the same general features, so the conclusions are likely to hold for a wide class of models with flavour violating Higgs particles
Energy Technology Data Exchange (ETDEWEB)
Lachos, A. [Instituto Nacional de Enfermedades Neoplasicas, Departamento de Radioterapia, Av. Angamos Este 2520, Surquillo, Lima (Peru); Marquez, J. F., E-mail: alachosd1271@yahoo.com [Univesidad Nacional Mayor de San Marcos, Facultad de Ciencias Fisicas, C. German Amezaga 375, Ciudad Univesitaria, Lima (Peru)
2014-08-15
The radiological accident happened in the Chilca District, the Canete County at 60 km to the south of Lima-Peru, during the night of January 11 to 12, 2012. The physical reconstruction of the accident was carried out in January 21, 2012, by means of the information gathering administrative and technical of the radioactive source as well as of the installation, the personnel and the involved procedures in the accidental event, information of the space geometry where the event took place. The preliminary information indicates that the source could have been locked in the guide tube of the equipment, next to the collimator in the first takes radiographic. The radiation monitors were not activated on the procedure, impeding this way, not to realize the flaw and causing that the personnel were exposed to the radiation during the whole work period. Their hands and especially their fingers would have been only to some millimeters of the source. With the obtained information and the measurements of the exposure rates of the radioactive source, was carried out the dose calculation to total body, the dose received in the hands and the dose received in the index finger of the left hand. The accident happened by operative procedure breach, by lack of training of the operators. The physical reconstruction of the accident contributes fundamental information for the decisions taking in the medical management of the accidents by radiation. (author)
Light Higgs production at the Compton Collider
International Nuclear Information System (INIS)
Jikia, G.; Soeldner-Rembold, S.
2000-01-01
We have studied the production of a light Higgs boson with a mass of 120 GeV in photon-photon collisions at a Compton collider. The event generator for the backgrounds to a Higgs signal due to b-barb and c-barc heavy quark pair production in polarized γγ collisions is based on a complete next-to-leading order (NLO) perturbative QCD calculation. For J z = 0 the large double-logarithmic corrections up to four loops are also included. It is shown that the two-photon width of the Higgs boson can be measured with high statistical accuracy of about 2% for integrated γγ luminosity in the hard part of the spectrum of 40 fb -1 . As a result the total Higgs boson width can be calculated in a model independent way to an accuracy of about 14%
Light Higgs production at a photon collider
Söldner-Rembold, S
2001-01-01
We present a preliminary study of the production of a light Higgs boson with a mass between 120 and 160 GeV in photon-photon collisions at a Compton collider. The event generator for the backgrounds to a Higgs signal due to b-barb and c-barc heavy quark pair production in polarized gamma gamma collisions is based on a complete next-to-leading order (NLO) perturbative QCD calculation. For J sub z =0 the large double-logarithmic corrections up to four loops are also included. It is shown that the two-photon width of the Higgs boson can be measured with high statistical accuracy of about 2-10% for integrated gamma gamma luminosity in the hard part of the spectrum of 43 fb sup - sup 1. From this result the total Higgs boson width can be derived in a model independent way.
Renormalization group flow of the Higgs potential.
Gies, Holger; Sondenheimer, René
2018-03-06
We summarize results for local and global properties of the effective potential for the Higgs boson obtained from the functional renormalization group, which allows one to describe the effective potential as a function of both scalar field amplitude and renormalization group scale. This sheds light onto the limitations of standard estimates which rely on the identification of the two scales and helps in clarifying the origin of a possible property of meta-stability of the Higgs potential. We demonstrate that the inclusion of higher-dimensional operators induced by an underlying theory at a high scale (GUT or Planck scale) can relax the conventional lower bound on the Higgs mass derived from the criterion of absolute stability.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).
Very boosted Higgs in gluon fusion
Grojean, Christophe; Schlaffer, Matthias; Weiler, Andreas
2014-01-01
The Higgs production and decay rates offer a new way to probe new physics beyond the Standard Model. While dynamics aiming at alleviating the hierarchy problem generically predict deviations in the Higgs rates, the current experimental analyses cannot resolve the long- and short-distance contributions to the gluon fusion process and thus cannot access directly the coupling between the Higgs and the top quark. We investigate the production of a boosted Higgs in association with a high-transverse momentum jet as an alternative to the $t\\bar{t}h$ channel to pin down this crucial coupling. Presented first in the context of an effective field theory, our analysis is then applied to models of partial compositeness at the TeV scale and of natural supersymmetry.
Updated Global Analysis of Higgs Couplings
Ellis, John
2013-01-01
There are many indirect and direct experimental indications that the new particle H discovered by the ATLAS and CMS Collaborations has spin zero and (mostly) positive parity, and that its couplings to other particles are correlated with their masses. Beyond any reasonable doubt, it is a Higgs boson, and here we examine the extent to which its couplings resemble those of the single Higgs boson of the Standard Model. Our global analysis of its couplings to fermions and massive bosons determines that they have the same relative sign as in the Standard Model. We also show directly that these couplings are highly consistent with a dependence on particle masses that is linear to within a few %, and scaled by the conventional electroweak symmetry-breaking scale to within 10%. We also give constraints on loop-induced couplings, on the total Higgs decay width, and on possible invisible decays of the Higgs boson under various assumptions.
Prospects for Higgs search at D
Indian Academy of Sciences (India)
- terize the Higgs sector of the standard model. The minimal version of the standard model requires a single scalar particle, though many extensions predict additional particles. Fits to the global set of electroweak data provide an indirect upper ...
CERN collider homes in on Higgs boson
Abbott, A
1999-01-01
Last week LEP was pushed beyond its design limits when the electron and positron beams acheived energies of 200 GeV. According to some physicists, this level could be high enough to detect the Higgs boson (4 paragraphs).
Partially natural Two Higgs Doublet Models
Energy Technology Data Exchange (ETDEWEB)
Draper, Patrick [Department of Physics, University of California,Broida Hall, Santa Barbara, CA 93106 (United States); Haber, Howard E. [Santa Cruz Institute for Particle Physics, University of California,1156 High Street, Santa Cruz, CA 95064 (United States); Kavli Institute for Theoretical Physics, University of California,Kohn Hall, Santa Barbara, CA 93106 (United States); Ruderman, Joshua T. [Center for Cosmology and Particle Physics, Department of Physics, New York University,4 Washington Pl. New York, NY 10003 (United States)
2016-06-21
It is possible that the electroweak scale is low due to the fine-tuning of microscopic parameters, which can result from selection effects. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would seem to disfavor this possibility, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. We discuss counterexamples where the Higgs boson is light because of fine-tuning, and a second scalar doublet is light because a discrete symmetry relates its mass to the mass of the Standard Model Higgs boson. Our examples require new vectorlike fermions at the electroweak scale, and the models possess a rich electroweak vacuum structure. The mechanism that we discuss does not protect a small CP-odd Higgs mass in split or high-scale supersymmetry-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.
Superheavy dark matter through Higgs portal operators
Kolb, Edward W.; Long, Andrew J.
2017-11-01
The WIMPzilla hypothesis is that the dark matter is a super-weakly-interacting and superheavy particle. Conventionally, the WIMPzilla abundance is set by gravitational particle production during or at the end of inflation. In this study we allow the WIMPzilla to interact directly with Standard Model fields through the Higgs portal, and we calculate the thermal production (freeze-in) of WIMPzilla dark matter from the annihilation of Higgs boson pairs in the plasma. The two particle-physics model parameters are the WIMPzilla mass and the Higgs-WIMPzilla coupling. The two cosmological parameters are the reheating temperature and the expansion rate of the universe at the end of inflation. We delineate the regions of parameter space where either gravitational or thermal production is dominant, and within those regions we identify the parameters that predict the observed dark matter relic abundance. Allowing for thermal production opens up the parameter space, even for Planck-suppressed Higgs-WIMPzilla interactions.
Very boosted Higgs in gluon fusion
Energy Technology Data Exchange (ETDEWEB)
Grojean, C. [Univ. Autonoma de Barcelona, Bellaterra (Spain). ICREA at IFAE; Salvioni, E. [California Univ., Davis, CA (United States). Dept. of Physics; European Organization for Nuclear Research (CERN), Geneva (Switzerland); Padova Univ. (Italy). Dipt. di Fisica e Astronomica; INFN, Sezione di Padova (Italy); Schlaffer, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Weiler, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2013-12-15
The Higgs production and decay rates offer a new way to probe new physics beyond the Standard Model. While dynamics aiming at alleviating the hierarchy problem generically predict deviations in the Higgs rates, the current experimental analyses cannot resolve the long- and short-distance contributions to the gluon fusion process and thus cannot access directly the coupling between the Higgs and the top quark. We investigate the production of a boosted Higgs in association with a high-transverse momentum jet as an alternative to the t anti th channel to pin down this crucial coupling. Presented rst in the context of an effective field theory, our analysis is then applied to models of partial compositeness at the TeV scale and of natural supersymmetry.
LHC Higgs physics beyond the Standard Model
International Nuclear Information System (INIS)
Spannowsky, M.
2007-01-01
The Large Hadron Collider (LHC) at CERN will be able to perform proton collisions at a much higher center-of-mass energy and luminosity than any other collider. Its main purpose is to detect the Higgs boson, the last unobserved particle of the Standard Model, explaining the riddle of the origin of mass. Studies have shown, that for the whole allowed region of the Higgs mass processes exist to detect the Higgs at the LHC. However, the Standard Model cannot be a theory of everything and is not able to provide a complete understanding of physics. It is at most an effective theory up to a presently unknown energy scale. Hence, extensions of the Standard Model are necessary which can affect the Higgs-boson signals. We discuss these effects in two popular extensions of the Standard Model: the Minimal Supersymmetric Standard Model (MSSM) and the Standard Model with four generations (SM4G). Constraints on these models come predominantly from flavor physics and electroweak precision measurements. We show, that the SM4G is still viable and that a fourth generation has strong impact on decay and production processes of the Higgs boson. Furthermore, we study the charged Higgs boson in the MSSM, yielding a clear signal for physics beyond the Standard Model. For small tan β in minimal flavor violation (MFV) no processes for the detection of a charged Higgs boson do exist at the LHC. However, MFV is just motivated by the experimental agreement of results from flavor physics with Standard Model predictions, but not by any basic theoretical consideration. In this thesis, we calculate charged Higgs boson production cross sections beyond the assumption of MFV, where a large number of free parameters is present in the MSSM. We find that the soft-breaking parameters which enhance the charged-Higgs boson production most are just bound to large values, e.g. by rare B-meson decays. Although the charged-Higgs boson cross sections beyond MFV turn out to be sizeable, only a detailed
LHC Higgs physics beyond the Standard Model
Energy Technology Data Exchange (ETDEWEB)
Spannowsky, M.
2007-09-22
The Large Hadron Collider (LHC) at CERN will be able to perform proton collisions at a much higher center-of-mass energy and luminosity than any other collider. Its main purpose is to detect the Higgs boson, the last unobserved particle of the Standard Model, explaining the riddle of the origin of mass. Studies have shown, that for the whole allowed region of the Higgs mass processes exist to detect the Higgs at the LHC. However, the Standard Model cannot be a theory of everything and is not able to provide a complete understanding of physics. It is at most an effective theory up to a presently unknown energy scale. Hence, extensions of the Standard Model are necessary which can affect the Higgs-boson signals. We discuss these effects in two popular extensions of the Standard Model: the Minimal Supersymmetric Standard Model (MSSM) and the Standard Model with four generations (SM4G). Constraints on these models come predominantly from flavor physics and electroweak precision measurements. We show, that the SM4G is still viable and that a fourth generation has strong impact on decay and production processes of the Higgs boson. Furthermore, we study the charged Higgs boson in the MSSM, yielding a clear signal for physics beyond the Standard Model. For small tan {beta} in minimal flavor violation (MFV) no processes for the detection of a charged Higgs boson do exist at the LHC. However, MFV is just motivated by the experimental agreement of results from flavor physics with Standard Model predictions, but not by any basic theoretical consideration. In this thesis, we calculate charged Higgs boson production cross sections beyond the assumption of MFV, where a large number of free parameters is present in the MSSM. We find that the soft-breaking parameters which enhance the charged-Higgs boson production most are just bound to large values, e.g. by rare B-meson decays. Although the charged-Higgs boson cross sections beyond MFV turn out to be sizeable, only a detailed
Higgs Decay to Photons at Two Loops
International Nuclear Information System (INIS)
Fugel, F.
2007-01-01
The calculation of the two-loop corrections to the partial width of an intermediate-mass Higgs boson decaying into a pair of photons is reviewed. The main focus lies on the electroweak (EW) contributions. The sum of the EW corrections ranges from -4% to 0% for a Higgs mass between 100 GeV and 150 GeV, while the complete correction at two-loop order amounts to less than ± 1.5% in this regime. (author)
Exclusive Higgs production at the LHC
Energy Technology Data Exchange (ETDEWEB)
Dechambre, Alice [Universite de Liege, Institut d' Astrophysique et de Geophysique, Allee du 6 aout, 17 - Bat. B5c, B-4000 Liege 1 - Sart-Tilman (Belgium); Staszewski, Rafal [IRFU/SPP, CEA-Saclay, bat. 141, 91191 Gif-sur-Yvette Cedex (France); Henryk Niewodniczanski, Institute of Nuclear Physics - PAN, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Royon, Christophe [IRFU/SPP, CEA-Saclay, bat. 141, 91191 Gif-sur-Yvette Cedex (France)
2010-07-01
After a brief description of the models of exclusive diffractive Higgs production, we first evaluate the theoretical uncertainties that affect the calculation of exclusive cross section (jets, Higgs...). In addition, in view of the recent measurement of exclusive di-jet at CDF and the new implementation of the corresponding cross section in FPMC (Forward Physics Monte-Carlo), we developed an analysis strategy that can be used to narrow down these uncertainties with the help of early LHC measurement. (authors)
CERN. Geneva
2013-01-01
The recent discovery of a Higgs boson is a milestone in a half century long strive to unravel the origins of electroweak symmetry breaking. In the successful first three years of LHC operations at the energy frontier, the quest of Higgs bosons went from the era of searches, to the discovery and more recently on to the era of measurements of its properties. An overview of the these three phases, the implications of the discovery and future prospects will be discussed.
CMS: Simulated Higgs production and decay
David Barney
2005-01-01
This track is an example of simulated data modelled for the CMS detector on the Large Hadron Collider (LHC) at CERN, which will begin taking data in 2008. These graphics show two possible signatures that a Higgs boson may leave in the detector. As the Higgs will be very short-lived, it cannot be observed directly but rather its production is inferred from the products of its decay.
Discovery of the Higgs boson and beyond
International Nuclear Information System (INIS)
Godbole, Rohini
2014-01-01
This talk is about the Higgs mechanism, the theoretical discovery of which, was awarded the 2013 Nobel Prize. It also discusses the discovery of the Higgs boson at the large hadron collider which provided the experimental proof that made the Nobel prize possible. It covers the implications of these for the quest of unravelling the fundamental laws of nature which seem to govern both, the behavior of the ultra small (subatomic particles) and the ultra large (the cosmos)
International Nuclear Information System (INIS)
Cahn, R.; Froidevaux, D.; Grivaz, J.F.; King, S.F.; Mansoulie, B.; Taxil, P.
1990-01-01
The 22th session of Summer School on Particle Physics was held in Strasbourg from 3 to 7 September 1990. The subject 'Where is the Higgs' and all aspects of this question have been studied in lessons and discussions: actual researches of Higgs at LEP in the Standard Model or not, future researches in hadron collisions of very high energy and hard technical problems that the experiments set near to the future hadron colliders
PRECISION ELECTROWEAK MEASUREMENTS AND THE HIGGS MASS
International Nuclear Information System (INIS)
MARCIANO, W.J.
2004-01-01
The utility of precision electroweak measurements for predicting the Standard Model Higgs mass via quantum loop effects is discussed. Current constraints from m w and sin 2 θ w (m z ) ovr MS imply a relatively light Higgs ∼< 154 GeV which is consistent with Supersymmetry expectations. The existence of Supersymmetry is further suggested by a discrepancy between experiment and theory for the muon anomalous magnetic moment. Constraints from precision studies on other types of ''New Physics'' are also briefly described
Little Higgs models and T parity
International Nuclear Information System (INIS)
Perelstein, Maxim
2006-01-01
Little Higgs models are an interesting extension of the standard model at the TeV scale. They provide a simple and attractive mechanism of electroweak symmetry breaking. We review one of the simplest models of this class, the littlest Higgs model, and its extension with T parity. The model with T parity satisfies precision electroweak constraints without fine-tuning, contains an attractive dark matter candidate, and leads to interesting phenomenology at the Large Hadron Collider (LHC). (author)
Discovering uncolored naturalness in exotic Higgs decays
International Nuclear Information System (INIS)
Curtin, David; Verhaaren, Christopher B.
2015-01-01
Solutions to the hierarchy problem usually require top partners. In standard SUSY or composite Higgs theories, the partners carry SM color and are becoming increasingly constrained by LHC searches. However, theories like Folded SUSY (FS), Twin Higgs (TH) and Quirky Little Higgs (QLH) introduce uncolored top partners, which can be SM singlets or carry electroweak charge. Their small production cross section left doubt as to whether the LHC can effectively probe such scenarios. Typically, these partners are charged under their own mirror color gauge group. In FS and QLH, the absence of light mirror matter allows glueballs to form at the bottom of the mirror spectrum. This is also the case in some TH realizations. The Higgs can decay to these mirror glueballs, with the glueballs decaying into SM particles with potentially observable lifetimes. We undertake the first detailed study of this glueball signature and quantitatively demonstrate the discovery potential of uncolored naturalness via exotic Higgs decays at the LHC and a potential future 100 TeV collider. Our findings indicate that mirror glueballs are the smoking gun signature of natural FS and QLH type theories, in analogy to tree-level Higgs coupling shifts for the TH. We show that glueball masses in the ∼10–60 GeV mass range are theoretically preferred. Careful treatment of lifetime, mirror-hadronization and nonperturbative uncertainties is required to perform meaningful collider studies. We outline several new search strategies for exotic Higgs decays of the form h→XX→4f at the LHC, with X having lifetimes in the 10μm to km range. We find that FS stops can be probed with masses up to 600 (1100) GeV at the LHC with 300 (3000) fb −1 of data, and TH top partners could be accessible with masses up to 900 (1500) GeV. This makes exotic Higgs decays the prime discovery channel for uncolored naturalness at the LHC.
