Edited by Hye-Sung Lee
This is an on-line "The Z' Hunter's Guide" to provide a basic
but up-to-date review to people who are interested in Z' physics.
At this point, it is just a collection of the links to some Z'
papers I personally think useful.
I plan to keep updating and refining it until it becomes a
comprehensive review of the Z' physics.
Please let me know your ideas and suggestions to improve this site.
;)
We define our Z' as the new force carrier of an additional U(1)
gauge symmetry unless otherwise indicated.
Useful Links:
- Tevatron
- LHC
- ILC
- CLIC
- VLHC
- U(1)' (additional U(1) symmetry)
- Part of non-Abelian gauge symmetry such as SU(2)_R (the
third component)
- Kaluza-Klein excitations in extra dimension.
- String resonance
- GUT
- Extra Dimension
- Superstring
-
Classification of Flat Directions in Perturbative Heterotic Superstring Vacua with Anomalous U(1) [G. Cleaver, M. Cvetic, J.R. Espinosa, L.L. Everett, P. Langacker (1997)]
-
Physics Implications of Flat Directions in Free Fermionic Superstring Models I: Mass Spectrum and Couplings [G. Cleaver, M. Cvetic, J.R. Espinosa, L.L. Everett, P. Langacker, J. Wang (1998)]
-
Physics Implications of Flat Directions in Free Fermionic Superstring Models II: Renormalization Group Analysis [G. Cleaver, M. Cvetic, J.R. Espinosa, L.L. Everett, P. Langacker, J. Wang (1998)]
-
New Gauge Bosons from String Models [M. Cvetic, P. Langacker (1996)]
-
Toward Realistic Intersecting D-Brane Models [R. Blumenhagen, M. Cvetic, P. Langacker, G. Shiu (2005)]
- Strong Dynamics
- Little Higgs
-
Electroweak symmetry breaking from dimensional deconstruction [N. Arkani-Hamed, A.G. Cohen, H. Georgi (2001)]
-
The Minimal Moose for a Little Higgs [N. Arkani-Hamed, A.G. Cohen, E. Katz, A.E. Nelson, T. Gregoire, J.G. Wacker (2002)]
-
Phenomenology of the Little Higgs Model [T. Han, H.E. Logan, B. McElrath, L.T. Wang (2003)]
- Stueckelberg mechanism
-
How Stueckelberg Extends the Standard Model and the MSSM [B. Kors, P. Nath (2004)]
-
A Supersymmetric Stueckelberg U(1) Extension of the MSSM [B. Kors, P. Nath (2004)]
-
Aspects of the Stueckelberg Extension [B. Kors, P. Nath (2005)]
-
The Stueckelberg Z Prime at the LHC: Discovery Potential, Signature Spaces and Model Discrimination [D. Feldman, Z. Liu, P. Nath (2006)]
-
Extra-weakly Interacting Dark Matter [D. Feldman, B. Kors, P. Nath (2006)]
-
Hidden fermion as milli-charged dark matter in Stueckelberg Z' model [K. Cheung, T.C. Yuan (2007)]
-
The Stueckelberg Extension and Milli Weak and Milli Charge Dark Matter [D. Feldman, Z. Liu, P. Nath (2007)]
- One or more additional scalar fields are required to break the U(1)' symmetry.
- U(1)' symmetry breaking can be related to the EWSB and
SUSY breaking especially when they are broken at TeV-scale.
- Especially, the TeV-scale U(1)' model can explain the
mu-problem.
-
The mu-term in the MSSM (Minimal Supersymmetric Standard
Model) is the only dimensionful parameter in the
supersymmetry conserving sector.
To have the electroweak symmetry breaking at the
right-order, mu should be of the same order of supersymmetry
breaking (TeV-scale) but the MSSM does not explain its
origin.
The mu in a U(1)' model is the vacuum expectation value of
the singlet Higgs that is broken at TeV scale.
Since it is the continuous gauge symmetry, it does not have
the domain wall problem which is invoked in the
NMSSM (Next-to-Minimal Supersymmetric Standard Model) that
has the singlet with the discrete symmetry.
