Motivated by the recent CDF measurement of the W-boson mass, we study string-based particle physics models which can accommodate this deviation from the Standard Model. We consider an F-theory GUT in ...which the visible sector is realized on intersecting 7-branes, and extra sector states arise from a probe D3-brane near an E-type Yukawa point. The D3-brane worldvolume naturally realizes a strongly coupled sector which mixes with the Higgs. In the limit where some extra sector states get their mass solely from Higgs vevs, this leads to a contribution to the ρ parameter which is too large, but as the D3-brane is separated from the 7-brane stack, this effect is suppressed, leading to O(1) - O(10) TeV scale extra sector states and a correction to ρ which would be in accord with the CDF result. We also estimate the contribution to the oblique electroweak parameter S, and find that it is compatible with existing constraints. This also leads to additional signatures, including diphoton resonances (as well as other diboson final states) in the O(1) - O(10) TeV range.
A
bstract
We study (1, 0) and (2, 0) 6D superconformal field theories (SCFTs) that can be constructed in F-theory. Quite surprisingly, all of them involve an orbifold singularity ℂ
2
/Γ with Γ a ...discrete subgroup of U(2). When Γ is a subgroup of
SU
(2), all discrete subgroups are allowed, and this leads to the familiar ADE classification of (2, 0) SCFTs. For more general U(2) subgroups, the allowed possibilities for Γ are not arbitrary and are given by certain generalizations of the A- and D-series. These theories should be viewed as the minimal 6D SCFTs. We obtain all other SCFTs by bringing in a number of E-string theories and/or decorating curves in the base by non-minimal gauge algebras. In this way we obtain a vast number of new 6D SCFTs, and we conjecture that our construction provides a full list.
6D fractional quantum Hall effect Heckman, Jonathan J.; Tizzano, Luigi
The journal of high energy physics,
05/2018, Volume:
2018, Issue:
5
Journal Article
Peer reviewed
Open access
A
bstract
We present a 6D generalization of the fractional quantum Hall effect involving membranes coupled to a three-form potential in the presence of a large background four-form flux. The low ...energy physics is governed by a bulk 7D topological field theory of abelian three-form potentials with a single derivative Chern-Simons-like action coupled to a 6D anti-chiral theory of Euclidean effective strings. We derive the fractional conductivity, and explain how continued fractions which figure prominently in the classification of 6D superconformal field theories correspond to a hierarchy of excited states. Using methods from conformal field theory we also compute the analog of the Laughlin wavefunction. Compactification of the 7D theory provides a uniform perspective on various lower-dimensional gapped systems coupled to boundary degrees of freedom. We also show that a supersymmetric version of the 7D theory embeds in M-theory, and can be decoupled from gravity. Encouraged by this, we present a conjecture in which IIB string theory is an edge mode of a 10 + 2-dimensional bulk topological theory, thus placing all twelve dimensions of F-theory on a physical footing.
6D SCFTs and phases of 5D theories Del Zotto, Michele; Heckman, Jonathan J.; Morrison, David R.
The journal of high energy physics,
09/2017, Volume:
2017, Issue:
9
Journal Article
Peer reviewed
Open access
A
bstract
Starting from 6D superconformal field theories (SCFTs) realized via F-theory, we show how reduction on a circle leads to a uniform perspective on the phase structure of the resulting 5D ...theories, and their possible conformal fixed points. Using the correspon-dence between F-theory reduced on a circle and M-theory on the corresponding elliptically fibered Calabi-Yau threefold, we show that each 6D SCFT with minimal supersymmetry directly reduces to a collection of between one and four 5D SCFTs. Additionally, we find that in most cases, reduction of the tensor branch of a 6D SCFT yields a 5D generalization of a quiver gauge theory. These two reductions of the theory often correspond to different phases in the 5D theory which are in general connected by a sequence of flop transitions in the extended Kähler cone of the Calabi-Yau threefold. We also elaborate on the structure of the resulting conformal fixed points, and emergent flavor symmetries, as realized by M-theory on a canonical singularity.
We consider a class of 6D superconformal field theories (SCFTs) which have a large N limit and a semi-classical gravity dual description. Using the quiver-like structure of 6D SCFTs we study a ...subsector of operators protected from large operator mixing. These operators are characterized by degrees of freedom in a one-dimensional spin chain, and the associated states are generically highly entangled. This provides a concrete realization of qubit-like states in a strongly coupled quantum field theory. Renormalization group flows triggered by deformations of 6D UV fixed points translate to specific deformations of these one-dimensional spin chains. We also present a conjectural spin chain Hamiltonian which tracks the evolution of these states as a function of renormalization group flow, and study qubit manipulation in this setting. Similar considerations hold for theories without AdS duals, such as 6D little string theories and 4D SCFTs obtained from compactification of the partial tensor branch theory on a T2.