Probing the Higgs vacuum with general relativity
Mannheim, Philip D.; Kazanas, Demosthenes
1991-01-01
It is shown that the structure of the Higgs vacuum can be revealed in gravitational experiments which probe the Schwarzschild geometry to only one order in MG/r beyond that needed for the classical tests of general relativity. The possibility that deviations from the conventional geometry are at least theoretically conceivable is explored. The deviations obtained provide a diagnostic test for searching for the existence of macroscopic scalar fields and open up the possiblity for further exploring the Higgs mechanism.
Electroweak Calibration of the Higgs Characterization Model
CERN. Geneva
2015-01-01
I will present the preliminary results of histogram fits using the Higgs Combine histogram fitting package. These fits can be used to estimate the effects of electroweak contributions to the p p -> H mu+ mu- Higgs production channel and calibrate Beyond Standard Model (BSM) simulations which ignore these effects. I will emphasize my findings' significance in the context of other research here at CERN and in the broader world of high energy physics.
International Nuclear Information System (INIS)
Cipriano, P.; Dooling, S.; Grebenyuk, A.; Gunnellini, P.; Katsas, P.; Hautmann, F.; Oxford Univ.; Jung, H.; Antwerpen Univ.
2013-08-01
In the forthcoming high-luminosity phase at the LHC many of the most interesting QCD measurements so far become prohibitively difficult due to the high pile-up. We suggest a program of QCD measurements based on the observed Higgs boson which can be started now and can be carried through also in the large pile-up environment at high luminosity. It focuses on gluonic processes at high mass scales, and their distinctive QCD features compared to classic probes such as Drell-Yan. It explores the strong-interaction sector of the Standard Model both at high transverse momenta and at low transverse momenta, by investigating issues on gluon fusion processes which have never been addressed experimentally before. We discuss a few specific examples and present results of Monte Carlo simulations.
Energy Technology Data Exchange (ETDEWEB)
Cipriano, P.; Dooling, S.; Grebenyuk, A.; Gunnellini, P.; Katsas, P. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hautmann, F. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Oxford Univ. (United Kingdom). Dept. of Physics; Jung, H. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Antwerpen Univ. (Belgium). Elementaire Deeltjes Fysica
2013-08-15
In the forthcoming high-luminosity phase at the LHC many of the most interesting QCD measurements so far become prohibitively difficult due to the high pile-up. We suggest a program of QCD measurements based on the observed Higgs boson which can be started now and can be carried through also in the large pile-up environment at high luminosity. It focuses on gluonic processes at high mass scales, and their distinctive QCD features compared to classic probes such as Drell-Yan. It explores the strong-interaction sector of the Standard Model both at high transverse momenta and at low transverse momenta, by investigating issues on gluon fusion processes which have never been addressed experimentally before. We discuss a few specific examples and present results of Monte Carlo simulations.
Higgs Machine Learning Challenge 2014
Olivier, A-P; Bourdarios, C ; LAL / Orsay; Goldfarb, S ; University of Michigan
2014-01-01
High Energy Physics (HEP) has been using Machine Learning (ML) techniques such as boosted decision trees (paper) and neural nets since the 90s. These techniques are now routinely used for difficult tasks such as the Higgs boson search. Nevertheless, formal connections between the two research fields are rather scarce, with some exceptions such as the AppStat group at LAL, founded in 2006. In collaboration with INRIA, AppStat promotes interdisciplinary research on machine learning, computational statistics, and high-energy particle and astroparticle physics. We are now exploring new ways to improve the cross-fertilization of the two fields by setting up a data challenge, following the footsteps of, among others, the astrophysics community (dark matter and galaxy zoo challenges) and neurobiology (connectomics and decoding the human brain). The organization committee consists of ATLAS physicists and machine learning researchers. The Challenge will run from Monday 12th to September 2014.
SUSY and BSM Higgs boson searches with ATLAS and CMS
Dasu, S
2012-01-01
Results of searches for super-symmetric and other beyond the Standard Model Higgs boson searches from ATLAS and CMS experiments at the LHC arc presented. Some Standard Model (SM) higgs searches are reinterpreted in SM with four quark generations and fermio phobic models. Stringent limits) covering a large portion of the allowed parameter space in (MA, tan/3) plane are set for MSSM neutral higgs bosons decaying to T-lepton pairs, and charged higgs boson decaying to TV. Limits are set on a light NMSSM neutral higgs boson and on doubly charged higgs bosons predicted in some models are also set.
On stability of the electroweak vacuum and the Higgs portal
International Nuclear Information System (INIS)
Lebedev, Oleg
2012-03-01
In the Standard Model (SM), the Higgs mass around 125 GeV implies that the electroweak vacuum is metastable since the quartic Higgs coupling turns negative at high energies. I point out that an arbitrarily small mixing of the Higgs with a heavy singlet can make the electroweak vacuum completely stable. This is due to a tree level correction to the Higgs mass, which survives in the zero--mixing/heavy--singlet limit. Such a situation is experimentally indistinguishable from the SM, unless the Higgs self--coupling can be measured. As a result, Higgs inflation and its variants can still be viable.
On stability of the electroweak vacuum and the Higgs portal
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Oleg
2012-03-15
In the Standard Model (SM), the Higgs mass around 125 GeV implies that the electroweak vacuum is metastable since the quartic Higgs coupling turns negative at high energies. I point out that an arbitrarily small mixing of the Higgs with a heavy singlet can make the electroweak vacuum completely stable. This is due to a tree level correction to the Higgs mass, which survives in the zero--mixing/heavy--singlet limit. Such a situation is experimentally indistinguishable from the SM, unless the Higgs self--coupling can be measured. As a result, Higgs inflation and its variants can still be viable.
Higgs and new physics at high energy
International Nuclear Information System (INIS)
Solans, C.A.
2014-07-01
The observation of a new particle in the search for the Standard Model (SM) Higgs boson at the LHC, reported by the ATLAS and CMS collaborations, is a milestone in the quest to understand electroweak symmetry breaking. The evidence at the level of 5*σ for a Higgs boson-like particle has been published by both experiments after a preliminary analysis of the data from the LHC Run-I. Precision measurements of the new particle are of critical importance. ATLAS and CMS discovered a Higgs like particle with a mass close to 125.5 GeV, and measured the spin, parity and signal strength to be compatible with the one from the SM Higgs boson [J P = 0 + , μ(VBF+VH)=μ(ggH+ttH)=1]. In a coupling scale factors analysis, compatibility with the SM is found in all the tests performed, with probabilities ranging from 7% to 21%. Consequently, the Higgs physics potential of the LHC Run-I is almost exploited. Run-II and beyond will give the possibility to measure the couplings more precisely, to constrain rare decays further, and to determine a possible CP admixture of the Higgs boson
Initial conditions for critical Higgs inflation
Salvio, Alberto
2018-05-01
It has been pointed out that a large non-minimal coupling ξ between the Higgs and the Ricci scalar can source higher derivative operators, which may change the predictions of Higgs inflation. A variant, called critical Higgs inflation, employs the near-criticality of the top mass to introduce an inflection point in the potential and lower drastically the value of ξ. We here study whether critical Higgs inflation can occur even if the pre-inflationary initial conditions do not satisfy the slow-roll behavior (retaining translation and rotation symmetries). A positive answer is found: inflation turns out to be an attractor and therefore no fine-tuning of the initial conditions is necessary. A very large initial Higgs time-derivative (as compared to the potential energy density) is compensated by a moderate increase in the initial field value. These conclusions are reached by solving the exact Higgs equation without using the slow-roll approximation. This also allows us to consistently treat the inflection point, where the standard slow-roll approximation breaks down. Here we make use of an approach that is independent of the UV completion of gravity, by taking initial conditions that always involve sub-planckian energies.
The spontaneous ℤ_2 breaking Twin Higgs
International Nuclear Information System (INIS)
Beauchesne, Hugues; Earl, Kevin; Grégoire, Thomas
2016-01-01
The Twin Higgs model seeks to address the little hierarchy problem by making the Higgs a pseudo-Goldstone of a global SU(4) symmetry that is spontaneously broken to SU(3). Gauge and Yukawa couplings, which explicitly break SU(4), enjoy a discrete ℤ_2 symmetry that accidentally maintains SU(4) at the quadratic level and therefore keeps the Higgs light. Contrary to most beyond the Standard Model theories, the quadratically divergent corrections to the Higgs mass are cancelled by a mirror sector, which is uncharged under the Standard Model groups. However, the Twin Higgs with an exact ℤ_2 symmetry leads to equal vevs in the Standard Model and mirror sectors, which is phenomenologically unviable. An explicit ℤ_2 breaking potential must then be introduced and tuned against the SU(4) breaking terms to produce a hierarchy of vevs between the two sectors. This leads to a moderate but non-negligible tuning. We propose a model to alleviate this tuning, without the need for an explicit ℤ_2 breaking sector. The model consists of two SU(4) fundamental Higgses, one whose vacuum preserves ℤ_2 and one whose vacuum breaks it. As the interactions between the two Higgses are turned on, the ℤ_2 breaking is transmitted from the broken to the unbroken sector and a small hierarchy of vevs is naturally produced. The presence of an effective tadpole and feedback between the two Higgses lead to a sizable improvement of the tuning. The resulting Higgs boson is naturally very Standard Model like.
Radiative corrections to the triple Higgs coupling in the inert Higgs doublet model
International Nuclear Information System (INIS)
Arhrib, Abdesslam; Benbrik, Rachid; Falaki, Jaouad El; Jueid, Adil
2015-01-01
We investigate the implication of the recent discovery of a Higgs-like particle in the first phase of the LHC Run 1 on the Inert Higgs Doublet Model (IHDM). The determination of the Higgs couplings to SM particles and its intrinsic properties will get improved during the new LHC Run 2 starting this year. The new LHC Run 2 would also shade some light on the triple Higgs coupling. Such measurement is very important in order to establish the details of the electroweak symmetry breaking mechanism. Given the importance of the Higgs couplings both at the LHC and e + e − Linear Collider machines, accurate theoretical predictions are required. We study the radiative corrections to the triple Higgs coupling hhh and to hZZ, hWW couplings in the context of the IHDM. By combining several theoretical and experimental constraints on parameter space, we show that extra particles might modify the triple Higgs coupling near threshold regions. Finally, we discuss the effect of these corrections on the double Higgs production signal at the e + e − LC and show that they can be rather important.
Higgs boson production and decay in little Higgs models with T-parity
International Nuclear Information System (INIS)
Chen, C.-R.; Tobe, Kazuhiro; Yuan, C.-P.
2006-01-01
We study Higgs boson production and decay in a certain class of little Higgs models with T-parity in which some T-parity partners of the Standard Model (SM) fermions gain their masses through Yukawa-type couplings. We find that the Higgs boson production cross section of a 120 GeV Higgs boson at the CERN LHC via gg fusion process at one-loop level could be reduced by about 45%, 35% and 20%, as compared to its SM prediction, for a relatively low new particle mass scale f=600, 700 and 1000 GeV, respectively. On the other hand, the weak boson fusion cross section is close to the SM value. Furthermore, the Higgs boson decay branching ratio into di-photon mode can be enhanced by about 35% in small Higgs mass region in certain case, for the total decay width of Higgs boson in the little Higgs model is always smaller than that in the SM
Higgs physics at a future e+e- linear collider
International Nuclear Information System (INIS)
Schumacher, M.
2001-01-01
This letter reviews the potential of a high luminosity e + e - linear collider (LC) in the precision study of the Higgs boson profile. The complementarity with the large hadron collider (LHC) Higgs physics program is briefly discussed. At the LC the Higgs mass can be best measured exploiting the kinematics in the Higgs-strahlung process: e + e - → Z → ZH. Spin, parity and charge-conjugation quantum numbers of the Higgs boson can be determined in a model-independent way. At the LC the Higgs boson production and decay rates can be used to measure the Higgs couplings to gauge bosons and fermions. Several extensions of the SM model introduce additional Higgs doublets and singlets. A no loose theorem guarantees that in a general supersymmetric model embedded in a GUT scenario at least one Higgs boson will be observable at √s = 500 GeV with L = 500 fb -1 . At the LHC the SM Higgs boson or at least one Higgs boson in the MSSM will be observed. Beyond its discovery a limited number of measurements of Higgs boson properties can be carried out at the LHC (mass, total width for a heavy Higgs boson, some ratios of couplings). The complementary of LC over LHC concerning the Higgs sector is threefold: first the accuracy of these measurements will be increased, secondly the absolute measurements of all the relevant Higgs boson couplings, including the Higgs self coupling, will be possible only at LC, and finally extended Higgs sector scenarios can be observed at LC closing the loopholes of a possible non-discovery at the LHC
Difficult Scenarios for NMSSM Higgs Discovery at the LHC
Ellwanger, U; Hugonie, C; Ellwanger, Ulrich; Gunion, John F.; Hugonie, Cyril
2005-01-01
We identify scenarios not ruled out by LEP data in which NMSSM Higgs detection at the LHC will be particularly challenging. We first review the `no-lose' theorem for Higgs discovery at the LHC that applies if Higgs bosons do not decay to other Higgs bosons - namely, with L=300 fb^-1, there is always one or more `standard' Higgs detection channel with at least a 5 sigma signal. However, we provide examples of no-Higgs-to-Higgs cases for which all the standard signals are no larger than 7 sigma implying that if the available L is smaller or the simulations performed by ATLAS and CMS turn out to be overly optimistic, all standard Higgs signals could fall below 5 sigma even in the no-Higgs-to-Higgs part of NMSSM parameter space. In the vast bulk of NMSSM parameter space, there will be Higgs-to-Higgs decays. We show that when such decays are present it is possible for all the standard detection channels to have very small significance. In most such cases, the only strongly produced Higgs boson is one with fairly S...
International Nuclear Information System (INIS)
Yao-Bei, Liu; Hong-Mei, Han; Xue-Lei, Wang
2008-01-01
The Higgs-strahlung process e + e - → ZH and the double Higgs-strahlung process e + e - → ZHH are very important for studying Higgs boson properties and the Higgs self-coupling in the high-energy e + e - collider (ILC). We calculate the contributions of the left-right twin Higgs (LRTH) model to these processes and find that, in the favorable parameter spaces, the LRTH model can generate significant corrections to the production cross-section of these processes. We expect that the possible signals of the LRTH model can be detected via these processes in the future ILC experiments. (authors)
Higgs pair production at NLO QCD for CP-violating Higgs sectors
Gröber, R.; Mühlleitner, M.; Spira, M.
2017-12-01
Higgs pair production through gluon fusion is an important process at the LHC to test the dynamics underlying electroweak symmetry breaking. Higgs sectors beyond the Standard Model (SM) can substantially modify this cross section through novel couplings not present in the SM or the on-shell production of new heavy Higgs bosons that subsequently decay into Higgs pairs. CP violation in the Higgs sector is important for the explanation of the observed matter-antimatter asymmetry through electroweak baryogenesis. In this work we compute the next-to-leading order (NLO) QCD corrections in the heavy top quark limit, including the effects of CP violation in the Higgs sector. We choose the effective theory (EFT) approach, which provides a rather model-independent way to explore New Physics (NP) effects by adding dimension-6 operators, both CP-conserving and CP-violating ones, to the SM Lagrangian. Furthermore, we perform the computation within a specific UV-complete model and choose as benchmark model the general 2-Higgs-Doublet Model with CP violation, the C2HDM. Depending on the dimension-6 coefficients, the relative NLO QCD corrections are affected by several per cent through the new CP-violating operators. This is also the case for SM-like Higgs pair production in the C2HDM, while the relative QCD corrections in the production of heavier C2HDM Higgs boson pairs deviate more strongly from the SM case. The absolute cross sections both in the EFT and the C2HDM can be modified by more than an order of magnitude. In particular, in the C2HDM the resonant production of Higgs pairs can by far exceed the SM cross section.
Higgs pair production at NLO QCD for CP-violating Higgs sectors
Directory of Open Access Journals (Sweden)
R. Gröber
2017-12-01
Full Text Available Higgs pair production through gluon fusion is an important process at the LHC to test the dynamics underlying electroweak symmetry breaking. Higgs sectors beyond the Standard Model (SM can substantially modify this cross section through novel couplings not present in the SM or the on-shell production of new heavy Higgs bosons that subsequently decay into Higgs pairs. CP violation in the Higgs sector is important for the explanation of the observed matter-antimatter asymmetry through electroweak baryogenesis. In this work we compute the next-to-leading order (NLO QCD corrections in the heavy top quark limit, including the effects of CP violation in the Higgs sector. We choose the effective theory (EFT approach, which provides a rather model-independent way to explore New Physics (NP effects by adding dimension-6 operators, both CP-conserving and CP-violating ones, to the SM Lagrangian. Furthermore, we perform the computation within a specific UV-complete model and choose as benchmark model the general 2-Higgs-Doublet Model with CP violation, the C2HDM. Depending on the dimension-6 coefficients, the relative NLO QCD corrections are affected by several per cent through the new CP-violating operators. This is also the case for SM-like Higgs pair production in the C2HDM, while the relative QCD corrections in the production of heavier C2HDM Higgs boson pairs deviate more strongly from the SM case. The absolute cross sections both in the EFT and the C2HDM can be modified by more than an order of magnitude. In particular, in the C2HDM the resonant production of Higgs pairs can by far exceed the SM cross section.