-
There are more explicit models for the TeV-scale supersymmetric U(1)' that solve the mu-problems.
- Bottom-Up rationale for the TeV-scale Z'
- Top-Down rationale for the TeV-scale Z'
- SUSY breaking and U(1)'
-
Another solution of the mu-problem: The mu-term is absent by
a symmetry but an effective mu-term is
generated by non-renormalizable operators
-
A number of string models possess non-renormalizable terms
in the Kahler potential, which are proportional to H1 H2,
and may thus provide a resolution to the mu-problem.
-
In Erice 1992 Proceedings From Superstrings to Super-
gravity (World Scientific 1994, M. Duff et al., eds.), p
234. [V. Kaplunovsky, J. Louis]
-
Effective Mu-Term in Superstring Theory [I. Antoniadis, E. Gava, K.S. Narain, T.R. Taylor (1994)]
-
Moduli spaces and target space duality symmetries in (0,2) Z_N orbifold theories with continuous Wilson lines [G. Lopes Cardoso, D. Luest, T. Mohaupt (1994)]
-
Another solution of the mu-problem: With an anomalous U(1)'
symmetry
-
This anomalous U(1)' symmetry was originally introduced to explain the
Yukawa textures.
-
The anomaly may be cancelled by the Green-Schwarz mechanism.
-
Common solution of the mu-problem and strong CP-problem.
- The U(1)' charge assignments should be careful chosen to make
the model anomaly-free. (GUT-originated U(1)'s are
automatically anomaly-free.)
- It is not easy to embed a TeV-scale U(1)' in a GUT model.
The E6 GUT, for example, cannot provide the TeV-scale Z'
since the E6 exotics of the TeV-scale would induce a fast
proton decay.
-
String-derived models also have exotics (such as color
triplets) that could mediate a too fast proton decay.
- If the right-handed neutrinos are charged by U(1)' of
TeV-scale, the neutrinos would be Dirac neutrinos unless in
the limit the right-handed neutrinos charges are zero.
It loses the advantage of the simplicity of the seesaw
mechanism available for the Majorana neutrinos.
- Electroweak precision data is already well explained by the
Standard Model.
- U(1)' may protect the proton decay
- The U(1)' anomaly cancellation may require the exotic fields. Their coupling and masses can get the cosmological constraints.
- U(1)' anomaly cancellation may require the exotic quarks and
- Anomaly-free U(1) family symmetry
- Family-dependent U(1)' charge and the non-holomorphic
soft terms can provide anomaly-free U(1)' model.
- Massless Z' is possible through a high dimensional operator.
- Milicharged particles from the kinetic mixing of photon and another U(1)_ex gauge boson may explain the PVLAS experiment.
- Z' Model building is posible without an exotic particle that couples to SM
gauge bosons
- If new particles are gauged by a U(1)', their electromagnetic charges may be shifted by a calculable amount.
- A new long-range force coupling is constrained to be
small.
- A peculiar extra U(1) with anomaly cancellation in an economical way
- Proton decay and chirality issue
- R-parity may not be necessary.
- Generic D-brane string models predict U(1)'.
- U(1)' in Non-Commutative physics
-
U(1)_x model that solves the tachyonic slepton problem of AMSB.
-
U(1) gauge field localed on brane can have a milicharge.
-
The generalization of the B-L symmetry with generation-dependent lepton
charges leads to neutrino masses induced by operators of high
dimensionality.
-
Shadow Higgs
- 3-3-1 model
- U(1)_B
- The most recent Fermilab result on dielectron search of Z'
(from CDF exotic group)
The most significant region of
excess of data over background occurs for an
e+e- invariant mass window of 240
GeV/c2 with 3.8 standard deviations above the SM prediction.
- Direct Collider search of the Resonance
The direct discovery channel of the Z' would be the
observation of the resonance peak of the Z' in difermion
channels.
Especially the dilepton channel provides very clean
signals without much background.
The LHC reach of Z' resonance is expected to be 2
TeV at day 1!