M5-branes probing an ADE singularity lead to 6D SCFTs with (1,0) supersymmetry. On the tensor branch, the M5-branes specify domain walls of a 7D Super Yang–Mills theory with gauge group G of ...ADE-type, thus providing conformal matter for a broad class of generalized quiver theories. Additionally, these theories have G×G flavor symmetry, and a corresponding Higgs branch. In this Note we use the F-theory realization of these theories to calculate the scaling dimension of the operator parameterizing seven-brane recombination, i.e. motion of the stack of M5-branes off of the orbifold singularity. In all cases with an interacting fixed point, we find that this operator has scaling dimension at least six, and defines a marginal irrelevant deformation.
6D RG flows and nilpotent hierarchies Heckman, Jonathan J.; Rudelius, Tom; Tomasiello, Alessandro
The journal of high energy physics,
07/2016, Volume:
2016, Issue:
7
Journal Article
Peer reviewed
Open access
A
bstract
With the eventual aim of classifying renormalization group flows between 6D superconformal field theories (SCFTs), we study flows generated by the vevs of “conformal matter,” a ...generalization of conventional hypermultiplets which naturally appear in the F-theory classification of 6D SCFTs. We consider flows in which the parent UV theory is (on its partial tensor branch) a linear chain of gauge groups connected by conformal matter, with one flavor group
G
at each end of the chain, and in which the symmetry breaking of the conformal matter at each end is parameterized by the orbit of a nilpotent element, i.e. T-brane data, of one of these flavor symmetries. Such nilpotent orbits admit a partial ordering, which is reflected in a hierarchy of IR fixed points. For each such nilpotent orbit, we determine the corresponding tensor branch for the resulting SCFT. An important feature of this algebraic approach is that it also allows us to systematically compute the unbroken flavor symmetries inherited from the parent UV theory.
6d Conformal matter Del Zotto, Michele; Heckman, Jonathan J.; Tomasiello, Alessandro ...
The journal of high energy physics,
02/2015, Volume:
2015, Issue:
2
Journal Article
Peer reviewed
Open access
A
bstract
A single M5-brane probing
G
, an ADE-type singularity, leads to a system which has
G
×
G
global symmetry and can be viewed as “bifundamental” (
G, G
) matter. For the
A
N
series, this leads ...to the usual notion of bifundamental matter. For the other cases it corresponds to a strongly interacting (1
,
0) superconformal system in six dimensions. Similarly, an ADE singularity intersecting the Hořava-Witten wall leads to a superconformal matter system with
E
8
×
G
global symmetry. Using the F-theory realization of these theories, we elucidate the Coulomb/tensor branch of (
G, G
′) conformal matter. This leads to the notion of fractionalization of an M5-brane on an ADE singularity as well as fractionalization of the intersection point of the ADE singularity with the Hořava-Witten wall. Partial Higgsing of these theories leads to new 6d SCFTs in the infrared, which we also characterize. This generalizes the class of (1
,
0) theories which can be perturbatively realized by suspended branes in IIA string theory. By reducing on a circle, we arrive at novel duals for 5d affine quiver theories. Introducing many M5-branes leads to large
N
gravity duals.
Fission, fusion, and 6D RG flows Heckman, Jonathan J.; Rudelius, Tom; Tomasiello, Alessandro
The journal of high energy physics,
02/2019, Volume:
2019, Issue:
2
Journal Article
Peer reviewed
Open access
A
bstract
We show that all known 6D SCFTs can be obtained iteratively from an underlying set of UV progenitor theories through the processes of “fission” and “fusion”. Fission consists of a tensor ...branch deformation followed by a special class of Higgs branch deformations characterized by discrete and continuous homomorphisms into flavor symmetry algebras. Almost all 6D SCFTs can be realized as fission products. The remainder can be constructed via one step of fusion involving these fission products, whereby a single common flavor symmetry of decoupled 6D SCFTs is gauged and paired with a new tensor multiplet at the origin of moduli space, producing an RG flow “in reverse” to the UV. This leads to a streamlined labeling scheme for all known 6D SCFTs in terms of a few pieces of group theoretic data. The partial ordering of continuous homomorphisms
s
u
2
→
g
flav
for
g
flav
a flavor symmetry also points the way to a classification of 6D RG flows.
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