Little Higgs model limits from LHC - Input for Snowmass 2013
International Nuclear Information System (INIS)
Reuter, Juergen; Tonini, Marco; Vries, Maikel de
2013-07-01
The status of the most prominent model implementations of the Little Higgs paradigm, the Littlest Higgs with and without discrete T parity as well as the Simplest Little Higgs are reviewed. For this, we are taking into account a fit to 21 electroweak precision observables from LEP, SLC, Tevatron together with the full 25 fb -1 of Higgs data reported from ATLAS and CMS at Moriond 2013. We also - focusing on the Littlest Higgs with T parity - include an outlook on corresponding direct searches at the 8 TeV LHC and their competitiveness with the EW and Higgs data regarding their exclusion potential. This contribution to the Snowmass procedure serves as a guideline which regions in parameter space of Little Higgs models are still compatible for the upcoming LHC runs and future experiments at the energy frontier. For this we propose two different benchmark scenarios for the Littlest Higgs with T parity, one with heavy mirror quarks, one with light ones.
Overview of the Higgs and Standard Model physics at ATLAS
Vazquez Schroeder, Tamara; The ATLAS collaboration
2018-01-01
This talk presents selected aspects of recent physics results from the ATLAS collaboration in the Standard Model and Higgs sectors, with a focus on the recent evidence for the associated production of the Higgs boson and a top quark pair.
Workshop on CP Studies and Non-Standard Higgs Physics
Accomando, E.; Akhmetzyanova, E.; Albert, J.; Alves, A.; Amapane, N.; Aoki, M.; Azuelos, G.; Baffioni, S.; Ballestrero, A.; Barger, V.; Bartl, A.; Bechtle, P.; Blanger, G.; Belhouari, A.; Bellan, R.; Belyaev, A.; Benes, Petr; Benslama, K.; Bernreuther, W.; Besanon, M.; Bevilacqua, G.; Beyer, M.; Bluj, M.; Bolognesi, S.; Boonekamp, M.; Borzumati, Francesca; Boudjema, F.; Brandenburg, A.; Brauner, Tomas; Buszello, C.P.; Butterworth, J.M.; Carena, Marcela; Cavalli, D.; Cerminara, G.; Choi, S.Y.; Clerbaux, B.; Collard, C.; Conley, John A.; Deandrea, A.; De Curtis, S.; Dermisek, R.; De Roeck, A.; Dewhirst, G.; Diaz, M.A.; Diaz-Cruz, J.L.; Dietrich, D.D.; Dolgopolov, M.; Dominici, D.; Dubinin, M.; Eboli, O.; Ellis, John R.; Evans, N.; Fano, L.; Ferland, J.; Ferrag, S.; Fitzgerald, S.P.; Fraas, H.; Franke, F.; Gennai, S.; Ginzburg, I.F.; Godbole, R.M.; Gregoire, T.; Grenier, Gerald Jean; Grojean, C.; Gudnason, S.B.; Gunion, J.F.; Haber, H.E.; Hahn, T.; Han, T.; Hankele, V.; Hays, Christopher Paul; Heinemeyer, S.; Hesselbach, S.; Hewett, J.L.; Hidaka, K.; Hirsch, M.; Hollik, W.; Hooper, D.; Hosek, J.; Hubisz, J.; Hugonie, C.; Kalinowski, J.; Kanemura, S.; Kashkan, V.; Kernreiter, T.; Khater, W.; Khoze, V.A.; Kilian, W.; King, S.F.; Kittel, O.; Klamke, G.; Kneur, J.L.; Kouvaris, C.; Kraml, S.; Krawczyk, M.; Krstonoic, P.; Kyriakis, A.; Langacker, P.; Le, M.P.; Lee, H.-S.; Lee, J.S.; Lemaire, M.C.; Liao, Y.; Lillie, B.; Litvine, Vladimir A.; Logan, H.E.; McElrath, Bob; Mahmoud, T.; Maina, E.; Mariotti, C.; Marquard, P.; Martin, A.D.; Mazumdar, K.; Miller, D.J.; Min, P.; Monig, Klaus; Moortgat-Pick, G.; Moretti, S.; Muhlleitner, M.M.; Munir, S.; Nevzorov, R.; Newman, H.; Niezurawski, P.; Nikitenko, A.; Noriega-Papaqui, R.; Okada, Y.; Osland, P.; Pilaftsis, A.; Porod, W.; Przysiezniak, H.; Pukhov, A.; Rainwater, D.; Raspereza, A.; Reuter, J.; Riemann, S.; Rindani, S.; Rizzo, T.G.; Ros, E.; Rosado, A.; Rousseau, D.; Roy, D.P.; Ryskin, M.G.; Rzehak, H.; Sannino, F.; Schmidt, E.; Schrder, H.; Schumacher, M.; Semenov, A.; Senaha, E.; Shaughnessy, G.; Singh, R.K.; Terning, J.; Vacavant, L.; Velasco, M.; Villanova del Moral, Albert; von der Pahlen, F.; Weiglein, G.; Williams, J.; Williams, K.E.; Zarnecki, A.F.; Zeppenfeld, D.; Zerwas, D.; Zerwas, P.M.; Zerwekh, A.R.; Ziethe, J.; 2nd Workshop on CP Studies and Non-standard Higgs Physics; 3rd Workshop on CP Studies and Non-standard Higgs Physics; 4th Workshop on CP Studies and Non-standard Higgs Physics; CPNSH; Workshop on CP Studies and Non-standard Higgs Physics; CP Studies and Non-Standard Higgs Physics
2006-01-01
There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents ...
Smoking-gun signatures of little Higgs models
Energy Technology Data Exchange (ETDEWEB)
Han Tao [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Institute of Theoretical Physics, Academia Sinica, Beijing 100080 (China); Logan, Heather E. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Wang, L.-T. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Jefferson Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)
2006-01-15
Little Higgs models predict new gauge bosons, fermions and scalars at the TeV scale that stabilize the Higgs mass against quadratically divergent one-loop radiative corrections. We categorize the many little Higgs models into two classes based on the structure of the extended electroweak gauge group and examine the experimental signatures that identify the little Higgs mechanism in addition to those that identify the particular little Higgs model. We find that by examining the properties of the new heavy fermion(s) at the LHC, one can distinguish the structure of the top quark mass generation mechanism and test the little Higgs mechanism in the top sector. Similarly, by studying the couplings of the new gauge bosons to the light Higgs boson and to the Standard Model fermions, one can confirm the little Higgs mechanism and determine the structure of the extended electroweak gauge group.
Higgs Pair Production as a Signal of Enhanced Yukawa Couplings
Energy Technology Data Exchange (ETDEWEB)
Bauer, Martin [Heidelberg U.; Carena, Marcela [Chicago U., KICP; Carmona, Adrián [U. Mainz, PRISMA
2017-12-31
We present a non-trivial correlation between the enhancement of the Higgs-fermion couplings and the Higgs pair production cross section in two Higgs doublet models with a flavour symmetry. This symmetry suppresses flavour-changing neutral couplings of the Higgs boson and allows for a partial explanation of the hierarchy in the Yukawa sector. After taking into account the constraints from electroweak precision measurements, Higgs coupling strength measurements, and unitarity and perturbativity bounds, we identify an interesting region of parameter space leading to enhanced Yukawa couplings as well as enhanced di-Higgs gluon fusion production at the LHC reach. This effect is visible in both the resonant and non-resonant contributions to the Higgs pair production cross section. We encourage dedicated searches based on differential distributions as a novel way to indirectly probe enhanced Higgs couplings to light fermions.
New CMS management: catching the Higgs (or non-Higgs)
Antonella del Rosso
2012-01-01
CMS, one of the two gigantic international collaborations running experiments at the LHC, has recently appointed its new management. The new spokesperson and his two deputies are well aware of the pressure associated with holding such high positions during such a historic time for particle physics. Although their focus is on the Higgs, they anticipate that other areas of CMS’ multi-purpose research programme might become equally as intriguing this year. With around 4,300 active members representing every continent and the task of uncovering some of the deepest mysteries of the Universe, CMS is constantly under the spotlight. The pressure is on to ensure the high performance of the detector while providing solutions for extremely accurate but quick data analysis. “The LHC machine is setting the pace for CMS,” explains Joseph Incandela from UC Santa Barbara/CERN, the new CMS spokesperson. “The 2012 run will most probably go to a higher energy and inten...
Castellanos, Víctor
2011-01-01
Se identificó la metodología utilizada para el catastro físico de los Asentamientos Campesinos del Estado Trujillo, durante la vigencia del Instituto Agrario Nacional, y la existente actualmente con el Instituto Nacional de Tierras, Ofi cina Regional Trujillo. La evaluación de esta información determinó la propuesta de un modelo de levantamiento con fi nes de densifi cación de redes geodésicas utilizando tecnología satelital GPS, que facilite la actualización catastral de los pred...
Systematic study of Higgs masses in the MSSM
Ghosh, B
2000-01-01
The Higgs masses in the minimal supersymmetric standard model at extremely high energies relevant to LEP2 and LHC have been studied. The results of systematic studies on Higgs masses for the possible ranges of all the parameters in the case of 1-loop radiative correction to the Higgs boson masses have been given. On the basis of detailed analyses we come to interesting constraints on the Higgs masses in the minimal supersymmetric standard model. (11 refs).
Axion and PVLAS Collaboration data in a little Higgs model
International Nuclear Information System (INIS)
Fukuyama, Takeshi; Kikuchi, Tatsuru
2006-01-01
Little Higgs models may provide a solution to the gauge hierarchy problem in the mass of the Higgs boson. In this framework the Higgs boson arises as the pseudo-Nambu-Goldstone (PNG) boson. We show that the lepton triplet introduced in a little Higgs model explains a small mass parameter in the double see-saw mechanism for neutrino masses, and it can also gives an explanation for the axionlike particle recently reported by PVLAS collaboration
Higgs pair production in the MSSM with explicit CP violation
International Nuclear Information System (INIS)
Demir, D.A.
1999-07-01
In the minimal supersymmetric standard model with explicit CP violation, associated production of the lightest Higgs boson with heavier ones is analyzed. Due to explicit CP violation, the Higgs bosons are no longer CP eigenstates so that both of the heavy Higgs bosons contribute to the process. While the radiative corrections in the Higgs sector turn out to be quite important, the vertex radiative corrections remain small as in the CP conserving theory. (author)
String tension in the three-dimensional Abelian Higgs model
International Nuclear Information System (INIS)
Farakos, K.; Koutsoumbas, G.; Sarantakos, S.
1988-01-01
We measure the expectation values of the Wilson loops for the radially active Abelian Higgs model in three dimensions with Higgs charge q = 1 and q = 2. We observe a drastic fall-off of the area term as we pass to the Higgs phase, as well as a peak of the perimetric term at the phase transition. Implications of our results for other Higgs models are also discussed. (orig.)
Higgs boson phenomenology at the LHC
International Nuclear Information System (INIS)
Kirchner, Sebastian
2016-01-01
The outstanding performance of the Large Hadron Collider (LHC) led to the discovery of the Higgs boson in 2012. The paramount endeavour after this discovery is the examination of the Higgs-boson properties, amongst others the determination of its CP quantum number and total decay width. The experimental analysis of both properties requires precise theoretical input within the Standard Model of particle physics. Theoretical methods and predictions at next-to-leading-order (NLO) in perturbative Quantum Chromodynamics (QCD), addressing the CP nature and decay width of the Higgs boson, are presented in this thesis. The thesis is split in two parts: The first part addresses the Caola-Melnikov method, which is utilised to constrain the Higgs width that is experimentally not directly measurable. The method relies on cross section measurements on and far off the Higgs boson peak. Two-loop corrections via a heavy top quark to the gluon-gluon initialised Z boson pair-production are examined as an expansion about the heavy-top limit combined with a conformal mapping and Pade approximants. The impact of the full NLO QCD corrections to the signal and background cross sections, relevant for bounding the Higgs width, is investigated. The second part of this thesis examines how precisely the CP nature of the Higgs boson can be unravelled in its decay to tau lepton pairs. All subsequent major charged-prong decays of the tau leptons are included.The impact parameter method is utilised and allows to extract the CP-mixing angle of the Higgs boson from the distribution of a signed angle. NLO QCD predictions for the signal process as well as the Drell-Yan background, including a Monte Carlo simulation of measurement uncertainties, are computed. Energy and angular correlations of the charged prongs are analysed and used to suppress the Drell-Yan background contribution. In a second step, the sensitivity to the CP-mixing angle is increased by combining the impact parameter method with the
Symmetries for SM Alignment in multi-Higgs Doublet Models
Pilaftsis, Apostolos
2016-01-01
We derive the complete set of maximal symmetries for Standard Model (SM) alignment that may occur in the tree-level scalar potential of multi-Higgs Doublet Models, with $n > 2$ Higgs doublets. Our results generalize the symmetries of SM alignment, without decoupling of large mass scales or fine-tuning, previously obtained in the context of two-Higgs Doublet Models.
The Higgs particle and higher-dimensional theories
International Nuclear Information System (INIS)
Lim, C. S.
2014-01-01
In spite of the great success of LHC experiments, we do not know whether the discovered “standard model-like” Higgs particle is really what the standard model predicts, or a particle that some new physics has in its low-energy effective theory. Also, the long-standing problems concerning the property of the Higgs and its interactions are still there, and we still do not have any conclusive argument on the origin of the Higgs itself. In this article we focus on higher-dimensional theories as new physics. First we give a brief review of their representative scenarios and closely related 4D scenarios. Among them, we mainly discuss two interesting possibilities of the origin of the Higgs: the Higgs as a gauge boson and the Higgs as a (pseudo) Nambu–Goldstone boson. Next, we argue that theories of new physics are divided into two categories, i.e., theories with normal Higgs interactions and those with anomalous Higgs interactions. Interestingly, both the candidates for the origin of the Higgs mentioned above predict characteristic “anomalous” Higgs interactions, such as the deviation of the Yukawa couplings from the standard model predictions. Such deviations can hopefully be investigated by precision tests of Higgs interactions at the planned ILC experiment. Also discussed is the main decay mode of the Higgs, H→γγ. Again, theories belonging to different categories are known to predict remarkably different new physics contributions to this important process
On the exotic Higgs decays in effective field theory.
Bélusca-Maïto, Hermès; Falkowski, Adam
2016-01-01
We discuss exotic Higgs decays in an effective field theory where the Standard Model is extended by dimension-6 operators. We review and update the status of two-body lepton- and quark-flavor-violating decays involving the Higgs boson. We also comment on the possibility of observing three-body flavor-violating Higgs decays in this context.
The standard model Higgs search at the large hadron collider
Indian Academy of Sciences (India)
Strategies are being developed to look for signatures of Higgs boson and measure its properties. In this paper results from full detector simulation-based studies on Higgs discovery from both ATLAS and CMS experiments at the LHC will be presented. Results of simulation studies on Higgs coupling measurement at LHC ...
On the exotic Higgs decays in effective field theory
Energy Technology Data Exchange (ETDEWEB)
Belusca-Maito, Hermes; Falkowski, Adam [Universite Paris-Sud, Laboratoire de Physique Theorique, Orsay (France)
2016-09-15
We discuss exotic Higgs decays in an effective field theory where the Standard Model is extended by dimension-6 operators. We review and update the status of two-body lepton- and quark-flavor-violating decays involving the Higgs boson. We also comment on the possibility of observing three-body flavor-violating Higgs decays in this context. (orig.)
Perspectives of SM Higgs measurements at the LHC
Indian Academy of Sciences (India)
... where signiﬁcant signals can be expected from the LHC experiments. The most sensitive LHC Higgs signatures are reviewed and the discovery year is estimated as a function of the Higgs mass. Finally, we give some ideas about: 'What might be known about the production and decays of a SM Higgs boson' after 10 years ...
90 - GeV Higgs boson in supersymmetric models
International Nuclear Information System (INIS)
Grzadkowski, B.; Kalinowski, J.; Pokorski, S.
1989-07-01
We discuss supersymmetric models with a hierarchy of vacuum expectation values of Higgs fields. These models predict one of the physical neutral Higgs bosons to have its mass very close to the Z-boson mass. Properties of such a 90-GeV Higgs boson are discussed. (author)
Searches for neutral Higgs bosons in extended models
Abdallah, J.; Blom, M.R.; Drees, J.; Palacios, J.; van der Pol, M.; Siebel, M.; van Dam, P.A.; Zupan, M.
2004-01-01
Searches for neutral Higgs bosons produced at LEP in association with Z bosons, in pairs and in the Yukawa process are presented in this paper. Higgs boson decays into b quarks, τ leptons, or other Higgs bosons are considered, giving rise to four-b, four-b+jets, six-b and four-τ final states, as
Un congreso de fisica estudia la composicion de las capas de la tierra
2003-01-01
"El Congreso de Internacional de Neutrinos, que ayer comenzo en el Jardin Botanico de Valencia, aborda, entre otros aspectos, la composicion y el perfil tomografico de las distintas capas de estratos del interior de la Tierra, segun informo a Efe el profesor Jose Furtado Valle" (1/2 page).
Fluxus (fayd). Indagine sui fondamenti della Metafisica e della Fisica di Avicenna
Lizzini, O.L.