-
CDF RunIIA results for Z' mass limit by dilepton (electron+muon) channels (talk [M. Karagoz Unel (2005)] at SUSY 2005)
-
Searches for New Physics at the Tevatron (slides) [D. Stuart (2004)]
-
Searches for New Physics in High Mass Dimuon Channel in CDF Run II Data (plots) [M.K. Unel, M. Schmitt, K. Maeshima, K. Ikado, T. Nelson (2004)]
-
Discovery and Measurement of Sleptons, Binos, and Winos with a Z' [M. Baumgart, T. Hartman, C. Kilic, L.T. Wang (2006)]
-
New Physics at TeV scale and Precision Electroweak (slides) [S. Godfrey (2005)]
-
Search for Z' with ATLAS (multiple slides)
-
Search
for New Gauge Bosons (multiple slides)
-
Z-prime Gauge Bosons at the Tevatron [M. Carena, A. Daleo, B.A. Dobrescu, T.M.P. Tait (2004)]
-
Prospects of a Search for a New Massless Neutral Gauge Boson at the ILC [E. Boos, V. Bunichev, H.J. Schreiber (2007)]
-
How to study weakly coupled neutral vector bosons [A. Freitas (2004)]
-
Z' Discovery Limits For Supersymmetric E_6 Models [J. Kang, P. Langacker (2004)]
: Z' discovery by jets may be improved by the prescale.
-
E_6 multiplets and unification in extra dimensions [B. Brahmachari (2002)]
: E6 exotics may exist at m_t scale.
-
Physics with Jets at the LHC [J.W. Rohlf (2005)]
-
A search for Z' bosons using dielectron mass & angular distribution at CDF (talk) [G. Veramendi (2005)]
: PHENO2005 talk from CDF collaboaration on Z' search
-
Some effects of a Z' vector boson (talk) [J. Boersma (2005)]
: Z'_SM and Z'-W-W coupling
-
HEAVY Z BOSON DECAYS TO W, Z AND HIGGS BOSONS IN E(6) SUPERSTRING MODELS [V.D. Barger, K. Whisnant (1987)]
-
Heavy-Z-boson decays to two bosons in E6 superstring models [V.D. Barger, K. Whisnant (1987)]
-
Z' studies at the LHC: an update [M. Dittmar, A.S. Nicollerat, A. Djouadi (2003)]
-
Distinguishing Between Models with Extra Gauge Bosons at the ILC [S. Godfrey, P. Kalyniak, A. Tomkins (2005)]
: Using e-, e+ polarizations, Z' couplings can be measured precisely.
-
Determination of Z' Gauge Couplings to Quarks
and Leptons at Future Hadron Colliders [F. del
Aguila, M. Cvetic, P. Langacker (1993)]
-
Review of Z' Physics at Future Colliders [F. del
Aguila, M. Cvetic, P. Langacker (1993)]
-
Reconstruction of the Extended Gauge Structure from Z' Observables at Future Colliders [F. del
Aguila, M. Cvetic, P. Langacker (1995)]
-
Z' signal from the LEP2 data [A.V. Gulov, V.V. Skalozub (2006)]
-
Probing a Very Narrow Z' Boson with CDF and D0 Data [D. Feldman, Z. Liu, P. Nath (2006)]
-
Higgs and Z' Phenomenology in B-L extension of the Standard Model at LHC [W. Emam, S. Khalil (2007)]
-
Like-sign dilepton signals from a leptophobic Z' boson [F. del Aguila, J.A. Aguilar-Saavedra (2007)]
- The mixing angle of Z-Z'
- Forward-Backward Asymmetry to distinguish the models
The Forward-Backward asymmetry of the vector boson contains the
information of the charge assignments. It is useful in identifying
gauge bosons.