2011-01-01
La teoria della causalità di Avicenna (Ibn Sīnā, m. 1037) è dominata dal concetto neoplatonico di flusso emanativo (in arabo fayḍ). Tutti i piani del sistema avicenniano ne sono interessati: quello metafisico, quello naturale, e quello intellettuale e quindi gnoseologico ed etico. Sulla base di
Higgs portal valleys, stability and inflation
Ballesteros, Guillermo
2015-01-01
The measured values of the Higgs and top quark masses imply that the Standard Model potential is very likely to be unstable at large Higgs values. This is particularly problematic during inflation, which sources large perturbations of the Higgs. The instability could be cured by a threshold effect induced by a scalar with a large vacuum expectation value and directly connected to the Standard Model through a Higgs portal coupling. However, we find that in a minimal model in which the scalar generates inflation, this mechanism does not stabilize the potential because the mass required for inflation is beyond the instability scale. This conclusion does not change if the Higgs has a direct weak coupling to the scalar curvature. On the other hand, if the potential is absolutely stable, successful inflation in agreement with current CMB data can occur along a valley of the potential with a Mexican hat profile. We revisit the stability conditions, independently of inflation, and clarify that the threshold effect ca...
Higgs EFT for 2HDM and beyond.
Bélusca-Maïto, Hermès; Falkowski, Adam; Fontes, Duarte; Romão, Jorge C; Silva, João P
2017-01-01
We discuss the validity of the Standard Model Effective Field Theory (SM EFT) as the low-energy effective theory for the two-Higgs-doublet Model (2HDM). Using the up-to-date Higgs signal strength measurements at the LHC, one can obtain a likelihood function for the Wilson coefficients of dimension-6 operators in the EFT Lagrangian. Given the matching between the 2HDM and the EFT, the constraints on the Wilson coefficients can be translated into constraints on the parameters of the 2HDM Lagrangian. We discuss under which conditions such a procedure correctly reproduces the true limits on the 2HDM. Finally, we employ the SM EFT to identify the pattern of the Higgs boson couplings that are needed to improve the fit to the current Higgs data. To this end, one needs, simultaneously, to increase the top Yukawa coupling, decrease the bottom Yukawa coupling, and induce a new contact interaction of the Higgs boson with gluons. We comment on how these modifications can be realized in the 2HDM extended by new colored particles.
New ideas for effective Higgs measurements
Energy Technology Data Exchange (ETDEWEB)
Brehmer, Johann
2017-07-26
An effective field theory provides a model-independent and phenomenologically powerful parametrisation of new physics in the Higgs sector. We analyse two aspects of this framework that are relevant for measurements of the Higgs properties during Run 2 of the LHC. First, the limited precision of the LHC analyses cannot guarantee a clear hierarchy between the experimental momentum transfer and the probed new physics scales, casting doubt on the validity of the effective model. By comparing a range of new physics scenarios to their dimension-six approximation, we analyse if an effective description of the Higgs sector is useful, where it breaks down, and how its validity can be improved. Second, we use information geometry to understand and optimise Higgs measurements at the LHC. Our novel approach is based on the Fisher information, which encodes the maximum precision with which theory parameters can be measured in an experiment. We develop an algorithm to calculate the Fisher information in LHC processes and compute the information on dimension-six operators in different Higgs signatures. We demonstrate how information geometry lets us improve event selections, determine the most powerful observables, and compare the power of modern multivariate techniques to that of traditional histogram-based analyses.
New ideas for effective Higgs measurements
International Nuclear Information System (INIS)
Brehmer, Johann
2017-01-01
An effective field theory provides a model-independent and phenomenologically powerful parametrisation of new physics in the Higgs sector. We analyse two aspects of this framework that are relevant for measurements of the Higgs properties during Run 2 of the LHC. First, the limited precision of the LHC analyses cannot guarantee a clear hierarchy between the experimental momentum transfer and the probed new physics scales, casting doubt on the validity of the effective model. By comparing a range of new physics scenarios to their dimension-six approximation, we analyse if an effective description of the Higgs sector is useful, where it breaks down, and how its validity can be improved. Second, we use information geometry to understand and optimise Higgs measurements at the LHC. Our novel approach is based on the Fisher information, which encodes the maximum precision with which theory parameters can be measured in an experiment. We develop an algorithm to calculate the Fisher information in LHC processes and compute the information on dimension-six operators in different Higgs signatures. We demonstrate how information geometry lets us improve event selections, determine the most powerful observables, and compare the power of modern multivariate techniques to that of traditional histogram-based analyses.
Direct search for Higgs boson in LHCb
Currat, C
2001-01-01
The LHCb detector is a forward one-arm spectrometer to precision measurements of CP violation in the B-meson systems. The motivation of the present work is to assess the potential of LHCb to observe a Standard Model (SM) Higgs signal. The recent results obtained at LEP give a hint of a SM Higgs boson with a mass mH = 115.0 +1.3 –0.9 GeV/c2 with a statistical significance of 2.9 standard deviations. Because of the high longitudinal boost encountered by the products in the pp collisions at LHC, a significant fraction (~30%) of light Higgs (mH = 115 GeV/c2) are produced in the LHCb acceptance 1.8 < h < 4.9. These facts potentially place LHCb in the race for the observation of the SM Higgs. Given a relatively low running luminosity of 2 x 1032 cm-2s-1- compared to the nominal 1034 cm-2s-1 at LHC and a limited geometrical acceptance, we have shown that the channels accessible to LHCb are H + WÂ± Z0 b`b + lÂ± X for Higgs masses in the range 100-130 GeV/c2. This work pioneered a setup for the pro...
The Higgs mass beyond the CMSSM
International Nuclear Information System (INIS)
Ellis, John; Luo, Feng; Olive, Keith A.; Sandick, Pearl
2013-01-01
The apparent discovery of a Higgs boson with mass ∝125 GeV has had a significant impact on the constrained minimal supersymmetric extension of the Standard Model (the CMSSM). Much of the low-mass parameter space in the CMSSM has been excluded by supersymmetric particle searches at the LHC as well as by the Higgs mass measurement and the emergent signal for B s →μ + μ - . Here, we consider the impact of these recent LHC results on several variants of the CMSSM with a primary focus on obtaining a Higgs mass of ∝125 GeV. In particular, we consider the one- and two-parameter extensions of the CMSSM with one or both of the Higgs masses set independently of the common sfermion mass, m 0 (the NUHM1,2). We also consider the one-parameter extension of the CMSSM in which the input universality scale M in is below the GUT scale (the sub-GUT CMSSM). Finally, we reconsider mSUGRA models with sub-GUT universality, which have the same number of parameters as the CMSSM. We find that when M in GUT large regions of parameter space open up where the relic density of neutralinos can successfully account for dark matter with a Higgs boson mass ∝125 GeV. Interestingly, we find that the preferred range of the A-term in sub-GUT mSUGRA models straddles that predicted by the simplest Polonyi model. (orig.)
Unitarity and predictiveness in new Higgs inflation
Fumagalli, Jacopo; Mooij, Sander; Postma, Marieke
2018-03-01
In new Higgs inflation the Higgs kinetic terms are non-minimally coupled to the Einstein tensor, allowing the Higgs field to play the role of the inflaton. The new interaction is non-renormalizable, and the model only describes physics below some cutoff scale. Even if the unknown UV physics does not affect the tree level inflaton potential significantly, it may still enter at loop level and modify the running of the Standard Model (SM) parameters. This is analogous to what happens in the original model for Higgs inflation. A key difference, though, is that in new Higgs inflation the inflationary predictions are sensitive to this running. Thus the boundary conditions at the EW scale as well as the unknown UV completion may leave a signature on the inflationary parameters. However, this dependence can be evaded if the kinetic terms of the SM fermions and gauge fields are non-minimally coupled to gravity as well. Our approach to determine the model's UV dependence and the connection between low and high scale physics can be used in any particle physics model of inflation.
Energy Technology Data Exchange (ETDEWEB)
Belusca-Maito, Hermes; Falkowski, Adam [CNRS, Univ. Paris-Sud, Universite Paris-Saclay, Laboratoire de Physique Theorique, Orsay (France); Fontes, Duarte; Romao, Jorge C.; Silva, Joao P. [Universidade de Lisboa, CFTP, Departamento de Fisica, Instituto Superior Tecnico, Lisbon (Portugal)
2017-03-15
We discuss the validity of the Standard Model Effective Field Theory (SM EFT) as the low-energy effective theory for the two-Higgs-doublet Model (2HDM). Using the up-to-date Higgs signal strength measurements at the LHC, one can obtain a likelihood function for the Wilson coefficients of dimension-6 operators in the EFT Lagrangian. Given the matching between the 2HDM and the EFT, the constraints on the Wilson coefficients can be translated into constraints on the parameters of the 2HDM Lagrangian. We discuss under which conditions such a procedure correctly reproduces the true limits on the 2HDM. Finally, we employ the SM EFT to identify the pattern of the Higgs boson couplings that are needed to improve the fit to the current Higgs data. To this end, one needs, simultaneously, to increase the top Yukawa coupling, decrease the bottom Yukawa coupling, and induce a new contact interaction of the Higgs boson with gluons. We comment on how these modifications can be realized in the 2HDM extended by new colored particles. (orig.)
Gaugephobic Higgs Signals at the LHC
Galloway, Jamison; McRaven, John; Terning, John
2009-01-01
The Gaugephobic Higgs model provides an interpolation between three different models of electroweak symmetry breaking: Higgsless models, Randall-Sundrum models, and the Standard Model. At parameter points between the extremes, Standard Model Higgs signals are present at reduced rates, and Higgsless Kaluza-Klein excitations are present with shifted masses and couplings, as well as signals from exotic quarks necessary to protect the Zbb coupling. Using a new implementation of the model in SHERPA, we show the LHC signals which differentiate the generic Gaugephobic Higgs model from its limiting cases. These are all signals involving a Higgs coupling to a Kaluza-Klein gauge boson or quark. We identify the clean signal $p p \\to W^(i) \\to W H$ mediated by a Kaluza-Klein W, which can be present at large rates and is enhanced for even Kaluza-Klein numbers. Due to the very hard lepton coming from the W decay, this signature has little background, and provides a better discovery channel for the Higgs than any of the Sta...
Interference contributions to gluon initiated heavy Higgs production in the Two-Higgs-Doublet Model
International Nuclear Information System (INIS)
Greiner, Nicolas
2016-03-01
We discuss the production of a heavy neutral Higgs boson of a CP-conserving Two-Higgs-Doublet Model in gluon fusion and its decay into a four-fermion final state, gg(→VV)→e + e - π + π - /e + e - ν l anti ν l . We investigate the interference contributions to invariant mass distributions of the four-fermion final state and other relevant kinematical observables. The relative importance of the different contributions is quantified for the process in the on-shell approximation, gg→ZZ. We show that interferences of the heavy Higgs with the light Higgs boson and background contributions are essential for a correct description of the differential cross section. Even though they contribute below O(10%) to those heavy Higgs signal cross sections, to which the experiments at the Large Hadron Collider were sensitive in its first run, we find that they are sizeable in certain regions of the parameter space that are relevant for future heavy Higgs boson searches. In fact, the interference contributions can significantly enhance the experimental sensitivity to the heavy Higgs boson.
Gauge boson/Higgs boson unification: The Higgs bosons as superpartners of massive gauge bosons
International Nuclear Information System (INIS)
Fayet, P.
1984-01-01
We show how one can use massive gauge superfields to describe, simultaneously, gauge bosons (Wsup(+-), Z, ...) and Higgs bosons (wsup(+-), z, ...) together with their spin-1/2 partners (pairs of winos, zinos, ...), despite their different electroweak properties. This provides a manifestly supersymmetric formulation of spontaneously broken supersymmetric gauge theories, and makes explicit the relations between massive gauge bosons and Higgs bosons. It raises, however, the following question: if the gauge bosons Wsup(+-) and Z and the Higgs bosons wsup(+-) and z are related by supersymmetry, how it is possible that the former couple to leptons and quarks proportionately to g or g', and the latter proportionately to gsub(F)sup(1/2) m (fermions). The paradox is solved as follows: when the Higgs bosons are described by massive gauge superfields, the lagrangian density is non-polynomial and field redefinitions have to be performed, in particular: lepton or quark field -> lepton or quark field + (approx.= Gsub(F)sup(1/2) Higgs field) (lepton or quark field). They automatically regenerate, from the lepton and quark supersymmetric mass terms, the correct Yukawa couplings of Higgs bosons proportional to fermion masses. We also apply this method to the case in which an extra U(1) group is gauged, the standard Higgs boson h 0 being then the superpartner of the new neutral gauge boson U. (orig.)
Large Higgs energy region in Higgs associated top pair production at the Linear Collider
International Nuclear Information System (INIS)
Farrell, Cailin; Hoang, Andre H.
2005-01-01
The process e + e - →ttH is considered in the kinematic end point region where the Higgs energy is close to its maximal energy. In perturbative QCD, using the loop expansion, the amplitudes are plagued by Coulomb singularities that need to be resummed. We show that the QCD dynamics in this end point region is governed by nonrelativistic heavy quarkonium dynamics, and we use a nonrelativistic effective theory to compute the Higgs energy distribution at leading and next-to-leading-logarithmic approximation in the nonrelativistic expansion. Updated numbers for the total cross section including the summations in the Higgs energy end point region are presented
Beyond the standard Higgs after the 125 GeV Higgs discovery.
Grojean, C
2015-01-13
An elementary weakly coupled and solitary Higgs boson allows one to extend the validity of the Standard Model up to very high energy, maybe as high as the Planck scale. Nonetheless, this scenario fails to fill the universe with dark matter and does not explain the matter-antimatter asymmetry. However, amending the Standard Model tends to destabilize the weak scale by large quantum corrections to the Higgs potential. New degrees of freedom, new forces, new organizing principles are required to provide a consistent and natural description of physics beyond the standard Higgs.
Higgs boson pair production at the photon linear collider in the two Higgs doublet model
International Nuclear Information System (INIS)
Asakawa, Eri; Harada, Daisuke; Okada, Yasuhiro; Kanemura, Shinya; Tsumura, Koji
2009-02-01
We calculate the cross section of the lightest Higgs boson pair production at the Photon Linear Collider in the two Higgs doublet model. We focus on the scenario in which the lightest Higgs boson has the standard model like couplings to gauge bosons. We take into account the one-loop correction to the hhh coupling as well as additional one-loop diagrams due to charged bosons to the γγ → hh helicity amplitudes. We discuss the impact of these corrections on the hhh coupling measurement at the Photon Linear Collider. (author)
Search for a lighter Higgs boson in Two Higgs Doublet Models
Energy Technology Data Exchange (ETDEWEB)
Cacciapaglia, Giacomo; Deandrea, Aldo; Gascon-Shotkin, Suzanne; Corre, Solène Le; Lethuillier, Morgan [University Lyon, Université Claude Bernard Lyon 1, CNRS/IN2P3, UMR5822 IPNL,4, rue E. Fermi, Villeurbanne, F-69622 (France); Tao, Junquan [Institute High Energy Physics, Chinese Academy of Sciences,P.O. Box 918, Beijing, 100049 (China)
2016-12-15
We consider present constraints on Two Higgs Doublet Models, both from the LHC at Run 1 and from other sources in order to explore the possibility of constraining a neutral scalar or pseudo-scalar particle lighter than the 125 GeV Higgs boson. Such a lighter particle is not yet completely excluded by present data. We show with a simplified analysis that some new constraints could be obtained at the LHC if such a search is performed by the experimental collaborations, which we therefore encourage to continue carrying out light diphoton resonance searches at √s=13 TeV in the context of Two Higgs Doublet Models.
Studies of the SM Higgs boson and searches for BSM Higgs bosons with the ATLAS Detector
AUTHOR|(INSPIRE)INSPIRE-00182253; The ATLAS collaboration
2016-01-01
The ATLAS collaboration has searched for the Standard Model Higgs Boson in the first LHC Run-2 data using 3.2 $fb^{-1}$ at 13 TeV. Results are presented in terms of central value and limits on the total cross-section in the 4l and $\\gamma\\gamma$ channels. Several "Beyond Standard Model" theories predict the existence of additional heavy Higgs particles or di-Higgs resonances. Searches are conducted using the $\\gamma\\gamma$, ZZ, WW and fermionic decay channels, and cover a large range of masses for the hypothetical resonances.
Higgs particles in the standard model and supersymmetric theories
International Nuclear Information System (INIS)
Muehlleitner, M.M.
2000-08-01
This thesis presents a theoretical analysis of the properties of the Higgs bosons in the standard model (SM) and the minimal supersymmetric extension (MSSM), which can be investigated at the LHC and e + e - linear colliders. The final goal is the reconstruction of the Higgs potential and thus the verification of the Higgs mechanism. MSSM Higgs boson production processes at future γγ colliders are calculated in several decay channels. Heavy scalar and pseudoscalar Higgs bosons can be discovered in the bb final state in the investigated mass range 200 to 800 GeV for moderate and large values of tanβ. The τ + τ - channel provides a heavy Higgs boson discovery potential for large values of tanβ. Several mechanisms that can be exploited at e + e - linear colliders for the measurement of the lifetime of a SM Higgs boson in the intermediate mass range are analysed. In the WW mode, the lifetime of Higgs scalars with masses below ∝160 GeV can be determined with an error less than 10%. The reconstruction of the Higgs potential requires the measurement of the Higgs self-couplings. The SM and MSSM trilinear Higgs self-couplings are accessible in double and triple Higgs production. A theoretical analysis is presented in the relevant channels at the LHC and e + e - linear colliders. For high luminosities, the SM trilinear Higgs self-coupling can be measured with an accuracy of 20% at a 500 GeV e + e - linear collider. The MSSM coupling among three light Higgs bosons has to be extracted from continuum production. The other trilinear Higgs couplings are measurable in a restricted range of the MSSM parameter space. At the LHC, the Hhh coupling can be probed in resonant decays. (orig.)
Turning on gravity with the Higgs mechanism
International Nuclear Information System (INIS)
Alexander, Stephon; Barrow, John D; Magueijo, João
2016-01-01
We investigate how a Higgs mechanism could be responsible for the emergence of gravity in extensions of Einstein theory, with a suitable low energy limit. In this scenario, at high energies, symmetry restoration could ‘turn off’ gravity, with dramatic implications for cosmology and quantum gravity. The sense in which gravity is muted depends on the details of the implementation. In the most extreme case gravity’s dynamical degrees of freedom would only be unleashed after the Higgs field acquires a non-trivial vacuum expectation value, with gravity reduced to a topological field theory in the symmetric phase. We might also identify the Higgs and the Brans–Dicke fields in such a way that in the unbroken phase Newton’s constant vanishes, decoupling matter and gravity. We discuss the broad implications of these scenarios. (letter)
Higgs to bb in the VBF channel
CMS Collaboration
2013-01-01
A search for the standard model Higgs boson in the vector boson fusion production channel with decay to bottom quarks is reported. A data sample comprising 19.0~fb$^{-1}$ of proton-proton collisions at $\\sqrt{s}=8$~TeV collected during the 2012 running period has been analyzed and 95\\% Confidence Level upper limits are derived for five mass points from 115 to 135 GeV. At a Higgs boson mass of 125~GeV the observed limit is 3.6 while the expected limit is 3.0 times the standard model prediction. For a 125 GeV Higgs boson signal the fitted signal strength is $\\mu=\\sigma/\\sigma_{\\rm SM}=0.7\\pm1.4$.
Effective field theory analysis of Higgs naturalness
Energy Technology Data Exchange (ETDEWEB)
Bar-Shalom, Shaouly [Technion-Israel Inst. of Tech., Haifa (Israel); Soni, Amarjit [Brookhaven National Lab. (BNL), Upton, NY (United States); Wudka, Jose [Univ. of California, Riverside, CA (United States)
2015-07-20
Assuming the presence of physics beyond the Standard Model ( SM) with a characteristic scale M ~ O (10) TeV, we investigate the naturalness of the Higgs sector at scales below M using an effective field theory (EFT) approach. We obtain the leading 1 -loop EFT contributions to the Higgs mass with a Wilsonian-like hard cutoff, and determine t he constraints on the corresponding operator coefficients for these effects to alleviate the little hierarchy problem up to the scale of the effective action Λ < M , a condition we denote by “EFT-naturalness”. We also determine the types of physics that can lead to EFT-naturalness and show that these types of new physics are best probed in vector-boson and multiple-Higgs production. The current experimental constraints on these coefficients are also discussed.
Higgs inflation at the critical point
Bezrukov, Fedor
2014-01-01
Higgs inflation can occur if the Standard Model (SM) is a self-consistent effective field theory up to inflationary scale. This leads to a lower bound on the Higgs boson mass, $M_h \\geq M_{\\text{crit}}$. If $M_h$ is more than a few hundreds of MeV above the critical value, the Higgs inflation predicts the universal values of inflationary indexes, $r\\simeq 0.003$ and $n_s\\simeq 0.97$, independently on the Standard Model parameters. We show that in the vicinity of the critical point $M_{\\text{crit}}$ the inflationary indexes acquire an essential dependence on the mass of the top quark $m_t$ and $M_h$. In particular, the amplitude of the gravitational waves can exceed considerably the universal value.
Higgs Decay into Two Photons, Revisited
Gastmans, R; Wu, Tai Tsun
2011-01-01
The one-loop calculation of the amplitude for the Higgs decay H-->\\gamma\\gamma\\ due to virtual W's in the unitary gauge is presented. As the Higgs does not directly couple to the massless photons, the one-loop amplitude is finite. The calculation is performed in a straightforward way, without encountering divergences. In particular, artifacts like dimensional regularization are avoided. This is achieved by judiciously routing the external momenta through the loop and by combining the integrands of the amplitudes before carrying out the integration over the loop momentum. The present result satisfies the decoupling theorem for infinite Higgs mass, and is thus different from the earlier results obtained in the \\xi=1 gauge using dimensional regularization. The difference between the results is traced to the use of dimensional regularization.
Acquiring a taste for the Higgs boson
Caroline Duc
2012-01-01
Before CERN's scientists had even announced the discovery of the Higgs boson, others were already attributing some interesting characteristics to it: flavoursome, sparkling and liquid... The artisan brewery Hopfenstark in Quebec launched its new "Higgs boson" beer in November 2010. Ever since, it has been intriguing enthusiasts with its unique taste explosion. The boson was a source of inspiration for brewer Frédéric Cormier, the Hopfenstark brewery's owner, who is a big fan of science programmes. "I returned from a trip to Europe in 2010 with the idea for a new beer that would be unlike any other," he explains. "I was always reading and hearing about CERN's particle accelerator in the media, so I did some research on the famous Higgs boson and decided to give my new creation the same name." For Frédéric Cormier, it's important that the names of his beers refle...
Searching for displaced Higgs boson decays
Csáki, Csaba; Kuflik, Eric; Lombardo, Salvator; Slone, Oren
2015-10-01
We study a simplified model of the Standard Model (SM) Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs boson decays below 10 cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at √{s }=13 TeV . With 20 fb-1 of data, we find that Higgs branching ratios down to 2 ×1 0-4 can be probed for centimeter decay lengths.
Higgs boson from an extended symmetry
International Nuclear Information System (INIS)
Barbieri, Riccardo; Bellazzini, Brando; Rychkov, Vyacheslav S.; Varagnolo, Alvise
2007-01-01
The variety of ideas put forward in the context of a composite picture for the Higgs boson calls for a simple and effective description of the related phenomenology. Such a description is given here by means of a minimal model and is explicitly applied to the example of a Higgs-top sector from an SO(5) symmetry. We discuss the spectrum, the electroweak precision tests, B-physics, and naturalness. We show the difficulty in complying with the different constraints. The extended gauge sector relative to the standard SU(2)xU(1), if there is any, has little or no impact on these considerations. We also discuss the relation of the minimal model with its 'little Higgs' or holographic extensions based on the same symmetry
CMS standard model Higgs boson results
Directory of Open Access Journals (Sweden)
Garcia-Abia Pablo
2013-11-01
Full Text Available In July 2012 CMS announced the discovery of a new boson with properties resembling those of the long-sought Higgs boson. The analysis of the proton-proton collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.1 fb−1 at √s = 7 TeV and 19.6 fb−1 at √s = 8 TeV, confirm the Higgs-like nature of the new boson, with a signal strength associated with vector bosons and fermions consistent with the expectations for a standard model (SM Higgs boson, and spin-parity clearly favouring the scalar nature of the new boson. In this note I review the updated results of the CMS experiment.
Unveiling the Higgs mechanism to students
International Nuclear Information System (INIS)
Organtini, Giovanni
2012-01-01
In this paper we outline a lecture given to undergraduate students to explain why physicists are so interested in the Higgs boson. The lecture was conceived for students not yet familiar with advanced physics and is suitable for those studying several other disciplines. The Higgs mechanism is introduced through semi-classical arguments mimicking basic field-theory concepts, assuming the validity of a symmetry principle in the expression of the energy of particles in a classical field. The lecture is divided into two parts. The first, suitable even for high-school students, shows how the mass of a particle results from a dynamical effect caused by interaction between a massless particle and a field (as in the Higgs mechanism). The audience for the second, much more technical part consists mainly of teachers and university students from disciplines other than physics. (paper)
A flavor sector for the composite Higgs
Energy Technology Data Exchange (ETDEWEB)
Vecchi, Luca, E-mail: vecchi@lanl.gov
2013-11-25
We discuss flavor violation in large N Composite Higgs models. We focus on scenarios in which the masses of the Standard Model fermions are controlled by hierarchical mixing parameters, as in models of Partial Compositeness. We argue that a separation of scales between flavor and Higgs dynamics can be employed to parametrically suppress dipole and penguin operators, and thus effectively remove the experimental constraints arising from the lepton sector and the neutron EDM. The dominant source of flavor violation beyond the Standard Model is therefore controlled by 4-fermion operators, whose Wilson coefficients can be made compatible with data provided the Higgs dynamics approaches a “walking” regime in the IR. Models consistent with all flavor and electroweak data can be obtained with a new physics scale within the reach of the LHC. Explicit scenarios may be realized in a 5D framework, the new key ingredient being the introduction of flavor branes where the wave functions of the bulk fermions end.
Gauge-Higgs unification in higher dimensions
International Nuclear Information System (INIS)
Hall, Lawrence; Nomura, Yasunori; Smith, David
2002-01-01
The electroweak Higgs doublets are identified as components of a vector multiplet in a higher-dimensional supersymmetric field theory. We construct a minimal model in 6D where the electroweak SU(2)xU(1) gauge group is extended to SU(3), and unified 6D models with the unified SU(5) gauge symmetry extended to SU(6). In these realistic theories the extended gauge group is broken by orbifold boundary conditions, leaving Higgs doublet zero modes which have Yukawa couplings to quarks and leptons on the orbifold fixed points. In one SU(6) model the weak mixing angle receives power law corrections, while in another the fixed point structure forbids such corrections. A 5D model is also constructed in which the Higgs doublet contains the fifth component of the gauge field. In this case Yukawa couplings are introduced as nonlocal operators involving the Wilson line of this gauge field
Stabilizing the Higgs potential with a Z′
International Nuclear Information System (INIS)
Di Chiara, Stefano; Keus, Venus; Lebedev, Oleg
2015-01-01
Current data point toward metastability of the electroweak vacuum within the Standard Model. We study the possibility of stabilizing the Higgs potential in U(1) extensions thereof. A generic Z′ boson improves stability of the scalar potential in two ways: it increases the Higgs self-coupling, due to a positive contribution to the beta-function of the latter, and it decreases the top quark Yukawa coupling, which again has a stabilizing effect. We determine the range of U(1) charges which leads to a stable electroweak vacuum. In certain classes of models, such stabilization is possible even if the Z′ does not couple to the Higgs and is due entirely to the reduction of the top Yukawa coupling. We also study the effect of the kinetic mixing between the extra U(1) and hypercharge gauge fields
Pseudo-Observables in Higgs decays
CERN. Geneva
2015-01-01
In view of future high-statistics data, it is useful to define a framework for precise determinations of the properties of the Higgs particle valid in generic extensions of the Standard Model. For Higgs decays, this goal can be achieved with a limited set of "Pseudo-Observables" (PO). The PO provides a systematic generalization of the "kappa-framework" so far adopted by the LHC experiments and provide a useful bridge between data and theory predictions. I discuss how the PO are defined, with particular attention to the h->4f decays, and how they can be used to test various dynamical and symmetry hypotheses about the Higgs sector. The relation between PO and EFT couplings is also discussed.
Electroweak symmetry breaking: Higgs/whatever
International Nuclear Information System (INIS)
Chanowitz, M.S.
1989-01-01
In the first of these two lectures the Higgs mechanism is reviewed in its most general form, which does not necessarily require the existence of Higgs bosons. The general consequences of the hypothesis that electroweak symmetry breaking is due to the Higgs mechanism are deduced just from gauge invariance and unitarity. In the second lecture the general properties are illustrated with three specific models: the Weinberg-Salam model, its minimal supersymmetric extension, and technicolor. The second lecture concludes with a discussion of the experiment signals for strong WW scattering, whose presence or absence will allow us to determine whether the symmetry breaking sector lies above or below 1 TeV. 57 refs
New signatures of flavor violating Higgs couplings
Energy Technology Data Exchange (ETDEWEB)
Buschmann, Malte; Kopp, Joachim; Liu, Jia; Wang, Xiao-Ping [PRISMA Cluster of Excellence and Mainz Institute for Theoretical Physics,Johannes Gutenberg University, 55099 Mainz (Germany)
2016-06-24
We explore several novel LHC signatures arising from quark or lepton flavor violating couplings in the Higgs sector, and we constrain such couplings using LHC data. Since the largest signals are possible in channels involving top quarks or tau leptons, we consider in particular the following flavor violating processes: (1) pp→thh (top plus di-Higgs final state) arising from a dimension six coupling of up-type quarks to three insertions of the Higgs field. We develop a search strategy for this final state and demonstrate that detection is possible at the high luminosity LHC if flavor violating top-up-Higgs couplings are not too far below the current limit. (2) pp→tH{sup 0}, where H{sup 0} is the heavy neutral CP-even Higgs boson in a two Higgs doublet model (2HDM). We consider the decay channels H{sup 0}→tu,WW,ZZ,hh and use existing LHC data to constrain the first three of them. For the fourth, we adapt our search for the thh final state, and we demonstrate that in large regions of the parameter space, it is superior to other searches, including searches for flavor violating top quark decays (t→hq). (3) H{sup 0}→τμ, again in the context of a 2HDM. This channel is particularly well motivated by the recent CMS excess in h→τμ, and we use the data from this search to constrain the properties of H{sup 0}.
Higgs boson mass and new physics
Energy Technology Data Exchange (ETDEWEB)
Bezrukov, Fedor [Connecticut Univ., Storrs, CT (United States). Dept. of Physics; Brookhaven National Lab., Upton, NY (United States). RIKEN-BNL Research Center; Kalmykov, Mikhail Yu.; Kniehl, Bernd A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Shaposhnikov, Mikhail [Ecole Polytechnique Federale de Lausanne (Switzerland). Inst. de Theorie des Phenomenes Physiques
2012-05-15
We discuss the lower Higgs boson mass bounds which come from the absolute stability of the Standard Model (SM) vacuum and from the Higgs inflation, as well as the prediction of the Higgs boson mass coming from asymptotic safety of the SM. We account for the 3-loop renormalization group evolution of the couplings of the Standard Model and for a part of two-loop corrections that involve the QCD coupling {alpha}{sub s} to initial conditions for their running. This is one step above the current state of the art procedure (''one-loop matching-two-loop running''). This results in reduction of the theoretical uncertainties in the Higgs boson mass bounds and predictions, associated with the Standard Model physics, to 1-2 GeV. We find that with the account of existing experimental uncertainties in the mass of the top quark and {alpha}{sub s} (taken at 2{sigma} level) the bound reads M{sub H} {>=} M{sub min} (equality corresponds to the asymptotic safety prediction), where M{sub min}=129{+-}6 GeV. We argue that the discovery of the SM Higgs boson in this range would be in agreement with the hypothesis of the absence of new energy scales between the Fermi and Planck scales, whereas the coincidence of M{sub H} with M{sub min} would suggest that the electroweak scale is determined by Planck physics. In order to clarify the relation between the Fermi and Planck scale a construction of an electron-positron or muon collider with a center of mass energy {proportional_to}200+200 GeV (Higgs and t-quark factory) would be needed.
Higgs boson mass and new physics
International Nuclear Information System (INIS)
Bezrukov, Fedor; Brookhaven National Lab., Upton, NY; Kalmykov, Mikhail Yu.; Kniehl, Bernd A.; Shaposhnikov, Mikhail
2012-05-01
We discuss the lower Higgs boson mass bounds which come from the absolute stability of the Standard Model (SM) vacuum and from the Higgs inflation, as well as the prediction of the Higgs boson mass coming from asymptotic safety of the SM. We account for the 3-loop renormalization group evolution of the couplings of the Standard Model and for a part of two-loop corrections that involve the QCD coupling α s to initial conditions for their running. This is one step above the current state of the art procedure (''one-loop matching-two-loop running''). This results in reduction of the theoretical uncertainties in the Higgs boson mass bounds and predictions, associated with the Standard Model physics, to 1-2 GeV. We find that with the account of existing experimental uncertainties in the mass of the top quark and α s (taken at 2σ level) the bound reads M H ≥ M min (equality corresponds to the asymptotic safety prediction), where M min =129±6 GeV. We argue that the discovery of the SM Higgs boson in this range would be in agreement with the hypothesis of the absence of new energy scales between the Fermi and Planck scales, whereas the coincidence of M H with M min would suggest that the electroweak scale is determined by Planck physics. In order to clarify the relation between the Fermi and Planck scale a construction of an electron-positron or muon collider with a center of mass energy ∝200+200 GeV (Higgs and t-quark factory) would be needed.
Large mass of the littlest Higgs boson
International Nuclear Information System (INIS)
Bazzocchi, F.; Fabbrichesi, M.; Piai, M.
2005-01-01
We study the exact (one-loop) effective potential of the littlest Higgs model and determine the dependence of physical quantities, such as the vacuum expectation value v W and mass m h of the Higgs boson, on the fundamental parameters of the Lagrangian--masses, couplings of new states, the fundamental scale f of the sigma model, and the coefficients of operators quadratically sensitive to the cutoff of the theory. On the one hand, we show that it is possible to have the electroweak ground state and a relatively large cutoff Λ=4πf with f in the 2 TeV range without requiring unnaturally small coefficients for quadratically divergent quantities, and with only moderate cancellations between the contribution of different sectors to the effective potential of the Higgs. On the other hand, this cannot be achieved while at the same time keeping m h close to its current lower bound of 114.4 GeV. The natural expectation for m h is O(f), mainly because of large logarithmically divergent contributions to the effective potential of the top-quark sector. Even a fine-tuning at the level of O(10 -2 ) in the coefficients of the quadratic divergences is not enough to produce small physical Higgs masses, and the natural expectation is in the 800 GeV range for f∼2 TeV. We conclude that the littlest Higgs model is a solution of the little hierarchy problem, in the sense that it stabilizes the electroweak symmetry breaking scale to be a factor of 100 less than the cutoff of the theory, but this requires a quite large physical mass for the Higgs, and hence precision electroweak studies should be redone accordingly. We also study finite temperature corrections. The first order electroweak phase transition is no stronger than in the standard model. A second phase transition (nonrestoration of symmetry at high temperature) depends strongly on the logarithmic terms in the potential
Maximal CP violation via Higgs-boson exchange
International Nuclear Information System (INIS)
Lavoura, L.