A_FB versus E6 mixing angle for M_Z' = 0.2 TeV (dotted-dashed), 0.3
TeV (dotted) at p pbar and M_Z' = 0.5 TeV (solid) and 1
TeV (dashed) at p p hadron colliders; A_FB versus
rapidity for M_Z' = 1 TeV at p p collider
-
The Measurement of FB Asymmetry in Electron-Positron Pairs (slides) [G. Veramendi (2004)]
-
New heavy gauge bosons in p p and p anti-p collisions [P. Langacker, R.W. Robinett, J.L. Rosner (1984)]
-
Forward-Backward Asymmetries in Hadronically Produced Lepton Pairs [J.L. Rosner (1995)]
-
Production, decays, and forward-backward asymmetries of extra gauge bosons in E6 [V.D. Barger, N.G. Deshpande, J.L. Rosner, K. Whisnant (1987)]
-
The forward-backward asymmetry with Z' effects in the process e^{+} e^{-} --> mu^{+} mu^{-} [W.G. Ma, L.Z. Sun, Y.Y. Liu, Y. Jiang, C.H. Chang (1994)]
-
Les Houches "Physics at TeV Colliders 2003" BSM Working Group: Summary Report (See Part XX) [BSM WG (2004)]
- Distinguishing the Resonances
- Atomic Parity Violation
- Z' decay
- Electroweak Precision Test
- Leptophobic Z'
If Z' is leptophobic the dileptonic decay
modes would not make a resonance peak.
Also the large mixing between Z and Z' would be possible.
Since the current experimental lower limit on Z' mass is based
on the leptonic channels, less bound would be allowed
for the leptophobic Z' gauge boson.
-
Flavour-Changing Neutral Currents and Leptophobic Z' Gauge Bosons
Authors: Karine Leroux [K. Leroux, D. London (2001)]
-
Limits on a Light Leptophobic Gauge Boson [A. Aranda, C.D. Carone (1998)]
-
Constraints on leptophobic Z' models from electroweak experiments [Y. Umeda, G.C. Cho, K. Hagiwara (1998)]
-
Baryonic Z' connection of LEP R_{b,c} data with Tevatron (W,Z,\gamma)b\bar b events [V.D. Barger, K. Cheung, P. Langacker (1996)]
-
Gauge Kinetic Mixing and Leptophobic Z' in E_6 and SO(10) [T.G. Rizzo (1998)]
-
Leptophobic U(1)'s and the R_b - R_c Crisis [K.S. Babu, C. Kolda, J. March-Russell (1996)]
- FCNC (Flavor Changing Neutral Current) and CP violation
The family non-universal coupling of the Z' may be
possible, especially in a certain string-motivated
models.
In that case, the tree-level FCNC mediated by Z' is
possible.
The recent B-decay anomalies such as B --> phi K_S and B
--> pi K can be successfully explained with the enhanced electroweak
penguin sector provided by the flavor-changing Z'
without conflicts with B --> eta' K_S or Mercury EDM constraints.
Further, the flavor-changing Z' can be source of the 2.5
sigma deviation of A_b (See PDG EWPT review [J. Erler, P. Langacker (2003)])
[B --> pi K] and [B --> phi K_S] mediated by flavor-changing Z'
[B_S --> mu mu] mediated by flavor-changing Z'
-
String Consistency for Unified Model Building [S. Chaudhuri, S.W. Chung, G. Hockney, J. Lykken (1995)]
-
Flavor Changing Effects in Theories with a Heavy Z' Boson with Family Non-Universal Couplings [P. Langacker, M. Plumacher (2000)]
-
CP Violation
in Supersymmetric U(1)' Models [D.A. Demir,
L.L. Everett (2004)]
-
Explicit CP violation in a MSSM with an extra U(1)' [S.W. Ham, E.J. Yoo, S.K. OH (2007)]
-
Z' Mediated Flavor Changing Neutral Currents in B Meson Decays [V. Barger, C.W. Chiang, P. Langacker, H.S. Lee (2004)]
-
Solution to the B --> pi K Puzzle in a Flavor-Changing Z' Model [V. Barger, C.W. Chiang, P. Langacker, H.S. Lee (2004)]
-
Exclusive B-> M \nu \bar{\nu} (M= \pi, K, \rho, K^*) Decays and Leptophobic Z' Model [J.H. Jeon, C.S. Kim, J. Lee, C. Yu (2006)]
-
Nonuniversal Z' couplings in B decays [C.H. Chen, H. Hatanaka (2006)]
-
Semileptonic Lambda(b)-->Lambda neutrino antineutrino decay in the Leptophobic Z-prime model [B.B. Sirvanli (2007)]
-
K+ -> pi+ nu nu(bar) and FCNC from non-universal Z' bosons [X.G. He, G. Valencia (2004)]
-
D-bar D mixing constraints on FCNC with a non-universal Z' [X.G. He, G. Valencia (2007)]
Leptophobic models can have a sizable
flavor-changing in the quark sector even if the recent
measurement of B --> K(*) l+ l- constrains flavor-chaning
Z' significantly.