1992-01-01
The unitarity of the mixing matrix of the charged Higgs bosons, and the orthogonality of the mixing matrix of the neutral Higgs bosons, are used to derive upper bounds on the values of general CP-violating expressions. The bounds are independent of the total number of Higgs fields in any specific model. They allow is to relax the usual assumption of only one Higgs boson being light. It is natural that the CP violation in the exchange of neutral Higgs bosons between bottom quarks be particularly large
CP Studies and Non-Standard Higgs Physics
DEFF Research Database (Denmark)
Kraml, S.; Accomando, E.; G. Akeroyd, A.
2006-01-01
There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state......, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories...
Natural Higgs mass in supersymmetry from nondecoupling effects.
Lu, Xiaochuan; Murayama, Hitoshi; Ruderman, Joshua T; Tobioka, Kohsaku
2014-05-16
The Higgs mass implies fine-tuning for minimal theories of weak-scale supersymmetry (SUSY). Nondecoupling effects can boost the Higgs mass when new states interact with the Higgs boson, but new sources of SUSY breaking that accompany such extensions threaten naturalness. We show that two singlets with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. We explore the modified Higgs phenomenology of this scenario, which we call the "Dirac next-to-minimal supersymmetric standard model."
Searches for non-Standard Model Higgs bosons
Dumitriu, Ana Elena; The ATLAS collaboration
2018-01-01
This presentation focuses on the Searches for non-Standard Model Higgs bosons using 36.1 fb of data collected by the ATLAS experiment. There are several theoretical models with an extended Higgs sector considered: 2 Higgs Doublet Models (2HDM), Supersymmetry (SUSY), which brings along super-partners of the SM particles (+ The Minimal Supersymmetric Standard Model (MSSM), whose Higgs sector is equivalent to the one of a constrained 2HDM of type II and the next-to MSSM (NMSSM)), General searches and Invisible decaying Higgs boson.
Standard model Higgs boson-inflaton and dark matter
International Nuclear Information System (INIS)
Clark, T. E.; Liu Boyang; Love, S. T.; Veldhuis, T. ter
2009-01-01
The standard model Higgs boson can serve as the inflaton field of slow roll inflationary models provided it exhibits a large nonminimal coupling with the gravitational scalar curvature. The Higgs boson self interactions and its couplings with a standard model singlet scalar serving as the source of dark matter are then subject to cosmological constraints. These bounds, which can be more stringent than those arising from vacuum stability and perturbative triviality alone, still allow values for the Higgs boson mass which should be accessible at the LHC. As the Higgs boson coupling to the dark matter strengthens, lower values of the Higgs boson mass consistent with the cosmological data are allowed.
Towards a unified picture for gauge and Higgs fields
International Nuclear Information System (INIS)
Mecklenburg, W.
1981-01-01
A scheme for a geometrical unification of gauge and Higgs fields, previously given for SU 2 , is generalized to include arbitrary semisimple gauge groups. Gauge and physical Higgs fields appear as different components of the same tensor in a high dimensional manifold, the higher dimensions being comprised by the group coordinates. Their respective inhomogeneous transformation behaviour is derived from the same principle. The number of Higgs fields is restricted. The form of the Higgs potential is fixed and the mass of the Higgs particle is predicted in terms of the vector boson mass. (author)
Search for Higgs bosons beyond the Standard Model
Directory of Open Access Journals (Sweden)
Mankel Rainer
2015-01-01
Full Text Available While the existence of a Higgs boson with a mass near 125 GeV has been clearly established, the detailed structure of the entire Higgs sector is yet unclear. Beyond the standard model interpretation, various scenarios for extended Higgs sectors are being considered. Such options include the minimal and next-to-minimal supersymmetric extensions (MSSM and NMSSM of the standard model, more generic Two-Higgs Doublet models (2HDM, as well as truly exotic Higgs bosons decaying e.g. into totally invisible final states. This article presents recent results from the CMS experiment.
Higgs enhancement for the dark matter relic density
Harz, Julia; Petraki, Kalliopi
2018-04-01
We consider the long-range effect of the Higgs on the density of thermal-relic dark matter. While the electroweak gauge boson and gluon exchange have been previously studied, the Higgs is typically thought to mediate only contact interactions. We show that the Sommerfeld enhancement due to a 125 GeV Higgs can deplete TeV-scale dark matter significantly and describe how the interplay between the Higgs and other mediators influences this effect. We discuss the importance of the Higgs enhancement in the minimal supersymmetric standard model and its implications for experiments.
Search for Charged Higgs Bosons at LEP
Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, Mohammad Azizur; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.
2003-01-01
A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at centre-of-mass energies between 189 and 209GeV, corresponding to an integrated luminosity of 629.4/pb. Decays into a charm and a strange quark or into a tau lepton and its neutrino are considered. No significant excess is observed and lower limits on the mass of the charged Higgs boson are derived at the 95% confidence level. They vary from 76.5 to 82.7GeV, as a function of the H->tv branching ratio.
CMS latest results on Higgs measurements
CERN. Geneva
2014-01-01
Since the discovery of a Higgs boson by the CMS and ATLAS Collaborations in 2012, physicists at the LHC have been making intense efforts to measure this new particle’s properties. Last week, at the 37th International Conference on High Energy Physics, the CMS Collaboration has presented a broad set of results from new studies of the Higgs boson. They are based on the full Run 1 data from pp collisions at centre-of-mass energies of 7 and 8 TeV. The analyses include the final calibration and alignment constants and contains about 25 fb−1 of data. These new results will be summarized here.
Supersymmetric Higgs boson production in Z decays
International Nuclear Information System (INIS)
Gamberini, G.; Giudice, G.F.; Ridolfi, G.
1987-01-01
The problem of distinguishing between the standard model and the supersymmetric Higgs bosons is considered in the context of Z 0 decays. We find that, for some choices of the parameters, the branching ratio for Z 0 → H 0 γ is strongly enhanced by the exchange of supersymmetric fermions as virtual particles. This makes the study of this process at LEP very interesting, since other Z 0 branching modes into Higgs bosons, such as Z 0 → H 0 μ + μ - , are not so clearly modified by supersymmetry. (orig.)
Cosmological implications of Higgs near-criticality.
Espinosa, J R
2018-03-06
The Standard Model electroweak (EW) vacuum, in the absence of new physics below the Planck scale, lies very close to the boundary between stability and metastability, with the last option being the most probable. Several cosmological implications of this so-called 'near-criticality' are discussed. In the metastable vacuum case, the main challenges that the survival of the EW vacuum faces during the evolution of the Universe are analysed. In the stable vacuum case, the possibility of implementing Higgs inflation is critically examined.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).
Composite (Goldstone) Higgs Dynamics on the Lattice
DEFF Research Database (Denmark)
Arthur, Rudy; Drach, Vincent; Hansen, Martin Rasmus Lundquist
2014-01-01
We study the meson spectrum of the SU(2) gauge theory with two Wilson fermions in the fundamental representation. The theory unifies both Technicolor and composite Goldstone Boson Higgs models of electroweak symmetry breaking. We have calculated the masses of the lightest spin one vector and axial...... for accelerator experiments, whereas the scalar meson will mix with a pGB of the theory and produce two scalar states. The lighter of the states is the 125 GeV Higgs boson, and the heavier would be a new yet unobserved scalar state....
Inverse Higgs effect in nonlinear realizations
International Nuclear Information System (INIS)
Ivanov, E.A.; Ogievetskij, V.I.
1975-01-01
In theories with nonlinearly realized symmetry it is possible in a number of cases to eliminate some initial Goldstone and gauge fields by means of putting appropriate Cartan forms equal to zero. This is called the inverse Higgs phenomenon. We give a general treatment of the inverse Higgs phenomenon for gauge and space-time symmetries and consider four instructive examples which are the elimination of unessential gauge fields in chiral symmetry and in non-linearly realized supersymmetry and also the elimination of unessential Goldstone fields in the spontaneously broken conformal and projective symmetries
Effective Higgs theories in supersymmetric grand unification
Energy Technology Data Exchange (ETDEWEB)
Zheng, Sibo [Chongqing University, Department of Physics, Chongqing (China)
2017-09-15
The effective Higgs theories at the TeV scale in supersymmetric SU(5) grand unification models are systematically derived. Restricted to extensions on 5{sub H} containing the Higgs sector we show that only two types of real (vector-like) models and one type of chiral model are found to be consistent with perturbative grand unification. While the chiral model has been excluded by the LHC data, the fate of perturbative unification will be uniquely determined by the two classes of vector-like models. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Burda, Philipp [Racah Institute of Physics, Hebrew University,Jerusalem 91904 (Israel); Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Moss, Ian G. [School of Mathematics and Statistics, Newcastle University,Newcastle Upon Tyne, NE1 7RU (United Kingdom)
2016-06-06
We have recently suggested that tiny black holes can act as nucleation seeds for the decay of the metastable Higgs vacuum. Previous results applied only to the nucleation of thin-wall bubbles, and covered a very small region of parameter space. This paper considers bubbles of arbitrary profile and reaches the same conclusion: black holes seed rapid vacuum decay. Seeded and unseeded nucleation rates are compared, and the gravitational back reaction of the bubbles is taken into account. The evolution of the bubble interior is described for the unseeded nucleation. Results are presented for the renormalisation group improved Standard Model Higgs potential, and a simple effective model representing new physics.
International Nuclear Information System (INIS)
Burda, Philipp; Gregory, Ruth; Moss, Ian G.
2016-01-01
We have recently suggested that tiny black holes can act as nucleation seeds for the decay of the metastable Higgs vacuum. Previous results applied only to the nucleation of thin-wall bubbles, and covered a very small region of parameter space. This paper considers bubbles of arbitrary profile and reaches the same conclusion: black holes seed rapid vacuum decay. Seeded and unseeded nucleation rates are compared, and the gravitational back reaction of the bubbles is taken into account. The evolution of the bubble interior is described for the unseeded nucleation. Results are presented for the renormalisation group improved Standard Model Higgs potential, and a simple effective model representing new physics.
A Geometrical View of Higgs Effective Theory
CERN. Geneva
2016-01-01
A geometric formulation of Higgs Effective Field Theory (HEFT) is presented. Experimental observables are given in terms of geometric invariants of the scalar sigma model sector such as the curvature of the scalar field manifold M. We show how the curvature can be measured experimentally via Higgs cross-sections, W_L scattering, and the S parameter. The one-loop action of HEFT is given in terms of geometric invariants of M. The distinction between the Standard Model (SM) and HEFT is whether M is flat or curved, with the curvature a signal of the scale of new physics.
Norjoharuddeen, Nurfikri; The ATLAS collaboration
2017-01-01
We present updates of W, Top and Higgs tagging studies with the ATLAS detector. The performance of 2 variable taggers, HEPTopTagger and shower deconstruction are compared in Monte Carlo simulations. To asses the modelling of the taggers’ performance, the tagging efficiencies are measured, with the full 2015+2016 dataset, in semi-leptonic top quark pair events and the background rejections are measured in dijet and photon+jet topologies. Recent developments in subjet reconstruction techniques for high transverse momentum Higgs->bb tagging are also presented.
Structure of potentials with N Higgs doublets
International Nuclear Information System (INIS)
Nishi, C. C.
2007-01-01
Extensions of the standard model with N Higgs doublets are simple extensions presenting a rich mathematical structure. An underlying Minkowski structure emerges from the study of both variable space and parameter space. The former can be completely parametrized in terms of two future lightlike Minkowski vectors with spatial parts forming an angle whose cosine is -(N-1) -1 . For the parameter space, the Minkowski parametrization enables one to impose sufficient conditions for bounded below potentials, characterize certain classes of local minima, and distinguish charge breaking vacua from neutral vacua. A particular class of neutral minima presents a degenerate mass spectrum for the physical charged Higgs bosons
Joint resummation for Higgs boson production
International Nuclear Information System (INIS)
Kulesza, Anna; Sterman, George; Vogelsang, Werner
2004-01-01
We study the application of the joint resummation formalism to Higgs boson production via gluon-gluon fusion at the CERN LHC, defining inverse transforms by analytic continuation. We work at next-to-leading logarithmic accuracy. We find that at low Q T the resummed Higgs Q T distributions are comparable in the joint and pure-Q T formalisms, with a relatively small influence from threshold enhancement in this range. We find a modest (about ten percent) decrease in the inclusive cross section, relative to pure threshold resummation
Asymptotically Free Natural Supersymmetric Twin Higgs Model
Badziak, Marcin; Harigaya, Keisuke
2018-05-01
Twin Higgs (TH) models explain the absence of new colored particles responsible for natural electroweak symmetry breaking (EWSB). All known ultraviolet completions of TH models require some nonperturbative dynamics below the Planck scale. We propose a supersymmetric model in which the TH mechanism is introduced by a new asymptotically free gauge interaction. The model features natural EWSB for squarks and gluino heavier than 2 TeV even if supersymmetry breaking is mediated around the Planck scale, and has interesting flavor phenomenology including the top quark decay into the Higgs boson and the up quark which may be discovered at the LHC.
BSM Higgs results from ATLAS and CMS
Directory of Open Access Journals (Sweden)
Flechl Martin
2013-11-01
Full Text Available Résumé. Searches for Higgs bosons in different extensions of the Standard Model (SM are presented. These include the Minimal Supersymmetric extension of the SM (MSSM, the next-to-MSSM (NMSSM, models with additional scalar singlets, doublets, or triplets, and generic searches for models with couplings modified with respect to the SM or for non-SM Higgs boson decay channels. Results are based on data collected by the ATLAS and CMS experiments in 2011 and 2012 at the LHC. No excess is found in any of the searches and thus the resulting exclusion limits are given.
Composite Higgs under LHC Experimental Scrutiny
Directory of Open Access Journals (Sweden)
Mühlleitner M.
2012-06-01
Full Text Available The LHC has been built to understand the dynamics at the origin of the breaking of the electroweak symmetry. Weakly coupled models with a fundamental Higgs boson have focused most of the attention of the experimental searches. We will discuss here how to reinterpret these searches in the context of strongly coupled models where the Higgs boson emerges as a composite particle. In particular, we use LHC data to constrain the compositeness scale. We also briefly review the prospects to observe other bosonic and fermionic resonances of the strong sector.
WIMP Dark Matter interpretation of Higgs results
Wang, Renjie; The ATLAS collaboration
2017-01-01
The results from searching for dark matter either directly from invisible decay of Higgs bosons or in association with a Higgs boson at the LHC are presented. No significant excess is found beyond the Standard Model prediction, and upper limits are set on the production cross section times branching fraction using data collected in proton-proton collisions at center-of-mass energies of 13 TeV by the ATLAS and CMS detectors. An interpreted upper limit is presented on the allowed dark matter-nucleon scattering cross section.
Can gravity do what Higgs does?
International Nuclear Information System (INIS)
Pawlowski, M.
1990-12-01
Conformally invariant model unifying gravity with the Standard Model is proposed. It is based on the observation that the conformal factor couples to matter fields analogously as the Higgs field does so for the proper choice of coupling parameters it can cancel divergences connected with longitudinal boson exchange. The criteria of stability, renormalizability and proper Einsteinian limit suggest that higher derivative terms are necessary in the gravitational sector. This introduces one new parameter but two old parameters of the Higgs potential are redundant due to unification. The Planck mass becomes a dynamical parameter characterizing gravitational background in accordance with Mach's philosophy. Cosmological constant appears in a natural way. (author). 18 refs
Higgs results and prospects at ATLAS
International Nuclear Information System (INIS)
Rosati, S.
2015-01-01
Highlights of a selection of the recent results of Run-1 measurements of the Higgs boson properties, with the ATLAS experiment at LHC, are presented. The results have been obtained with up to 25 fb −1 of proton-proton collisions at center of mass energy of 7 and 8TeV. Prospects in the field of Higgs properties measurements, with the data that will be collected at the future LHC runs, with up to 3000 fb −1 , are also discussed.
Maxwell-Higgs vortices with internal structure
Bazeia, D.; Marques, M. A.; Menezes, R.
2018-05-01
Vortices are considered in relativistic Maxwell-Higgs systems in interaction with a neutral scalar field. The gauge field interacts with the neutral field via the presence of generalized permeability, and the charged and neutral scalar fields interact in a way dictated by the presence of first order differential equations that solve the equations of motion. The neutral field may be seen as the source field of the vortex, and we study some possibilities, which modify the standard Maxwell-Higgs solution and include internal structure to the vortex.
Higgs mixing in the NMSSM and light higgsinos
International Nuclear Information System (INIS)
Jeong, Kwang Sik; Shoji, Yutaro; Yamaguchi, Masahiro
2014-12-01
We explore the effects of Higgs mixing in the general next-to-minimal supersymmetric Standard Model (NMSSM). Extended to include a gauge singlet, the Higgs sector can naturally explain the observed Higgs boson mass in TeV scale supersymmetry without invoking large stop mixing. This is particularly the case when the singlet scalar is light so that singlet-doublet mixing increases the mass of the SM-like Higgs boson. In such a case the Higgs mixing has interesting implications following from the fact that the higgsino mass parameter and the singlet coupling to Higgs bilinear crucially depend on the Higgs boson masses and mixing angles. For the mixing compatible with the current LHC data on the Higgs signal rates, the higgsinos are required to be relatively light, around or below a few hundred GeV, as long as the heavy doublet Higgs boson has a mass smaller than about 250√(tanβ) GeV and the singlet-like Higgs boson is consistent with the LEP constraint. In addition, the Higgs coupling to photons can receive a sizable contribution of either sign from the charged-higgsino loops combined with singlet-doublet mixing.
Beyond the Standard Model Higgs searches at the LHC
Meridiani, P
2015-01-01
The Run I at the LHC marks the birth of the "Higgs physics", a path which will be followed at its full extent in the future runs of the LHC. Indeed there are two complementary paths to be followed to new physics in the Higgs sector: precision measurements of the Higgs properties (couplings, mass, spin and parity), where new physics can manifest as deviation from the Standard Model, or direct search for processes not foreseen in the Standard Model (Higgs decays not foreseen in the Standard Model, additional scalars which would indicate an extended Higgs sector). The current status of these studies at the LHC is presented, focussing in particular on the direct searches for rare or invisible Higgs decays or for an extended Higgs sector. The results are based on the analysis of the proton-proton collisions at 7 and 8 TeV center-of-mass energy at the LHC by the ATLAS and CMS collaborations.
Probing hidden sector photons through the Higgs window
International Nuclear Information System (INIS)
Ahlers, M.
2008-07-01
We investigate the possibility that a (light) hidden sector extra photon receives its mass via spontaneous symmetry breaking of a hidden sector Higgs boson, the so-called hidden-Higgs. The hidden-photon can mix with the ordinary photon via a gauge kinetic mixing term. The hidden-Higgs can couple to the Standard Model Higgs via a renormalizable quartic term - sometimes called the Higgs Portal. We discuss the implications of this light hidden-Higgs in the context of laser polarization and light-shining-through-the-wall experiments as well as cosmological, astrophysical, and non-Newtonian force measurements. For hidden-photons receiving their mass from a hidden-Higgs we find in the small mass regime significantly stronger bounds than the bounds on massive hidden sector photons alone. (orig.)
Probing hidden sector photons through the Higgs window
International Nuclear Information System (INIS)
Ahlers, Markus; Jaeckel, Joerg; Redondo, Javier; Ringwald, Andreas
2008-01-01
We investigate the possibility that a (light) hidden sector extra photon receives its mass via spontaneous symmetry breaking of a hidden sector Higgs boson, the so-called hidden-Higgs. The hidden-photon can mix with the ordinary photon via a gauge kinetic mixing term. The hidden-Higgs can couple to the standard model Higgs via a renormalizable quartic term - sometimes called the Higgs portal. We discuss the implications of this light hidden-Higgs in the context of laser polarization and light-shining-through-the-wall experiments as well as cosmological, astrophysical, and non-Newtonian force measurements. For hidden-photons receiving their mass from a hidden-Higgs, we find in the small mass regime significantly stronger bounds than the bounds on massive hidden sector photons alone.
Doubling down on naturalness with a supersymmetric twin Higgs
International Nuclear Information System (INIS)
Craig, Nathaniel; Howe, Kiel
2014-01-01
We show that naturalness of the weak scale can be comfortably reconciled with both LHC null results and observed Higgs properties provided the double protection of supersymmetry and the twin Higgs mechanism. This double protection radically alters conventional signs of naturalness at the LHC while respecting gauge coupling unification and precision electroweak limits. We find the measured Higgs mass, couplings, and percent-level naturalness of the weak scale are compatible with stops at ∼3.5 TeV and higgsinos at ∼1 TeV. The primary signs of naturalness in this scenario include modifications of Higgs couplings, a modest invisible Higgs width, resonant Higgs pair production, and an invisibly-decaying heavy Higgs
Doubling down on naturalness with a supersymmetric twin Higgs
Craig, Nathaniel; Howe, Kiel
2014-03-01
We show that naturalness of the weak scale can be comfortably reconciled with both LHC null results and observed Higgs properties provided the double protection of supersymmetry and the twin Higgs mechanism. This double protection radically alters conventional signs of naturalness at the LHC while respecting gauge coupling unification and precision electroweak limits. We find the measured Higgs mass, couplings, and percent-level naturalness of the weak scale are compatible with stops at ~ 3.5 TeV and higgsinos at ~ 1 TeV. The primary signs of naturalness in this scenario include modifications of Higgs couplings, a modest invisible Higgs width, resonant Higgs pair production, and an invisibly-decaying heavy Higgs.
Higgs detectability in the extended supersymmetric standard model
International Nuclear Information System (INIS)
Kamoshita, Jun-ichi
1995-01-01
Higgs detectability at a future linear collider are discussed in the minimal supersymmetric standard model (MSSM) and a supersymmetric standard model with a gauge singlet Higgs field (NMSSM). First, in the MSSM at least one of the neutral scalar Higgs is shown to be detectable irrespective of parameters of the model in a future e + e - linear collider at √s = 300-500 GeV. Next the Higgs sector of the NMSSM is considered, since the lightest Higgs boson can be singlet dominated and therefore decouple from Z 0 boson it is important to consider the production of heavier Higgses. It is shown that also in this case at least one of the neutral scalar Higgs will be detectable in a future linear collider. We extend the analysis and show that the same is true even if three singlets are included. Thus the detectability of these Higgs bosons of these models is guaranteed. (author)
Higgs physics as a proble of new physics
International Nuclear Information System (INIS)
KANEMURA, S.
2014-01-01
The discovery of the Higgs boson at the LHC has opened the door to clarifying the mechanism of electroweak symmetry breaking and the origin of particle masses. The Higgs sector in the SM is the simplest possible one but is not based on a fundamental theoretical principle, so that there is also the possibility of non-minimal Higgs sectors. While the standard model is not in contradiction with current LHC data within the errors, many extended Higgs sectors can also reproduce these data. An extended Higgs sector often appears in new physics models beyond the standard model, so that this allows to determine new physics from the Higgs sector. In this talk, we discuss various aspects of extended Higgs sectors, in particular their phenomenological properties and testability at future experiments, as the International Linear Collider.
Probing baryogenesis through the Higgs boson self-coupling
Reichert, M.; Eichhorn, A.; Gies, H.; Pawlowski, J. M.; Plehn, T.; Scherer, M. M.
2018-04-01
The link between a modified Higgs self-coupling and the strong first-order phase transition necessary for baryogenesis is well explored for polynomial extensions of the Higgs potential. We broaden this argument beyond leading polynomial expansions of the Higgs potential to higher polynomial terms and to nonpolynomial Higgs potentials. For our quantitative analysis we resort to the functional renormalization group, which allows us to evolve the full Higgs potential to higher scales and finite temperature. In all cases we find that a strong first-order phase transition manifests itself in an enhancement of the Higgs self-coupling by at least 50%, implying that such modified Higgs potentials should be accessible at the LHC.
Phenomenology of a nonstandard Higgs boson in WLWL scattering
International Nuclear Information System (INIS)
Koulovassilopoulos, V.; Chivukula, R.S.
1994-01-01
In this paper we consider the phenomenology of a nonstandard Higgs boson in longitudinal gauge boson scattering. First, we present a composite Higgs model [based on an SU(4)/Sp(4) chiral-symmetry breaking pattern] in which there is a nonstandard Higgs boson. Then we explore, in a model-independent way, the phenomenology of such a nonstandard Higgs boson by calculating the leading one-loop logarithmic corrections to longitudinal gauge boson scattering. This calculation is done using the equivalence theorem and the Higgs boson is treated as a scalar-isoscalar resonance coupled to the Goldstone bosons of the SU(2) L xSu(2) R /SU(2) V chiral symmetry breaking. We show that the most important deviation from the one-Higgs-doublet standard model is parametrized by one unknown coefficient which is related to the Higgs-boson width. The implications for future hadron colliders are discussed
Higgs decays to dark matter: Beyond the minimal model
International Nuclear Information System (INIS)
Pospelov, Maxim; Ritz, Adam
2011-01-01
We examine the interplay between Higgs mediation of dark-matter annihilation and scattering on one hand and the invisible Higgs decay width on the other, in a generic class of models utilizing the Higgs portal. We find that, while the invisible width of the Higgs to dark matter is now constrained for a minimal singlet scalar dark matter particle by experiments such as XENON100, this conclusion is not robust within more generic examples of Higgs mediation. We present a survey of simple dark matter scenarios with m DM h /2 and Higgs portal mediation, where direct-detection signatures are suppressed, while the Higgs width is still dominated by decays to dark matter.
Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions
International Nuclear Information System (INIS)
Chien, Y.T.; Cirigliano, V.; Dekens, W.; Vries, J. de; Mereghetti, E.
2016-01-01
We investigate direct and indirect constraints on the complete set of anomalous CP-violating Higgs couplings to quarks and gluons originating from dimension-6 operators, by studying their signatures at the LHC and in electric dipole moments (EDMs). We show that existing uncertainties in hadronic and nuclear matrix elements have a significant impact on the interpretation of EDM experiments, and we quantify the improvements needed to fully exploit the power of EDM searches. Currently, the best bounds on the anomalous CP-violating Higgs interactions come from a combination of EDM measurements and the data from LHC Run 1. We argue that Higgs production cross section and branching ratios measurements at the LHC Run 2 will not improve the constraints significantly. On the other hand, the bounds on the couplings scale roughly linearly with EDM limits, so that future theoretical and experimental EDM developments can have a major impact in pinning down interactions of the Higgs.
The Higgs vacuum uplifted. Revisiting the electroweak phase transition with a second Higgs doublet
Energy Technology Data Exchange (ETDEWEB)
Dorsch, G.C. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Huber, S.J. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Mimasu, K. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Louvain Univ. Catholique, Louvain-la-Neuve (Belgium). Center for Cosmology, Particle Physics and Phenomenology; No, J.M. [King' s College, London (United Kingdom). Dept. of Physics; Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy
2017-05-25
The existence of a second Higgs doublet in Nature could lead to a cosmological first order electroweak phase transition and explain the origin of the matter-antimatter asymmetry in the Universe. We explore the parameter space of such a two-Higgs-doublet-model and show that a first order electroweak phase transition strongly correlates with a significant uplifting of the Higgs vacuum w.r.t. its Standard Model value. We then obtain the spectrum and properties of the new scalars H{sub 0}, A{sub 0} and H{sup ±} that signal such a phase transition, showing that the decay A{sub 0}→H{sub 0}Z at the LHC and a sizable deviation in the Higgs self-coupling λ{sub hhh} from its SM value are sensitive indicators of a strongly first order electroweak phase transition in the 2HDM.
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
International Nuclear Information System (INIS)
Gerhold, Philipp; Kallarackal, Jim; Humboldt-Universitaet, Berlin; Jansen, Karl
2011-11-01
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling. (orig.)
Upper and lower Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model
International Nuclear Information System (INIS)
Gerhold, Philipp Frederik Clemens
2009-01-01
Motivated by the advent of the Large Hadron Collider (LHC) the aim of the present work is the non-perturbative determination of the cutoff-dependent upper and lower mass bounds of the Standard Model Higgs boson based on first principle calculations, in particular not relying on additional information such as the triviality property of the Higgs- Yukawa sector or indirect arguments like vacuum stability considerations. For that purpose the lattice approach is employed to allow for a non-perturbative investigation of a chirally invariant lattice Higgs-Yukawa model, serving here as a reasonable simplification of the full Standard Model, containing only those fields and interactions which are most essential for the intended Higgs boson mass determination. These are the complex Higgs doublet as well as the top and bottom quark fields and their mutual interactions. To maintain the chiral character of the Standard Model Higgs-fermion coupling also on the lattice, the latter model is constructed on the basis of the Neuberger overlap operator, obeying then an exact global lattice chiral symmetry. Respecting the fermionic degrees of freedom in a fully dynamical manner by virtue of a PHMC algorithm appropriately adapted to the here intended lattice calculations, such mass bounds can indeed be established with the aforementioned approach. Supported by analytical calculations performed in the framework of the constraint effective potential, the lower bound is found to be approximately m low H (Λ)=80 GeV at a cutoff of Λ=1000 GeV. The emergence of a lower Higgs boson mass bound is thus a manifest property of the pure Higgs-Yukawa sector that evolves directly from the Higgs-fermion interaction for a given set of Yukawa coupling constants. Its quantitative size, however, turns out to be non-universal in the sense, that it depends on the specific form, for instance, of the Higgs boson self-interaction. The upper Higgs boson mass bound is then established in the strong coupling
Higgs, di-Higgs and tri-Higgs production via SUSY processes at the LHC with 14 TeV
van Beekveld, M.; Beenakker, W.; Caron, S.; Castelijn, R.; Lanfermann, M.; Struebig, A.
2015-01-01
We have systematically investigated the production of a Higgs boson with a mass of about 125 GeV in the decays of supersymmetric particles within the phenomenological MSSM (pMSSM). We find regions of parameter space that are consistent with all world data and that predict a sizeable rate of
Higgs bosons in the next-to-minimal supersymmetric standard model at the LHC
International Nuclear Information System (INIS)
Ellwanger, Ulrich
2011-01-01
We review possible properties of Higgs bosons in the NMSSM, which allow to discriminate this model from the MSSM: masses of mostly standard-model-like Higgs bosons at or above 140 GeV, or enhanced branching fractions into two photons, or Higgs-to-Higgs decays. In the case of a standard-model-like Higgs boson above 140 GeV, it is necessarily accompanied by a lighter state with a large gauge singlet component. Examples for such scenarios are presented. Available studies on Higgs-to-Higgs decays are discussed according to the various Higgs production modes, light Higgs masses and decay channels. (orig.)
International Nuclear Information System (INIS)
Tonini, Marco
2014-11-01
This thesis discusses the consistency of different Little Higgs models with the collected collider data as of the summer of 2013. Moreover, future prospects for possible discoveries and mass measurement methods of new physics signals at the foreseen LHC run II with increased center-of-mass energy are presented. Little Higgs models belong to a class of extensions of the Standard Higgs model, predicting a strong interaction regime at a compositeness scale Λ=4πf approximate global symmetry spontaneously broken at the scale f. A natural hierarchy between the compositeness and the electroweak scale is introduced by the Collective Symmetry Breaking mechanism: one-loop diagrams generating the Higgs mass term are forced to be at most logarithmically sensitive to Λ. A naturally light Higgs boson can thus be accommodated, consistently with a perturbative theory until a scale of order 10 TeV. We have probed the parameter space of three prominent examples of Little Higgs models, namely the Simplest Little Higgs model, the Littlest Higgs model, and the Littlest Higgs model with T-parity, against electroweak precision observables and the collected LHC data concerning both Higgs properties and direct searches for new particles, with √(s)=7,8 TeV and up to 25 fb -1 of integrated luminosity. Lower bounds on the scale f are set, within a certain degree of confidence level, which allow to draw conclusions on the ''naturalness'' of the different models. Optimisations of the existing direct searches setups, assuming a Little Higgs signal, as well as dedicated mass measurement methods designed for the foreseen LHC runs with √(s)=13,14 TeV are thoroughly discussed and proposed in this thesis. Special attention will be dedicated to final states including either a large or negligible fraction of missing transverse momentum. In particular, we will propose a dedicated collider search tailored for the discovery and mass measurement of a top partner, exploiting jet
Pseudo-Goldstone Higgs Doublets from Non-Vectorlike Grand Unified Higgs Sector
Hernández, A E Cárcamo
2016-01-01
We present a novel way of realizing the pseudo-Nambu-Goldstone boson mechanism for the doublet-triplet splitting in supersymmetric grand unified theories. The global symmetries of the Higgs sector are attributed to a non-vectorlike Higgs content, which is consistent with unbroken supersymmetry in a scenario with flat extra dimensions and branes. We also show how in such a model one can naturally obtain a realistic pattern for the Standard Model fermion masses and mixings.
Stiefel-Skyrem-Higgs models, their classical static solutions and Yang-Mills-Higgs monopoles
International Nuclear Information System (INIS)
Dobrev, V.K.
1981-07-01
A new series of models is introduced by adding Higgs fields to the earlier proposed euclidean four-dimensional Skyrme-like models with Yang-Mills composite fields constructed from Stiefel manifold-valued fields. The classical static versions of these models are discussed. The connection with the monopole solutions of the Yang-Mills-Higgs models in the Prasad-Sommerfield limit is pointed out and the BPS monopole is reobtained as an example. (author)
A comparison of the Higgs sectors of the CMSSM and NMSSM for a 126 GeV Higgs boson
International Nuclear Information System (INIS)
Beskidt, C.; Boer, W. de; Kazakov, D.I.