-
Electroweak Penguin and Leptophobic Z' model [S. Baek, J.H. Jeon, C.S. Kim, C. Yu (2006)]
-
New physics upper bound on the branching ratio of B_s --> l+ l- [A.K. Alok, S.U. Sankar (2005)]
-
Family nonuniversal Z-prime and b to s Gamma decay [R. Sever, A. Aydemir (2003)]
-
Constraints on heavy Z' couplings from \Delta S = 2 B^- -> K^- K^- \pi^+ decay [S. Fajfer, P. Singer (2001)]
- Z' coupling to limited particles
- Flavor-changing Z' in top quark physics
- Flavor-changing SM Z
- Dirac/Majorana Neutrino
- Primordial Nucleosynthesis
The Big Bang Nucleosynthesis (BBN) can provide the most
stringent limits on the Z' mass (multi-TeV range) when
the right-handed neutrinos are charged by TeV-scale U(1)'.
For the E6 angle where right-handed neutrinos almost
decouple from the Z', small Z' masses are also allowed.
-
Primordial Nucleosynthesis Constraints on Z' Properties [V. Barger, P. Langacker, H.S. Lee (2003)]
BBN Constraint on Z' mass with the mixing angle of 2
U(1)'s in E6
-
Primordial nucleosynthesis corners the Z' [J.L. Lopez, D.V. Nanopolous (1990)]
- Supernova
- Neutralino Spectrum
- Singlino-dominated Neutralino
- Neutralino Relic Density
Neutralino relic density in a U(1)' model and the MSSM
- Direct detection of the neutralino dark matter in a U(1)' model
- More dark matter in U(1)' models
A SM singlet fermion can be a dark matter under a U(1)'.
-
U(1)' dark matter [D.E. Brahm, L.J. Hall (1990)]
- Muon g-2
Muon g-2 provides the most stringent constraints to many new physics
models. If the deviation of 2.4 ~ 2.7 sigma between the SM and the BNL
E821 experiments is real, a viable TeV-scale model should be able to
explain it. The supersymmetric Z' model (both one singlet and multiple
singlets model) can explain it. -
Muon Anomalous Magnetic Moment in a
Supersymmetric U(1)' Model [V. Barger, C. Kao, P. Langacker, H.S. Lee (2004)]
The supersymmetric contributions to muon (g-2) involves
the loops of charginos and neutralinos.
The 2.4 sigma muon g-2 deviation solution (orange)
along with the CDM relic density solution (black square). The multiple
singlets model is used with small tan beta value of 2.5.
- Sneutrino dark matter
A right-handed sneutrino coupled to Z' can serve as a viable dark matter candidate satisfying all experimental constraints.
 -
Revival of the Thermal Sneutrino Dark Matter [H.S. Lee, K.T. Matchev, S. Nasri (2007)]
 
Relic density and direct detection constraints on sneutrino dark matter
- Electroweak Baryogenesis (EWBG)
- B, L asymmetry
- Higgs spectrum
Because of the mixing of the singlet and doublet Higgses, the LEP2 constraint of m_h > 104 GeV does not apply directly.
A much smaller mass of the Higgs is allowed while not violating the LEP2 results.
Higgs sector is one of the most sensitively altered
sectors with a U(1)' symmetry and its breaking singlet
Higgs.
-
Higgs Sector in Extensions of the MSSM [V. Barger, P. Langacker, H.S. Lee, G. Shaughnessy (2006)]
The lightest Higgs mass spectrum in various MSSM extensions [top:
doublet only (MSSM-like), bottom: mostly singlet]. The points under the
LEP curve are allowed (Mh < 114 GeV is possible). The UMSSM is a
U(1)'-extended MSSM.
-
Higgs at collider
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