2013-01-01
The recent discovery of a Higgs-like boson at the LHC with a mass of 126 GeV has revived the interest in supersymmetric models, which predicted a Higgs boson mass below 130 GeV long before its discovery. We compare systematically the allowed parameter space in the constrained Minimal Supersymmetric Standard Model (CMSSM) and the Next-to-Minimal Supersymmetric Model (NMSSM) by minimizing the χ 2 function with respect to all known constraints from accelerators and cosmology using GUT scale parameters. For the CMSSM the Higgs boson mass at tree level is below the Z 0 boson mass and large radiative corrections are needed to obtain a Higgs boson mass of 126 GeV, which requires stop squark masses in the multi-TeV range. In contrast, for the NMSSM light stop quarks are allowed, since in the NMSSM at tree level the Higgs boson mass can be above the Z 0 boson mass from mixing with the additional singlet Higgs boson. Predictions for the scalar boson masses are given in both models with emphasis on the unique signatures of the NMSSM, where the heaviest scalar Higgs boson decays in the two lighter scalar Higgs bosons with a significant branching ratio, in which case one should observe double Higgs boson production at the LHC. Such a signal is strongly suppressed in the CMSSM. In addition, since the LSP is higgsino-like, Higgs boson decays into LSPs can be appreciable, thus leading to invisible Higgs decays
Predictions of the Higgs mass and the weak mixing angle in the 6D gauge-Higgs unification
International Nuclear Information System (INIS)
Hasegawa, Kouhei; Lim, Chong-Sa; Maru, Nobuhito
2016-01-01
In the gauge-Higgs unification with multiple extra spaces, the Higgs self-coupling is on the order of g 2 and the Higgs boson is predicted to be light, being consistent with the LHC results. When the gauge group is simple, the weak mixing angle is also predictable. We address a question on whether there exists a model of gauge-Higgs unification in six-dimensional space-time, which successfully predicts the mass ratios of the Higgs boson and weak gauge bosons. First, using a useful formula, we give a general argument on the condition for obtaining a realistic prediction of the weak mixing angle sin 2 θ W = 1/4, and find that triplet and sextet representations of the minimal SU(3) gauge group lead to the realistic prediction. Concerning the Higgs mass, we notice that, in the models with one Higgs doublet, the predicted Higgs mass is always the same: M H = 2M W . However, by extending our discussion to the models with two Higgs doublets, the situation changes: we obtain an interesting prediction M H ≤ 2M W at the leading order of the perturbation. Thus, it is possible to recover the observed Higgs mass, 125 GeV, for a suitable choice of the parameter. The situation is in clear contrast to the case of the minimal supersymmetric standard model, where M H ≤ M Z at the classical level and the predicted Higgs mass cannot recover the observed value. (author)
Exploring extended scalar sectors with di-Higgs signals: a Higgs EFT perspective
Corbett, Tyler; Joglekar, Aniket; Li, Hao-Lin; Yu, Jiang-Hao
2018-05-01
We consider extended scalar sectors of the Standard Model as ultraviolet complete motivations for studying the effective Higgs self-interaction operators of the Standard Model effective field theory. We investigate all motivated heavy scalar models which generate the dimension-six effective operator, | H|6, at tree level and proceed to identify the full set of tree-level dimension-six operators by integrating out the heavy scalars. Of seven models which generate | H|6 at tree level only two, quadruplets of hypercharge Y = 3 Y H and Y = Y H , generate only this operator. Next we perform global fits to constrain relevant Wilson coefficients from the LHC single Higgs measurements as well as the electroweak oblique parameters S and T. We find that the T parameter puts very strong constraints on the Wilson coefficient of the | H|6 operator in the triplet and quadruplet models, while the singlet and doublet models could still have Higgs self-couplings which deviate significantly from the standard model prediction. To determine the extent to which the | H|6 operator could be constrained, we study the di-Higgs signatures at the future 100 TeV collider and explore future sensitivity of this operator. Projected onto the Higgs potential parameters of the extended scalar sectors, with 30 ab-1 luminosity data we will be able to explore the Higgs potential parameters in all seven models.
Higgs production and decay in models of a warped extra dimension with a bulk Higgs
International Nuclear Information System (INIS)
Archer, Paul R.; Carena, Marcela; Carmona, Adrian; Neubert, Matthias
2015-01-01
Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS 5 space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusion and the H → γγ decay rate and show that they are finite (at one-loop order) as a consequence of gauge invariance. The extended scalar sector comprising the Kaluza-Klein excitations of the Standard Model scalars is constructed in detail. The largest effects are due to virtual KK fermions, whose contributions to the cross section and decay rate introduce a quadratic sensitivity to the maximum allowed value y * of the random complex entries of the 5D anarchic Yukawa matrices. We find an enhancement of the gluon-fusion cross section and a reduction of the H → γγ rate as well as of the tree-level Higgs couplings to fermions and electroweak gauge bosons. As a result, we perform a detailed study of the correlated signal strengths for different production mechanisms and decay channels as functions of y * , the mass scale of Kaluza-Klein resonances and the scaling dimension of the composite Higgs operator
NIVEL DE ACTIVIDAD FISICA, SEDENTARISMO Y VARIABLES ANTROPOMETRICAS EN FUNCIONARIOS PUBLICOS
Directory of Open Access Journals (Sweden)
Carolina Alemán R.
2006-12-01
Full Text Available El propósito de la investigación fue conocer la cantidad de actividad física que los funcionarios realizan durante la semana. Para ello participaron 84 personas con una edad promedio de 30.69 años, todos funcionarios del Programa de Atención Integral de Salud convenio UCR-CCSS; a quienes se les midió, el IMC, la circunferencia de la cintura y la cantidad de actividad física que realizaban por semana por medio del cuestionario de actividades físicas de Paffenbarger. Mediante análisis de varianza de una vía se determinaron diferencias significativas entre la circunferencia de la cintura de las mujeres y los hombres. No se encontró diferencia significativa en cuanto al nivel de sedentarismo entre hombres y mujeres. En cuanto al IMC, un 23% del total de la muestra presentó sobrepeso y un 14% obesidad. Estos datos indican porcentajes muy altos en factores de riesgo para la salud física de estos funcionarios, a pesar de ser adultos jóvenes, lo que lleva a la conclusión de que es imprescindible la intervención con programas que modifiquen estos factores de riesgo, como la práctica regular de actividad física, por medio de planes de acción diseñados de acuerdo a las posibilidades económicas, a las facilidades de acceso a lugares apropiados para la práctica física, o bien la educación de los funcionarios por parte de profesionales en el campo, para que puedan involucrar dentro de sus quehaceres diarios un estilo de vida más activo.
The Higgs boson resonance from a chiral Higgs-Yukawa model on the lattice
Energy Technology Data Exchange (ETDEWEB)
Kallarackal, Jim
2011-04-28
Despite the fact that the standard model of particle physics has been confirmed in many high energy experiments, the existence of the Higgs boson is not assured. The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for fermions and the weak gauge bosons. The goal of this work is to set limits on the mass and the decay width of the Higgs boson. The basis to compute the physical quantities is the path integral which is here evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. A polynomial hybrid Monte Carlo algorithm is used to incorporate dynamical fermions. The chiral symmetry of the electroweak model is incorporated by using the Neuberger overlap operator. Here, the standard model is considered in the limit of a Higgs-Yukawa sector which does not contain the weak gauge bosons and only a degenerate doublet of top- and bottom quarks are incorporated. Results from lattice perturbation theory up to one loop of the Higgs boson propagator are compared with those obtained from Monte Carlo simulations at three different values of the Yukawa coupling. At all values of the investigated couplings, the perturbative results agree very well with the Monte Carlo data. A main focus of this work is the investigation of the resonance parameters of the Higgs boson. The resonance width and the resonance mass are investigated at weak and at large quartic couplings. The parameters of the model are chosen such that the Higgs boson can decay into any even number of Goldstone bosons. Thus, the Higgs boson does not appear as an asymptotic stable state but as a resonance. In all considered cases the Higgs boson resonance width lies below 10% of the resonance mass. The obtained resonance mass is compared with the mass obtained from the Higgs boson propagator. The results agree perfectly at all values of the quartic coupling considered. Finally, the effect of a heavy fourth generation of fermions on the
The Higgs boson resonance from a chiral Higgs-Yukawa model on the lattice
International Nuclear Information System (INIS)
Kallarackal, Jim
2011-01-01
Despite the fact that the standard model of particle physics has been confirmed in many high energy experiments, the existence of the Higgs boson is not assured. The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for fermions and the weak gauge bosons. The goal of this work is to set limits on the mass and the decay width of the Higgs boson. The basis to compute the physical quantities is the path integral which is here evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. A polynomial hybrid Monte Carlo algorithm is used to incorporate dynamical fermions. The chiral symmetry of the electroweak model is incorporated by using the Neuberger overlap operator. Here, the standard model is considered in the limit of a Higgs-Yukawa sector which does not contain the weak gauge bosons and only a degenerate doublet of top- and bottom quarks are incorporated. Results from lattice perturbation theory up to one loop of the Higgs boson propagator are compared with those obtained from Monte Carlo simulations at three different values of the Yukawa coupling. At all values of the investigated couplings, the perturbative results agree very well with the Monte Carlo data. A main focus of this work is the investigation of the resonance parameters of the Higgs boson. The resonance width and the resonance mass are investigated at weak and at large quartic couplings. The parameters of the model are chosen such that the Higgs boson can decay into any even number of Goldstone bosons. Thus, the Higgs boson does not appear as an asymptotic stable state but as a resonance. In all considered cases the Higgs boson resonance width lies below 10% of the resonance mass. The obtained resonance mass is compared with the mass obtained from the Higgs boson propagator. The results agree perfectly at all values of the quartic coupling considered. Finally, the effect of a heavy fourth generation of fermions on the
Higgs mass from neutrino-messenger mixing
International Nuclear Information System (INIS)
Byakti, Pritibhajan; Khosa, Charanjit K.; Mummidi, V.S.; Vempati, Sudhir K.
2017-01-01
The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A t , relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.
Search for the Higgs boson theoretical perspectives
Ridolfi, G
2001-01-01
We present a short review of experimental and theoretical constraints on the mass of the Standard Model Higgs boson. We briefly illustrate the unsatisfactory aspects of the standard theory, and we present some general considerations about possible non-standard scenarios.
Multifield dynamics in Higgs-otic inflation
Energy Technology Data Exchange (ETDEWEB)
Bielleman, S.; Ibáñez, L.E.; Pedro, F.G.; Valenzuela, I. [Departamento de Física Teórica UAM and Instituto de Física Teórica UAM/CSIC,Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain)
2016-01-20
In Higgs-otic inflation a complex neutral scalar combination of the h{sup 0} and H{sup 0} MSSM Higgs fields plays the role of inflaton in a chaotic fashion. The potential is protected from large trans-Planckian corrections at large inflaton if the system is embedded in string theory so that the Higgs fields parametrize a D-brane position. The inflaton potential is then given by a DBI+CS D-brane action yielding an approximate linear behaviour at large field. The inflaton scalar potential is a 2-field model with specific non-canonical kinetic terms. Previous computations of the cosmological parameters (i.e. scalar and tensor perturbations) did not take into account the full 2-field character of the model, ignoring in particular the presence of isocurvature perturbations and their coupling to the adiabatic modes. It is well known that for generic 2-field potentials such effects may significantly alter the observational signatures of a given model. We perform a full analysis of adiabatic and isocurvature perturbations in the Higgs-otic 2-field model. We show that the predictivity of the model is increased compared to the adiabatic approximation. Isocurvature perturbations moderately feed back into adiabatic fluctuations. However, the isocurvature component is exponentially damped by the end of inflation. The tensor to scalar ratio varies in a region r=0.08–0.12, consistent with combined Planck/BICEP results.
Standard Model, Higgs Boson and What Next?
Indian Academy of Sciences (India)
IAS Admin
theory, Higgs boson discovery, quantum gravity ... end of the 20th century, in the theory of fundamental forces based on ... the dominant force for the Universe at large, because .... trast to electric charge which is just a number (positive, negative ...
Higgs mass from neutrino-messenger mixing
Energy Technology Data Exchange (ETDEWEB)
Byakti, Pritibhajan [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Department of Theoretical Physics, Indian Association for the Cultivation of Science,2A & 2B Raja S.C. Mullick Road, Kolkata 700 032 (India); Khosa, Charanjit K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Mummidi, V.S. [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); Vempati, Sudhir K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India)
2017-03-06
The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A{sub t}, relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.
Beyond MSSM Higgs Bosons at the LHC
CERN. Geneva
2011-01-01
We consider the Higgs sector in extensions of the Minimal Supersymmetric Standard Model by higher-dimension operators in the context of Higgs searches at the LHC 7 TeV run. Such an effective field theory (EFT) approach, also referred to as BMSSM, allows for a model-independent description that may correspond to the combined effects of additional supersymmetric sectors, such as heavy singlets, triplets or gauge bosons, in which the supersymmetry breaking mass splittings can be treated as a perturbation. We consider the current LHC dataset, to set exclusion limits on a large class of BMSSM models. We also present projections for integrated luminosities of 5 and 15 fb−1, assuming that the ATLAS and CMS collaborations will combine their results in each channel. Our study shows that the majority of the parameter space will be probed at the 2σ level with 15 fb−1 of data. A non-observation of a Higgs boson with about 10 fb−1 of data will point towards a Higgs SUSY spectrum with intermediate tan β ( ≈ a few...
Dilaton vs Higgs: Nearly Conformal Physics
Kozlov, G. A.
2016-04-01
We consider the model in which the conformal symmetry can be broken spontaneously, and a light scalar dilaton could emerge in the low-energy spectrum. The contribution of the dark photon production relevant to two photons decays of a Higgs boson/dilaton is discussed.
Swimming against the tide: explaining the Higgs
Emma Sanders
2012-01-01
"Never before in the field of science journalism have so few journalists understood what so many physicists were telling them!" tweeted the UK Channel 4’s Tom Clarke from last December’s Higgs seminar. As a consequence, most coverage focused on debates over the use of the label “god particle” and the level of excitement of the physicists (high), whilst glossing over what this excitement was actually all about. So what is the Higgs? Something fundamental. Something to do with mass. If your interest in physics is more than simply passing, you may find that rooms full of chattering politicians or the use of different footwear when walking through snow just don’t do the job in convincing you why the Higgs is so important. And if images of fish make you feel like a fish out of water - or at least one swimming against a strong current - then perhaps you would appreciate a different approach. The need for the Higgs Whilst gauge th...
Fitting Higgs data with nonlinear effective theory.
Buchalla, G; Catà, O; Celis, A; Krause, C
2016-01-01
In a recent paper we showed that the electroweak chiral Lagrangian at leading order is equivalent to the conventional [Formula: see text] formalism used by ATLAS and CMS to test Higgs anomalous couplings. Here we apply this fact to fit the latest Higgs data. The new aspect of our analysis is a systematic interpretation of the fit parameters within an EFT. Concentrating on the processes of Higgs production and decay that have been measured so far, six parameters turn out to be relevant: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. A global Bayesian fit is then performed with the result [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. Additionally, we show how this leading-order parametrization can be generalized to next-to-leading order, thus improving the [Formula: see text] formalism systematically. The differences with a linear EFT analysis including operators of dimension six are also discussed. One of the main conclusions of our analysis is that since the conventional [Formula: see text] formalism can be properly justified within a QFT framework, it should continue to play a central role in analyzing and interpreting Higgs data.
Prospects for Higgs searches at the LHC
International Nuclear Information System (INIS)
Dissertori, G.
2006-01-01
In this talk I will summarize the current simulation studies by the LHC experiments regarding the searches for Higgs bosons, both in the context of the Standard Model as well as its supersymmetric extension. Some emphasis will be given to the early discovery reach, as well as to recent studies regarding background estimations and systematic uncertainties. (author)
Rhenium-186 direct labelling HIgG
International Nuclear Information System (INIS)
Lungu, V.; Mihailescu, G.; Dumitrescu, G.
2001-01-01
The aim of this study is to develop and improve existing radiolabelling techniques of peptides and monoclonal antibodies with 186 Re for achievement of potential agents for cancer targeted radiotherapy. There were selected methods and techniques for the direct labelling of intact HIgG by studding chemical and radiochemical processes of -S-S- bridges prereduction, reduction of 186 ReO 4 - and coupling reaction of rhenium with HIgG. The -S-S- bridges prereduction of HIgG to sulfhydryls was effected using different reducing agents: ascorbic acid, 2,3 dimercaptopropanol, cysteine, active hydrogen. The prereduction reactions are controlled by masic ratios of HIgG/reduction agent, pH, temperature and time of incubation. A pH=4.5 and a 24 hours incubation time are in the advantage of the prereduction yield. The labelling with 186 Re of prereduced HIgG with ascorbic acid or active hydrogen and 37 deg. C incubation in 22 hours releases 92% radiochemical purity. (author)
Accelerating research into the Higgs boson particle
Nikolaidou, Rosy
"The only Standard Model particle yet to be observed, the search for the Higgs Boson - the so-called 'God Particle' - demands advanced facilities and physics expertise. At the Cern laboratory in Switzerland, the ARTEMIS project is well-placed to pursue research in this area" (2 pages)
The ATLAS Higgs machine learning challenge
Davey, W; The ATLAS collaboration; Rousseau, D; Cowan, G; Kegl, B; Germain-Renaud, C; Guyon, I
2014-01-01
High Energy Physics has been using Machine Learning techniques (commonly known as Multivariate Analysis) since the 90's with Artificial Neural Net for example, more recently with Boosted Decision Trees, Random Forest etc... Meanwhile, Machine Learning has become a full blown field of computer science. With the emergence of Big Data, Data Scientists are developing new Machine Learning algorithms to extract sense from large heterogeneous data. HEP has exciting and difficult problems like the extraction of the Higgs boson signal, data scientists have advanced algorithms: the goal of the HiggsML project is to bring the two together by a “challenge”: participants from all over the world and any scientific background can compete online ( https://www.kaggle.com/c/higgs-boson ) to obtain the best Higgs to tau tau signal significance on a set of ATLAS full simulated Monte Carlo signal and background. Winners with the best scores will receive money prizes ; authors of the best method (most usable) will be invited t...
Higgs instability and de Sitter radiation
Directory of Open Access Journals (Sweden)
Gaurav Goswami
2015-12-01
Full Text Available If the Standard Model (SM of elementary particle physics is assumed to hold good to arbitrarily high energies, then, for the best fit values of the parameters, the scalar potential of the Standard Model Higgs field turns negative at a high scale μinst. If the physics beyond the SM is such that it does not modify this feature of the Higgs potential and if the Hubble parameter during inflation (Hinf is such that Hinf≫μinst, then, quantum fluctuations of the SM Higgs during inflation make it extremely unlikely that after inflation it will be found in the metastable vacuum at the weak scale. In this work, we assume that (i during inflation, the SM Higgs is in Bunch–Davies vacuum state, and, (ii the question about the stability of the effective potential must be answered in the frame of the freely falling observer (just like in Minkowski spacetime, and then use the well-known fact that the freely falling observer finds Bunch–Davies vacuum to be in thermal state to show that the probability to end up in the electroweak vacuum after inflation is reasonably high.
Abelian Higgs mechanism in the Schroedinger picture
International Nuclear Information System (INIS)
Kim, S.K.; Namgung, W.; Soh, K.S.; Yee, J.H.
1990-01-01
We have studied symmetry-breaking phenomena in scalar electrodynamics by evaluating the effective potential at one-loop order in the Schroedinger picture. Contributions to the effective potential by the Higgs particle and the transverse and longitudinal components of a photon are compared with other previous works, and they are found to be consistent